HomeMy WebLinkAbout20101466.tiff Apra
•
PRELIMINARY
DRAINAGE STUDY
FOR
DRY CREEK REGIONAL URBANIZATION AREA
WELD COUNTY, COLORADO
•
PREPARED FOR:
TODD CREEK VILLAGE METROPOLITAN DISTRICT
10450 EAST 159TH COURT
BRIGHTON, CO 80602
(303) 799-6000
PREPARED BY:
h Manhard.
CONSULTING
7442 SOUTH TUCSON WAY
SUITE 190-A
CENTENNIAL, CO 80112
PHONE: (303) 708-0500 FAX: (303)708-0400
• July 2009
MANHARD CONSULTING LTD. PROJECT-EGWCC-6069
2010-1466
•
Engineer Certification of Drainage Study
I hereby certify that this report for the preliminary drainage study of Dry Creek RUA was
prepared by me (or under my direct supervision) in accordance with the provisions of the
Weld County Storm drainage criteria for the
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Registered Professional Engineer % : 039719D r
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Weld County—Dry Creek R.U.A.
P:1EgwccldocumentslstormWater Reporla\Drainage Study l2_Engineer Cert.doc
Table of Contents• 1. Introduction
1.1. Purpose
1.2. Scope
2. Design Criteria
2.1. Drainage Basins
2.1.1. Big Dry Creek
2.1.2. Irrigation Ditches
2.2. FEMA Flood Insurance Rate Maps and Studies
2.2.1. Identify Restrictions and Concerns
2.2.2. Flood Hazard Mitigation
• Regional Detention
• Irrigation Inundation Management
2.3. Fluvial Geomorphology
2.4. Jurisdictional Agencies
• Weld County
• Ditch Companies
• CDPHE
• CDWR
• FEMA
• USACE
• • NRCS
3. Drainage Design
3.1. Hydrologic Analysis
3.1.1. Rainfall Intensity
3.1.2. Soils
3.1.3. Release Rate
3.1.4. Detention Storage
3.2. Hydraulic Analysis
3.3. Water Quality
• Detention/Retention Basins
• Bio-retention Areas
• Sand Filters
• Infiltration Trenches and Enhanced Swales
• Proprietary Stormwater Treatment Devices
4. Conclusion
Bibliography
•
Weld County-Dry Creek R.U.A.
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• Appendices
Tab 2. Exhibits
1. Aerial Exhibit
2. Existing RUA Topography Exhibit
3. Overall Drainage Exhibit
4. Key Impact Locations Exhibit
Tab 3. Soils Reports& Exhibits
Tab 4. National Flood Insurance Program (NFIP)
1. NFIP Programs
2. FEMA Flood Insurance Rate Maps
Tab 5. Jurisdictional Permits
1. Weld County— Drainage Impact& FHDP
2. CDPHE—General Permit Application and SWMP Preparation Guidance
3. CDWR—Dam Safety Permit
4. FEMA MT-1 & MT-2 Forms
Tab 6. Hydrology Data
1. Rainfall Data
2. Urban Drainage and Flood Control Excel Spreadsheet Link
•
•
Weld County—Dry Creek R.U.A.
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•
1.0 Introduction
This report presents conceptual calculations and preliminary stormwater analysis suitable for
future planning within the Dry Creek Regional Urbanization Area (RUA). The Dry Creek RUA
encompasses approximately 2,100 acres of rolling agricultural lands drained by the Big Dry
Creek. The Brantner Ditch provides irrigation water in the area and may have impacts to
drainage during heavy precipitation events. The RUA incorporates portions of Sections 21, 26,
27, 28 & 35 of Township 1 North, Range 67 West of the sixth principal meridian, County of
Weld, State of Colorado. The RUA boundary limits are detailed in the Aerial exhibit located in
Tab 2.
1.1 Purpose
In anticipation of future land development within the southern Weld County regional planning
area, this report summarizes key water resources characteristics and considerations of the Dry
Creek RUA. The enclosed information will assist in identifying and prioritizing existing flood
hazard risks and potential developmental impacts to existing land uses, infrastructure and
properties within the Dry Creek RUA as well as providing recommendations for future
infrastructure, storm water management and ecologic improvements.
1.2 Scope
The scope of this study is to determine potential developmental impacts to existing stormwater
management facilities, services and properties within the Dry Creek RUA and to provide
preliminary stormwater recommendations including possible locations for regional detention and
• preliminary detention volume requirements for development. Hydrologic and hydraulic analyses
specific to generating Flood Hazard Area Determinations (FHAD) throughout the RUA is beyond
the scope of this report though is encouraged prior to future development within the vicinity of
major waterways.
2.0 Design Criteria
This section provides a summary of the existing surface drainage inventory, water resources
and floodplain mapping of the Dry Creek RUA. The stormwater characteristics analyzed during
this phase will be used to assist in the determination of potential developmental impacts to the
existing drainage system. Detailed analyses for specific properties within the RUA, suitable for
engineering estimates are beyond the scope of this study and will need to be conducted during
future development planning efforts.
2.1 Drainage Basins
The two major water features of the RUA are Big Dry Creek and Brantner Ditch. Generally, Big
Dry Creek flows in a northeasterly direction from Standley Lake to the South Platte River, while
the Brantner Ditch generally runs North-South paralleling the South Platte River. The major
surface drainage of the RUA comes from agricultural farmland, with small areas of light
industrial, farmsteads and fossil fuel infrastructure.
2.1.1 Big Dry Creek
The Big Dry Creek watershed consists of two primary tributaries, the Upper Tributary, water
draining to Standley Lake and the Lower Tributary, which is the main stem that drains from
Standley Lake to the South Platte River. Starting from the headwaters to Standley Lake, the
lower tributary may be defined as predominately rangeland. East-Northeast of Standley Lake,
• Big Dry Creek traverses throughout Westminster, in which this area is predominately urbanized
except for the open space riparian corridor, which was preserved in joint effort between
Jefferson County and the City of Westminster. Northeast of Westminster to the confluence of
Weld County—Dry Creek R.U.A.
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Big Dry Creek and South Platte River is predominately agricultural area, the RUA tributary to
Big Dry Creek is contained within this stretch of the drainage basin.
The main stem of Big Dry Creek drains diagonally through the RUA. Big Dry Creek hydrology is
significantly affected by Standley Lake and water rights from irrigation ditch company diversions.
During lower precipitation storm events most of the surface runoff infiltrates, drains to Big Dry
Creek or its tributaries or is blocked and possibly diverted to the local irrigation ditches. During
large storm events the irrigation ditches may receive surface runoff and possibly overflow to Big
Dry Creek. Irrigation ditches tend to run parallel with elevation and block or intercept overland
surface flows. This, along with a general lack of natural drainage ways, may make these
drainage ditches susceptible to flash flooding. Flash flooding will tend to inundate and then
overtop these irrigation ditches, especially during the spring when the irrigation ditches are
active. Overtopping flow will likely occur in an uncontrolled manner, potentially threatening
public safety and welfare. According to the Federal Emergency Management Agency (FEMA),
flash flooding ranks first as the cause of flood-related deaths in the U.S. Thus, measures to
accommodate ditch overtopping during flash floods and safely routing flows to Big Dry Creek
and other drainage ways capable of handling the capacity should be considered a high priority
during future development.
Since the creation of Standley Lake in the early 1900's, Big Dry Creek has been deprived of its
natural sediment load, which now aggregates into Standley Lake. Unlike many creeks in the
area, Big Dry Creek has not been confined or channelized by developmental activity and is still
• allowed to meander relatively naturally. The combination of sediment starvation along with high
stream velocities results in significant erosion problems, generally forming vertical soil cliffs on
the outside bank of a meandering stream (Chenowith and Associates, 1995). Future land
development designs should stabilize isolated erosion problems and incorporate fluvial
geomorphic concepts that are imperative to the long-term success of any future land uses in the
area.
2.1.2 Irrigation Ditches
The three ditches within the RUA are the Brantner, Brighton and Big Dry Creek Ditches. Due to
their location within the RUA the Brighton and Big Dry Creek Ditches will play a relatively minor
role in the development process within the RUA. Since nearly 3.5 miles of the Brantner Ditch
meanders throughout the Dry Creek RUA, it is certain to be a major design consideration during
the development process.
Brantner Ditch is the oldest irrigation system in Water District Number Two of the South Platte
River. Construction on the ditch first began by Brantner brothers as a means of irrigating crops
in the semi-arid eastern plains in 1860. The Ditch is officially eligible to be listed in the National
Register of historic features. The Brantner Ditch's daily average flow is 38.77 cfs and diverts
water on the average of 181 days during the irrigation year. The yearly average volume of
diverted water is nearly 14,000 ac-ft (Simmons, 1988). The Brantner and Brighton Ditches
irrigate 5,000 and 1700 acres respectively(HRC, 2007).
While the Brantner ditch plays a major role in successful agricultural activities in the area, it
provides little stormwater benefit from the minor attenuation of peak flows generated in large
storm events. In smaller more frequent storm events the ditch significantly influences the
• drainage patterns of the drainage basins by potentially blocking surface runoff, resulting in
absorption of the first quarter to half inch of rainfall and localized depressional storage or
surface flow diversion.
Weld County—Dry Creek R.U.A.
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2.2 FEMA Floodplain Maps and Studies
The Federal Emergency Management Agency (FEMA) delineated a floodplain for Big Dry Creek
more than 25 years ago, as an approximate 100-Year Flood Boundary (FEMA Zone A). This
delineation may be found on the FEMA Flood Insurance Rate Maps (FIRM), located in Tab 4.
Zone A's are flood hazard area delineations using approximate methods and do not have
assigned Base Flood Elevations (BFE's) for local municipality use. These Zone A's are
common in rural areas where development is unlikely and are not appropriate tools for detailed
engineering analysis and are only suitable for conceptual land planning and flood insurance
determination purposes. We recommend preparing updated floodplain modeling for Big Dry
Creek and its major tributaries and drainage basins over one square mile. Detailed studies for
planning and engineering purposes provide public safety benefits to the County and future
developments in addition to quantifying land areas more suitable for storm water management
and ecological enhancement or restoration.
Natural features should be ecologically enhanced by future development, by the protection and
enhancement of the channel banks, as well as the creation and enhancement of upland ponds
and wetlands. In developing the Dry Creek RUA the Brantner Ditch should be enhanced while
maintaining its original purpose of providing water for irrigation to the surrounding farmlands.
2.2.1 Identify Restrictions and Concerns
Since the scope of this study does not include a detailed hydrologic or hydraulic analysis,
• flooding hazards are based on general stormwater principles and should be refined with further
analysis. Major flood flow restriction locations within the RUA maybe found at the above grade
crossing of the Brantner Ditch and Big Dry Creek, and the Big Dry Creek crossings of County
Roads 6 and 19. Special design considerations should be taken within these areas for the
betterment of the entire region because of their ideal location for flood hazard mitigation.
2.2.2 Flood Hazard Mitigation
Organizing resources and assessing flood risks is only the first half of hazard mitigation
planning. The next step is to develop a mitigation plan and then implementing and monitoring
that plan. Planning regional detention basins and proper irrigation inundation management is
essential flood hazard mitigation of this region. To see a more detailed list of resources related
to flood hazard and associated risks, see the NFIP section of this report in Tab 4.
Regional Detention
To minimize future flash flooding along Big Dry Creek, multiple on-line regional detention basins
are recommended for flood control within this RUA. Ideal locations of such regional detention
basins are upstream of the above grade crossing of the Brantner Ditch and Big Dry Creek, the
Big Dry Creek crossings of County Roads 6 and 19, and the southeast corner of the Rule
Feedlot, north of the old railroad tracks. These regional detention locations have been detailed
on the Key Impact Locations Exhibit located in Tab 2. Providing regional detention in these
areas will not replace the need for detention throughout the entire RUA, but are the only
locations in which detention storage may be provided and serve a dual purpose of traditional
detention storage and upstream flood hazard mitigation.
Irrigation Inundation Management
• According to the Urban Drainage and Flood Control District manuals as amended by Weld
County, irrigation ditches must accept stormwater if they were constructed in such a way that
surface water would naturally be intercepted (WCSDC). Due to this practice, future
developments may release stormwater to local irrigation ditches under this criteria and local
Weld County—Dry Creek R.U.A.
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code. A common result in development is an increased volume of stormwater runoff due to the
increase in impervious area. Engineers commonly design retention ponds to reduce the peak
out flow from a site but in the addition to impervious area, total site runoff is usually increased
during development and may contribute to irrigation ditches remaining full for a longer period of
time. In some instances, local farmers have seen ditches nearly washed out during large storm
events; some believe this is due to the increased volume of water draining to the ditches after
upstream areas have been developed.
According to Colorado Drainage Law, irrigation companies may not escape liability if their
negligence contributed to or cooperated with an act of God to cause damage to real property.
Thus, designed overflows of irrigation ditches should be created in conjunction with
developments that subsequently block the ditches previous overflow route (WCSDC). Ideal
overflow locations are low-head crossings of irrigation ditches and creeks. Reasonable
measures should be taken to route such surface drainage overflow to its natural tributaries.
Several of the ditches were perched significantly above the natural land and present a potential
hazard in the event of embankment breach or failure to future land uses. We recommend that
overland flood routes consider the possibility of embankment failures and that flood routes be
designed to pass the bank full failure condition and also analyze ditch overtopping during the
base flood event. Ideal locations of such irrigation inundation management overland flood
routes have been detailed on the Key Impact Locations Exhibit located in Tab 2.
2.3 Fluvial Geomorphology
• Fluvial geomorphology is the study of geologic processes of streams and rivers. Scientific
research has significantly progressed our understanding of the processes of how rivers and
streams change over time. As part of their natural evolution, streams migrate and meander
dependent upon characteristics such as slope, sediment load, bed material and flow. Several
classification systems have been developed to help define the characteristics of streams and its
progress through some of the typical evolutionary stages, the most popular method being the
Rosgen method. Rosgen created nine classes of streams from Aa+ to G. The class defining
parameters include channel slope, entrenchment ratio, width to depth ratio and sinuosity
(stream meander). The primary factor of stream evaluation consists of determining the bank full
condition. The bank full condition occurs at the typical flow rate within the channel that defines
the stream geometry on a regular basis. Flows maybe higher or lower than bank full at any
given time, but the bank full flow condition governs most fluvial geomorphic processes.
Alterations to drainage patterns, which affect runoff volume, temperature and rate of flow,
include land use changes and increases or decreases to tributary area. These changes will
likely result in a new bank full flow, which can have significant impacts on existing streams,
including sediment deposition, erosion, changes in sinuosity, and bank stability problems. All
these factors should be evaluated and considered prior to significant modification to the
watershed.
Manmade solutions to limit or confine natural stream evolution often ignore or do not fully
incorporate the concept of a "living river". Incorporation of fluvial geomorphic concepts into
future land development is not only ecologically responsible, but imperative to the long-term
success of any future land uses in the area. Providing adequate room for natural river evolution
and meandering provides critical riparian and ecological habitat as well as floodplain storage for
high intensity rainfall events and flash floods. Often natural floodplains have been encroached
• on by agricultural activities, resulting in confined channels, ditches and streams. In addition to
loss of natural habitat, the flood carrying capacity of these areas becomes compromised. Due
to a reduction in available cross sectional area, the confined channel overflows into wide, flat
over bank areas potentially causing significant flooding, loss of crops and safety concerns.
Weld County—Dry Creek R.U.A.
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Roadways crossing streams often confine the stream in unnatural ways, limiting the streams
ability to naturally evolve by restricting upstream flow resulting in sediment deposition upstream
and erosion downstream. Bridge scour can be a major concern over time if bridge and pier
foundations become undermined. The power of water to washout culverts, bridges and
roadways is testament to the awesome force of nature and must be respected with sound
engineering and scientific principles for the safety of the general public.
As part of the development process, we recommend that stream restoration, bank stabilization
and floodplain management principles be incorporated into land planning activities. Adequate
corridors for stream evolution should be reserved as open space areas for the welfare of the
public. These corridors provide several benefits including ecological habitat, natural stream
evolution, floodplain management, water quality and recreation. We recommend limiting the
number of stream crossings and confining them to locations where fluvial geomorphic
processes are relatively stable. Though this may present challenges, this is a fundamental
concept of Low-Impact Development (LID). The decision for LID must be made during the early
planning stages since adoption of a LID project has major implications to the entire land
development process.
Finally, without an accurate stream assessment of Big Dry Creek the processes discussed
above are unknown in sufficient detail for sound engineering design. A stream classification
analysis should be performed to determine the bank full condition and the current evolutionary
state of the rivers. Additionally, pebble counts and bed analysis should be performed to better
• understand the sediment loading of these rivers and streams so that stable designs for bank
stabilization or stream restoration projects will be successful. This data will help determine the
necessary corridor for floodplain management and stream meandering as well as stable
channel locations conducive to bridge and roadway crossings.
Beyond the engineering concerns related to stream geomorphology, the placement of natural
stream structures such as pools and riffles provide important ecological parameters necessary
for proliferation of flora and fauna such as cool water temperatures, dissolved oxygen and fish
spawning habitat. The perennial streams in this arid area should be teaming with plant and
animal life, but existing conditions along the majority of these corridors has been denuded by
existing land uses, creating unnaturally unstable banks, erosion and sedimentation. Restoration
and beautification of these natural resources with consideration for future land development
needs can be integrated in an aesthetically pleasing and environmentally responsible manner
that still meets financial and economical goals.
2.4 Jurisdictional Agencies
Throughout the development process an assortment of permits and approvals will be required
prior to construction. This section of the report summarizes the most common permits and
approvals developers will likely encounter.
Weld County
Submitting to Weld County will be a requirement for all properties within the Big Dry Creek RUA,
since the entire RUA is within unincorporated Weld County. Upon submitting to the County,
they will forward a copy of the engineering submittal to any relevant municipality, which may
ultimately annex the development into their municipal limits. At that time, the municipality may
• comment on the development but until the property has been annexed into that community, the
County will issue all permits. Weld County permits include, but are not limited to, the Flood
Hazard Development Permit (FHDP) and Drainage Impact Fee. For a copy of these permits
visit the Weld County website (http://www.co.weld.co.us) or see Tab 5 of this report.
Weld County—Dry Creek R.U.A.
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Ditch Companies
Local ditch companies play an important role in the long-term future of the region. Thus, in the
case of a development impacting the amount of water draining to an irrigation ditch, the ditch
company being impacted must be contacted and it is recommended that all developments
obtain said ditch companies approval prior to construction. For detailed information regarding
local irrigation ditches you may contact the following:
Ditch Contact Phone Number
Brantner Ditch: Barry Marrs (303) 659-5596
Brighton Ditch: Bill Wright (303) 659-8276
Big Dry Creek Ditch: Gary Howard (303)659-0798
CDPHE
Prior to any development, a Stormwater Management Plan (SWMP) shall be developed and
continuously updated during the construction process. The Colorado Department of Public
Health and Environment-Water Quality Control Division (CDPHE), require this plan to minimize
erosion and sediment movement during the construction process. The SWMP is designed to
reduce erosion and sediment transport through stormwater runoff and wind losses. The
landowner is ultimately responsible for any erosion caused by land disturbing activities though
the developers contractor implements dust control measures. Erosion control blankets,
vegetation, mulching and other practices are often employed to limit sediment transport into the
local creeks and streams. These in conjunction with detention/retention ponds and Best
Management Practices (BMP's) make up a solid erosion control plan that shall be tracked and
• maintained during the SWMP process. Instructions for preparing a SWMP may be found under
Tab 5, within the Stormwater Discharge Associated with Construction Activity— General Permit
Application and SWMP Preparation Guidance.
CDWR
The Colorado Department of Water Resources (CDWR) established the Colorado Safety of
Dams Program to set forth reasonable dam engineering standards and a public record for
reviewing and performance of all dams. According to these regulations a Jurisdictional size
dam is a dam creating a reservoir with a capacity of more than 100 acre-feet, creates a
reservoir with a surface area in excess of 20 acres at the high-water line (HWL), or exceeds 10
feet in height measured vertically from the elevation of the lowest point of the natural surface of
the ground to the crest of the emergency spillway of the dam (CDWR, 2007). Jurisdictional
dams may be classified as Minor, Small or Large Dams. Naturally, as the size of the dam
increases, so do the permitting requirements. Figure 1 summarizes the classifications of
jurisdictional and non jurisdictional dams. A copy of the current application for the review of
plans and specifications for the construction or enlargement of a dam and reservoir has been
included in Tab 5.
•
Weld County—Dry Creek R.U.A.
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• FEMA
The Mitigation Directorate, a component of FEMA, manages the National Flood Insurance
Program (NFIP). The three components of the NFIP are: Flood Insurance, Floodplain
Management and Flood Hazard Mapping. As previously discussed, Big Dry Creek has
delineated floodplain; those limits are used to determine flood insurance requirements. During
the development of the RUA, floodplain management of Big Dry Creek will play an important
role in the process. In manipulating the floodplain, going through the FEMA MT-1 and/or MT-2
process will be required. MT-1 forms address minor fill placement within the floodplain or
inadvertent placement of structures within the floodplain. These are resolved using Letters of
Map Revision based on Fill (LOMR-F) or Letters of Map Amendment (LOMA). MT-2 forms
address significant alterations to the floodplain that require extensive hydraulic and/or
hydrologic modeling and are called Letters of Map Revision (LOMR) or Conditional Letters of
Map Revision (CLOMR). For more information regarding this process you may review the FEMA
MT-1 and MT-2 permits located in Tab 5.
USACE
The U.S. Army Corps of Engineers (USACE) regulates the disturbance of all army corps
wetlands nationwide. In making decisions on whether to grant, deny or set conditions on
permits, District Commanders are required to consider all factors in the public interest, including
economic development and environmental protection. Regional or nationwide general permits
cover numerous relatively minor activities in wetlands, thus all wetland permitting shall be
handled on a case-by-case basis and usually begin with a jurisdictional determination followed
by a permit dependent upon the proposed activity.
NRCS
• The National Resources Conservation Service (NRCS) has expressed concerns to local farmers
regarding flooding, sediment loads and stream stability. These concerns were addressed by
developing a proposal for grant funding for stream stabilization measures in rural Adams and
Weld County—Dry Creek R.U.A.
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Weld Counties from 152nd Avenue to the confluence of the South Platte River along Big Dry
Creek (Rogers, 1997). This proposal documents the history of the watershed and the resulting
erosion issues commonly associated with unmanaged stream geomorphology. The main
objectives of the NRCS are to generate conservation practices to reduce soil erosion and
improve water quality; subsequently this improves wildlife habitat and cropland/livestock health.
3.0 Drainage Design
Floodplain management is the process of setting forth corrective and preventative measures for
reducing flood damage. The design and enacting of such process commonly starts with the
development of a hydrologic and hydraulic analysis. This section of the report details common
practices of the region and sets forth general engineering practices that should be utilized
during the preliminary design of the RUA.
3.1 Hydrologic Analysis
Hydrologic analysis estimates the rate of runoff, runoff volume and time distribution of flow for
either a historical storm event or an industry standard storm, most commonly the 1% annual
storm event (100-yr storm). Many physical characteristics contribute to this estimate of flow
including, but not limited to: rainfall, soil type, impervious percentage and flood storage. These
physical characteristics often change depending on the time of year. Weld County and
subsequently the Dry Creek RUA is generally semi-arid with warm summers, mild winters and
an agricultural growing season of approximately 138 days. Weld County has a semi-arid
climate, which is commonly characterized by relatively low humidity, low rainfall, moderate to
• high winds and a large range in daily temperatures. The annual precipitation ranges from 11.6
inches at Greeley to 13.9 inches in the northeastern part of the county, with an average snowfall
of 27 inches per year (Colorado Agricultural Statistics, 2000). Annual evaporation is about five
times larger than annual precipitation (USGS, 1995). In flood flow conditions the flood storage
available within the drainage ditch diversions have minimal impact on the drainage basin and
are commonly ignored in regional hydrologic studies. The mountainous regions generate
particularly high flows in the spring due to a combination of snowmelt and seasonal rains.
These conditions contribute to a higher chance of flash flooding during that season, but in most
regional flood studies, peak flood events are generated from high intensity late summer storms.
3.1.1 Rainfall
The Urban Drainage and Flood Control District Storm Drainage Criteria Manual, in which Weld
County has adopted with minor alterations (WCSDC), provides accurate rainfall data based on
the Precipitation-Frequency atlas of the Westem United States, Volume III-Colorado (NOAA
Atlas) published by the National Oceanic and Atmospheric Administration (NOAA) in 1973. This
data is necessary for the Colorado Urban Hydrograph Procedure (CUHP) hydrological
modeling, which is commonly used in generating an estimate of flood flow in Colorado. Figures
RA-1 thru RA-12 of the WCSDC are rainfall isohyetal maps of the region, based on this data
Manhard interpolated the location of the RUA and compiled that data into Figure 2, as seen to
the right. Figures RA-1 thru RA-12 may be found under Tab 6 of this report.
Dry Creek RUA Rainfall
1 Hr 2 Hr 3 Hr 6 Hr
2-Yr 0.95 1.12 1.25 1.45
5-Yr 1.33 1.56 1.72 1.99
10-Yr 1.59 1.85 2.04 2.34
•
25-Yr 2.03 2.31 2.53 2.86
50-Yr 2.30 2.62 2.86 3.24
100-Yr 2.67 3.01 3.26 3.66
Figure 2
Weld County—Dry Creek R.U.A.
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3.1.2 Soils
The soils of the region are generally separated by Altvan Loam - B - 0.1%
watershed. The soils within the South Platte watershed Aquolls and Aquepts - B - 4.7%
are mostly Aquolls and Aquepts, which are poorly Haverson Loam - B - 6.3%
drained, slow permeable soils. The soils along the Big Kim Loam - B - 2.9%
Dry Creek are mainly Weld and Olney while the higher Nunn Loam - C - 22.7%
elevations within the RUA are largely Nunn soils, all of Olney Loam - B - 14.5%
which are deep, well drained, slow to moderate Otero Loam - B - 0.6%
permeable soils (NRCS, 2006). Renohill Clay Loam - C - 2.6/°
Tassel Sandy Loam - D - 0.3%
Figure 3 summarizes the soil types of the RUA by Soil Weld Loam - C - 26.5%
Name — Hydrologic Soil Group — Percentage of RUA. Wiley-Colby Complex - B - 17.8%
Water - - - 1.0°/p
The detailed soil report and basis of the summary table
can be found under Tab 3. Figure 3
Some of the RUA is currently considered as farmland of statewide and local importance (i.e.,
prime farmland). This includes the Kim loam (Soil Nos. 33 and 34), Olney fine sandy loam (Soil
No. 48), Otero sandy loam (Soil No. 52) and the Wiley-Colby complex (Soil No. 83). These soils
are roughly located on or around the high points of the RUA. Conversely, even more of the
RUA would be prime if the soils were drained, protected from flooding, or if not frequently
flooded by irrigation. These soils include the Aquolls and Aquepts (Soil No. 4) located mostly in
the South Platte River watershed. The remaining soils throughout the RUA would be
• considered prime farmland if irrigated.
Description of Major Soil Groups in the RUA:
Nunn loam/clay loam (Soil Nos. 39, 40, 41, and 42) is a deep, well-drained soil formed in mixed
alluvium. Small, long, and narrow pockets of sand and gravel may be present. This soil type
encompasses a very large portion of the southwest and northwest portion of the RUA.
AGRICULTURE POTENTIAL:Would be prime farmland if irrigated
HABITAT: In the RUA this soil is almost entirely used for irrigated crops, but is also suitable for
tree and shrub plantings. When this soil type is used for rangeland and its condition
deteriorates, this soil type is prone to weed invasion.
URBAN DEVELOPMENT POTENTIAL: This soil has a high shrink-swell potential, thus a higher
emphasis on drainage around building foundations and roadways must be made to ensure long-
term sustainability. Those areas that are not well drained will have a fair to low potential for
urban development(USDA, 1980).
Weld loam (Soil Nos. 78 and 79) is a deep, well-drained loamy soil formed in eolian deposits
located mostly in the central portion of RUA.
AGRICULTURE POTENTIAL: Would be prime farmland if irrigated
HABITAT: This soil type is good for all types of seeding and planting as long as weed controls
are implemented to ensure establishment and survival.
URBAN DEVELOPMENT POTENTIAL: This soil has a good potential for urban and recreational
development. The limiting factor is a shrink-swell potential of the subsoil as it wets and dries, if
this region is not well drained (USDA, 1980).
Aquolls and Aquepts soils (Soil No. 4) are deep, poorly drained soils associated with
• depressions, ditches, stream terraces, or center pivot irrigation areas that are frequently
flooded. In the RUA, this soil type is found near the pond in the northwest corner of the RUA,
immediately north of Big Dry Creek where Brantner Ditch crosses it, and immediately north of
the railroad bed where the land is being irrigated by a center pivot.
Weld County—Dry Creek R.U.A.
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Agricultural Potential:Would be prime if the soils are well-drained.
Habitat: This soil type is listed as hydric and can exhibit wetland characteristics because of high
clay content and prolonged anaerobic conditions caused by excessive inundation. These soils
often support wetland vegetation because the water table is at or near the surface during the
irrigation season (USDA, 1980).
Urban Development Potential: This soil type is prime for wetlands or detention ponds but if well
drained maybe conducive to urban development.
Wiley-Colby complex (Soil Nos. 82 and 83) is also a deep, well-drained soil formed in
calcareous eolian deposits (e.g., wind deposited soils containing measurable amounts of
calcium carbonate). This soil type is generally located along the center ridgeline of the RUA.
Agricultural Potential: Considered Prime Farmland
Habitat: This soil is suitable for all irrigated and non-irrigated crops, rangeland, and wildlife
habitat. Because of its position in the landscape, this soil has moderate erosion potential
(USDA, 1980).
Urban Development Potential: This soil is well-drained and prime for urban development.
Olney fine sandy loam (Soil Nos. 47 and 48) is a deep, well-drained soil located in mixed
outwash deposit areas along the southern Big Dry Creek floodplain.
Agricultural Potential: Considered Prime Farmland
Habitat: This soil is suitable for all types of crops and plantings. Native rangeland vegetation
best suited for this well drained sandy soil type is sand bluestem, sand reedgrass and blue
• grams.
Urban Development Potential: Due to this soils proximity to the Big Dry Creek and irrigation
ditches and its rapid permeability rate, this soil maybe best utilized as retention basins or
vegetated swales which will promote groundwater infiltration. Due to the soils rapid
permeability rate, fertilizers, sewage, and other pollutants can easily infiltrate and contaminate
groundwater (USDA, 1980), thus special consideration must be made in these areas to
minimize potential contaminates.
3.1.3 Release Rate
The maximum allowable unit release rates per acre of tributary area for on-site detention
facilities vary, depending on the results of the 5-year undeveloped runoff rates, as detailed in
section 4.5 of the WCSDC. This methodology is suitable for detention determination for smaller
tributaries and provides an easy methodology for land planners, engineers and review agencies.
However, with recommended regional detention, over simplification of the storm water
management needs can create potentially severe problems associated with extended detention
times, excessive volume requirements and potentially increased flood stages due to
coincidental timing peaks on the downstream tributaries. Therefore, detailed hydrologic and
hydraulic engineering analysis of regional facilities is strongly recommended and consideration
by Weld County is requested regarding policy versus real impact on the floodplain.
Conservative estimates of the 5-year undeveloped runoff rate were calculated for a theoretical
10-acre parcel assuming 2% impervious area, a 2% land slope, and a time of concentration of
approximately 14 minutes. The soils in the area are predominately hydrologic soil group B and
C. The Urban Flood Control District created a spreadsheet with various detention storage
calculation methodologies. The FAA modified rational method was used for this analysis. A
• weighted average of the computed runoff rate resulted in a 5-year flow of 3.8 cubic feet per
second (cfs) for the RUA. This equals 0.38 cfs/ac, which was used as the allowable release
rate for the preliminary calculations below. Detention requirements would be slightly higher in
the C soils areas and slightly lower in the B soils areas.
Weld County—Dry Creek R.U.A.
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•
3.1.4 Detention Storage
The recently updated Urban Flood Control District manual identifies three simplified procedures
for sizing on-site detention volumes according to the Weld County Storm Drainage Criteria
Manual: Empirical Equations, Rational Formula-based FAA Method and Full-Spectrum
Detention. The empirical equations are only applicable for small catchments not exceeding 90
acres and have not been included within this report. The Rational Formula-Based Modified FAA
procedure is only applicable for catchments up to 160 acres but it is recommended to limit the
use to catchments of 90 acres or less. Full-Spectrum method may be applied for catchments of
up to one-square mile, but is recommended to limit the use to catchments of 160 acres or less.
The Full-Spectrum method has not been historically used in Weld County and has not been
included in this report.
For catchments exceeding the maximum acreage as described above, CUHP generated
hydrographs is the recommended hydrologic procedure to obtain the required detention volume.
If the off-site tributary areas contribute runoff to an on-site detention facility, the fully developed
off-site land uses, must be included into the sizing of the on-site volumes in order to account for
the total runoff volume in the watershed (WCSDC).
Watershed Imperviousness, Single-Family Residential Two-Story Houses
9O •
• atl -- - 5.000 sq.ft.homes
I .
1-
14,000 sq.;t.homes]
r
r r
60 — / / / -
-
v r �� 3,000 sc. ft.homes
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r
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m 40 r-
cs r r , • I' "'+'
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7...:.............„...........-•••••"°---'-------'"--
�
I ea i •
s
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0 1 2 3 4 5 ',
Single Family Dwelling Units per Acre
• Figure 4
Weld County- Dry Creek R.U.A.
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Since the development process is a highly iterative process, in which potential land uses may
change several times prior to final engineering design Figure 5 compiles preliminary acreage
required to fulfill detention requirements based on the land use. The area required for the
detention assumes a detention pond depth of 4-feet with an additional 10% increase in area for
grading along the top of the basin. These differences are based on the impervious percentage,
as detail in Figure 5.
Rational Formula-Based Modified FAA Procedure
The Rational Formula-based on Federal Aviation Administration (FAA) detention sizing method
provides a reasonable estimate of on-site detention storage volume requirements. This method
provides sizing for one level of peak control and not multi-stage control facilities. The detention
sizing process is detailed on page SO-10 & 11 of the Urban Storm Drainage Criteria Manual,
revised 2008. However, please note that Weld County has amendments to this methodology as
specified in the WCSDC. A link to the UFCD Excel spreadsheet may be found under Tab 6.
Preliminar Engineering Detention Requirements Table
Impervious Percentage of Area
Land Use or Percentage Required Detention required for
Surface Characteristics (Ac-ft/acre) Proposed Detention
Business:
Commercial Areas 95 0.22 6.1%
• Neighborhood areas 85 0.19 5.2%
Residential:
Single-family
1 1 Lot per Acre 23 0.12 3.3%
1 2 Lots per Acre 32 0.12 3.3%
1 3 Lots per Acre 40 0.12 3.3%
1 4 Lots per Acre 47 0.13 3.6%
Multi-unit(detached) 60 0.14 3.9%
Multi-unit(attached) 75 0.16 4.4%
Apartments 80 0.17 4.7%
Industrial:
Light areas 80 0.17 4.7%
Heavy areas 90 0.20 5.5%
Parks, cemeteries 5 0.11 3.0%
Playgrounds 10 0.11 3.0%
Schools 50 0.13 3.6%
1 Preliminary approximation of impervious percentage obtained from the Figure 5 assuming an average
house size of 3,000 sq.ft.
Figure 5
3.2 Hydraulic Analysis
Hydraulic analysis uses the flows generated during the hydrologic process to determine base
flood elevations (BFE) and subsequently flood hazard area delineation (FHAD). This FHAD is
then used by FEMA to determine whether or not an existing or proposed building is reasonably
• safe from flooding. As previously discussed, an important step in the development of the RUA
is to determine accurate FHAD's for Big Dry Creek prior to development along its banks.
Weld County—Dry Creek R.U.A.
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During the design process general hydraulic concepts are strongly encouraged, such as: fluvial
geomorphology concepts, maintaining existing flood volumes and proper erosion control
measures. These concepts will significantly increase the likelihood of the long-term
sustainability of future development. Please refer to the WCSDC for detailed drainage criteria
for final engineering.
3.3 Water Quality
According to the U.S. Environmental Protection Agency (EPA), "Stormwater runoff is a major
non-point source of water pollution. In urbanizing areas, where land-disturbing activities are
numerous, stormwater washes soil and sediment into surface waters causing increased levels
of turbidity and eutrophication, threatening fish and wildlife, and blocking drainage" (EPA, 1976).
To minimize these effects to the wildlife habitat, this section is meant to be a guide to utilizing
Best Management Practices (BMP) and erosion control measures within development of the
RUA.
Detention/Retention Basins
Detention and retention basins serve similar goals in the process of water quality control. They
both allow for the process of settling out potential contaminates and promote nutrient uptake
through biological activity. It is common to see some sedimentation accumulation in the bottom
of these basins after a large storm, some of that sediment may re-suspend during subsequent
storm events if not properly maintained. Weld County strongly discourages retention basins.
• Bio-retention Areas
Bio-retention areas are similar to retention basins in their stormwater functionality but are
usually smaller in size with thicker vegetation, to utilize their water quality benefits instead of
water quality functions. Primary variables that influences contaminate removal are influent
concentrations, hydrology, soils, climate, maintenance, vegetative species and density. Given
periodic sediment removal and plant harvesting should be a design consideration prior to
construction.
Sand Filters
Infiltration trenches usually have minor stormwater benefits but have the benefit of ground water
replenishing. These trenches commonly fill up during frequent storm events and are designed
as water conveyance and storage, but have little to no positive release except for direct
infiltration. Depending on the amount of sediment transport, periodic sediment removal is
necessary to maintain storage and infiltration capacity.
Infiltration Trenches and Enhanced Swales
Some consider bio-swales a combination of bio-retention and infiltration trenches, considering
they operate similarly. Bio-swales are designed to convey local drainage to downstream ponds
or other BMP measures, while pre-treating along the travel path. Bio-swales are best used to
pre-treat surface drainage from large areas of pavement. According to many studies the
removal rates fall into the medium range of BMP's and are best used in conjunction with other
practices.
Proprietary Stormwater Treatment Devices
Proprietary water quality systems may be classified by these categories; hydrodynamic system
• (vortex separators), wet vaults, media filters and underground infiltration systems.
Hydrodynamic systems utilize gravity to generate a "vortex" that moves water in a circular
manner to promote separation and deposition of sediment. These devices are suitable to
remove course particles in small drainage areas. Wet vaults promote settling of particles
Weld County—Dry Creek R.U.A.
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through detention and use of internal weirs and baffles. These devices are commonly designed
for low flow conditions and have little effect during larger storm events. Commercially available
media filters range from fabrics, activated carbon, perlite, zeolite or combinations there of.
Media filters are usually the most effective in removing unwanted pollutants but are also the
most costly. Underground infiltration systems may be prefabricated pipes and vaults or porous
pavement. They are designed for stormwater quantity benefits rather than the stormwater
quality benefits but have the potential to perform at an acceptable treatment level when
designed appropriately.
Additional BMP measures can be found in the WCSDC, Green Industry Best Management
Practices for Conservation and Protection of Water Resources in Colorado (Wright, 2008), as
well as other publications.
4.0 Conclusion
The general concepts and recommendations set forth in this report were compiled to minimize
the potentially negative impacts commonly associated with development while preserving the
economic benefits of more intense land uses. In generating a regional plan for detention
storage and incorporating "Living River" concepts into the design process, we are confident the
Dry Creek RUA will become a model for responsible and efficient urban development in Weld
County. This report was written in accordance with the provisions of the Weld County Storm
Drainage Criteria Manual.
•
•
Weld County—Dry Creek R.U.A.
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BIBLIOGRAPHY
• Aquatics Associates, 1998. Interim Report Results of the Aquatic Monitoring Program in Big
Dry Creek 1997. February.
B. R. Wheeler, G. C. Steinhardt, C. A. Sargent. No Date. Protecting Prime Farmland in
Indiana. Purdue University Agronomy Guide AY-245. Cooperative Extension Service, West
Lafayette, IN.
Camp, Dresser& McKee, Inc, 2005. Flood Hazard Area Delineation—South Platte River—
Adams County, Colorado. Prepared for Adams County.
(CDOW) Colorado Division of Wildlife, 1996. Prehearing Statement of the Colorado Division of
Wildlife, Dr. John Woodling. October 28, 1996.
(CDWR) State of Colorado Department of Natural Resources— Division of Water Resources
Office of the State Engineer. Rules and Regulations for Dam Safety and Dam Construction,
January 1, 2007.
Chenowith and Associates, 1995. Big Dry Creek Corridor Preliminary Biological
Characterization (Vegetation, Wildlife and Soils). Prepared for the City of Westminster.
Colorado Agricultural Statistics, 2000, Issued Cooperatively by National Agricultural Statistics
Service, Donald M. Bay, Administrator& Colorado Department of Agriculture, Don Ament,
Commissioner. Published by: Colorado Agricultural Statistics Service.
• (EPA) U.S. Environmental Protection Agency, 1976. Nonpoint Source Control Guidance:
Construction Activities. Technical Guidance Memorandum No. TECH-27. Washington D.C.
December.
(FEMA) Federal Emergency Management Agency, 1995. Flood Insurance Study, Adams
County, Colorado and Incorporated Areas. Volume 1 of 3.
(FEMA) Federal Emergency Management Agency, 1999. Flood Insurance Study, Weld County,
Colorado and Incorporated Areas. Volume 1 of 3.
(HRC) Hydrosphere Resource Consultants, Inc., 2007. Irrigated Acreage Served by Ditches
Diverting from South Platte River Downstream of Denver. June 28.
(NRCS) U.S. Department of Agriculture, Natural Resources Conservation Service, 1997. Grant
Application for Big Dry Creek Stabilization Project. June 15.
(NRCS) U.S. Department of Agriculture, Natural Resources Conservation Service, 2006. Soil
Survey of Weld County, Colorado, Southern Part.
(NRCS) U.S. Department of Agriculture, Natural Resource Conservation Service, 2008. Web
Soil Survey of Weld County, Colorado. U.S. Department of Agriculture. Washington, D.C.
Accessed, November 20.
• Robson, S.G., 1996. Ground Water Atlas of the United States, Segment 2: Colorado, Nevada,
and New Mexico: U.S. Geological Survey Atlas.
Weld County—Dry Creek R.U.A.
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• Rogers, Carolyn, 1997. Wright Water Engineers, Inc. Personal Communication with Carolyn
Rogers, U.S. Department of Agriculture Natural Conservation Service.
Simmons, R.L, Whitacre, C. & Sherow, J.E., 1988. Historic American Engineering Record
Branter Ditch. National Park Service Rocky Mountain Regional Office Department of the
Interior. Denver, Colorado.
Urban Drianage and Flood Control District (UDFCD), 2008. Urban Storm Drainage Criteria
Manural, Volume 1.
(USDA) U.S. Department of Agriculture, Soil Conservation Service, 1980. Soil Survey of Weld
County, Colorado, Southern Part. U.S. Department of Agriculture. Washington, D.C.
(USDA) U.S. Department of Agriculture, 2002. 2002 Census of Agriculture, Volume 1,
Geographic Area Series, Part 51. Issued by National Agricultural Statistics Service, R.
Ronald Bosecker, Administrator, June 2004.
U.S. Department of the Interior, Geological Survey. Frederick, 7.5 minute Colorado Quadrangle
Topographic Map. U.S. Geological Survey, Denver, Colorado.
U.S. Department of the Interior, Geological Survey. Fort Lupton, 7.5 minute Colorado
Quadrangle Topographic Map. U.S. Geological Survey, Denver, Colorado.
(USGS) U.S. Geological Survey, 1995. Ground Water Atlas of the United States, HA 730-C.
• (WCSDC)Weld County Public Works Department, 2006. Weld County Storm Drainage Criteria
Addendum to the Urban Storm Drainage Criteria Manuals, Volumes 1, 2 and 3, Weld
County Code Article XI and Appendix 8L. October 2006.
Wright Water Engineers, 1998. Big Dry Creek Watershed Summary of Existing Conditions.
Prepared for The Big Dry Creek Partnership.
Wright Water Engineers, Inc., 2008. Green Industry Best Management Practices for the
Conservation and Protection of Water Resources in Colorado, Third Release, May.
•
Weld County—Dry Creek R.U.A.
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TAB 2 - EXHIBITS
1. AERIAL EXHIBIT
2. EXISTING RUA TOPOGRAPHY EXHIBIT
3. OVERALL DRAINAGE EXHIBIT
4. KEY IMPACT LOCATIONS EXHIBIT
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TAB 3 - SOILS REPORT AND EXHIBITS
USDA United States A product of the National Custom Soil Resource
�-- Department of Cooperative Soil Survey,
Agriculture a joint effort of the United Report for
III States Department ofO \ RCS Agriculture and other Weld County ,
State
Natural agencies including the C o l o ra do ,
Resources Agricultural Experiment
Conservation Stations, and local
Service participants Southern Part
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June 25, 2009
. 4
Contents
Preface 2
How Soil Surveys Are Made 5
Soil Map 7
Soil Map 8
Legend 9
Map Unit Legend 10
Map Unit Descriptions 11
Weld County,Colorado, Southern Part 13
1—Altvan loam, 0 to 1 percent slopes 13
4 Aquolls and Aquepts,flooded 14
22—Dacono day loam, 1 to 3 percent slopes 15
26—Haverson loam, 1 to 3 percent slopes 16
32—Kim loam, 1 to 3 percent slopes 17
33--Kim loam, 3 to 5 percent slopes 18
34—Kim loam,5 to 9 percent slopes 19
39—Nunn loam,0 to 1 percent slopes 20
40—Nunn loam, 1 to 3 percent slopes 21
• 41—Nunn clay loam,0 to 1 percent slopes 22
42—Nunn clay loam, 1 to 3 percent slopes 23
46—Olney fine sandy loam,0 to 1 percent slopes 24
47—Olney fine sandy loam, 1 to 3 percent slopes 25
48--Olney fine sandy loam,3 to 5 percent slopes 26
52-I-Otero sandy loam,3 to 5 percent slopes 27
56—Renohill day loam, 0 to 3 percent slopes 28
57—Renohill day loam, 3 to 9 percent slopes 29
61—Tassel fine sandy loam, 5 to 20 percent slopes 30
78—Weld loam,0 to 1 percent slopes 31
79—Weld loam, 1 to 3 percent slopes 32
82—Wiley-Colby complex, 1 to 3 percent slopes 33
83—Wiley-Colby complex, 3 to 5 percent slopes 35
85—Water 36
References 37
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Custom Soil Resource Report
0 Map Unit Legend w._ _
y�,� .4 ,: wild;Counntyy.C.1o!eue.Seidel rail tCO``/;1y81 r'
vapUntlittynttlsl ?y Map UnIt Nanni„', AM9 ha at,:
1 Alban loam,0 to 1 percent slopes 0.3 0.0%
4 Aquons and Aquepts,flooded 103.7 4.7%
22 Dacap day loam,1 to 3 percent 0.2 0.0%
slopes
26 Hasson loam,1 to 3 percent slopes 137.5 6.3%
32 Kim loam,1 to 3 percent slopes 172 0.8%
33 Km loam,3 to 5 percent slopes 3.2 0.1%
34 Kin loam,5 to 9 percent slopes 43.7 2.0%
39 Nunn loam,0 to 1 percent slopes 23.7 1.1%
40 Nunn loam,1 to 3 percent slopes 198.9 9.1%
41 Nun day loam,0 to 1 percent slopes 28.9 1.3%
42 Mn'clay loam,1 to 3 percent slopes 243.7 11.2%
48 OMey Ins sandy loam,0 to 1 percent 38.8 1.7%
elopes
47 Olney ins sandy loam,1 to 3 percent 163.4 7.5%
slopes
• 48 Olney fine sandy loam,3 to 5 percent 116.6 5.3%
slope
52 Otero sandy loam,3 to 5 percent 12.5 0.6%
slopa
56 Re nol'i day loam,0 to 3 percent 25.3 1.2%
slopes
57 Denali day loan,3 to 9 percent 31.5 1.4%
slopes
61 Tassel fine sandy loam,5 to 20 7.6 0.3%
percent slopes
78 Weld loam,0 to 1 percent slopes 29.4 1.3%
79 Weld loam,1 to 3 percent slopes 549.7 25.2%
82 W9ey-Colby complex,1 to 3 percent 298.3 13.7%
slopes
83 vMsy-Copy complex,3 to 5 percent 90.5 4.1%
slopes
85 Water 21.2 1.0%
retake fer Area of Interest 2.183.9 100.0%
• 10
Custom Soil Resource Report
• Weld County, Colorado, Southern Part
1—Altvan loam, 0 to 1 percent slopes
Map Unit Setting
Elevation:4,500 to 4,900 feet
Mean annual precipitation: 14 to 16 inches
Mean annual air temperature:46 to 48 degrees F
Frost-fee period: 130 to 150 days
Map Unit Composition
Altvan and similar soils:90 percent
Minor components: 10 percent
Description of Altvan
Ong
Landform:Terraces
Down-slope shape: Linear
Across-slope shape:Linear
Parent material:Old alluvium
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.20 to 2.00 in/hr)
• Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:5 percent
Available water capacity:Low(about 5.7 inches)
Interpretive groups
Land capability classification(irrigated):3s
Land capability(noninigated):4e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to W inches:Loam
10 to 25 inches:Clay loam
25 to 60 inches:Gravelly sand
Minor Components
Cascajo
Percent of map unit:9 percent
Aquic haplustolis
Percent of map unit: 1 percent
Landfonn:Swabs
• 13
Custom Soil Resource Report
•
4—Aquolls and Aquepts, flooded
Map Unit Setting
Elevation:3,600 to 4,700 feet
Mean annual precipitation:12 to 16 inches
Mean annual air temperature:50 to 55 degrees F
Frost-free period: 100 to 165 days
Map Unit Composition
Aquolls and similar soils:55 percent
Aquepts, flooded, and similar soils:25 percent
Minor components:20 percent
Description of Aquolls
Setting
Landfonn:Drainageways, plains,depressions
Down-slope shape:Unear
Across-slope shape:Linear
Parent material:Recent alluvium
Properties and qualities
• Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Poorly drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to high
(0.06 to 6.00 in/hr)
Depth to water table:About 6 to 36 inches
Frequency of flooding:Frequent
Frequency of ponding:None
Calcium carbonate, maximum content: 10 percent
Maximum salinity:Slightly saline to moderately saline(8.0 to 16.0 mmhos/cm)
Sodium adsorption ratio, maximum:5.0
Available water capacity:Low(about 4.7 inches)
Interpretive groups
Land capability classification(irrigated):6w
Land capability(noninigated):6w
Ecological site:Salt Meadow(R067BY035CO)
Typical profile
0 to 8 inches:Variable
8 to 60 inches:Stratified sandy loam to clay
Description of Aquepts,Flooded
Setting
Landfonn:Stream terraces
Down-slope shape:Unear
Across-slope shape:Linear
• 14
Custom Soil Resource Report
• Parent material:Recent alluvium
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Poorly drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to high
(0.06 to 6.00 in/hr)
Depth to water table:About 6 to 36 inches
Frequency of flooding:Frequent
Frequency of ponding:None
Calcium carbonate, maximum content 10 percent
Maximum salinity:Slightly saline to moderately saline(8.0 to 16.0 mmhos/cm)
Sodium adsorption ratio, maximum:5.0
Available water capacity:Low(about 4.7 inches)
Interpretive groups
Land capability classification(irrigated):6w
Land capability(noninigated):6w
Ecological site:Wet Meadow(R067BY038CO)
Typical profile
0 to 8 inches:Variable
8 to 60 inches:Stratified sandy loam to Gay
Minor Components
Thedalund
Percent of map unit:10 percent
• Haverson
Percent of map unit 10 percent
22—Dacono clay loam, 1 to 3 percent slopes
Map Unit Setting
Elevation:4,550 to 4,970 feet
Mean annual precipitation: 14 to 18 inches
Mean annual air temperature:48 to 52 degrees F
Frost-free period: 140 to 160 days
Map Unit Composition
Dacono and similar soils:85 percent
Minor components: 15 percent
Description of Dacono
Setting
Lanoborm:Terraces
Down-slope shape:Linear
Across-slope shape:Linear
• 15
Custom Soil Resource Report
• Parent material:Mixed alluvium
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high(0.20 to
0.60 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:Moderate(about 6.3 inches)
Interpretive groups
Land capability classification(irrigated):2e
Land capability(noninigated):3s
Ecological site:Clayey Plains(R0676Y042CO)
Typical profile
0 to 12 inches:Clay loam
12 to 21 inches:Clay loam
21 to 27 inches:Clay loam
27 to 60 inches:Very gravelly sand
Minor Components
Altvan
Percent of map unit 9 percent
•
Nunn
Percent of map unit:6 percent
26 Haverson loam, 1 to 3 percent slopes
Map Unit Setting
Elevation:4,500 to 4,800 feet
Mean annual precipitation: 12 to 17 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 125 to 180 days
Map Unit Composition
Haverson and similar soils:85 percent
Minor components: 15 percent
Description of Haverson
Setting
Lardform:Flood plains, stream terraces
Down-slope shape:Unear
Across-slope shape:Unear
• 16
Custom Soil Resource Report
• Parent material:Stratified,calcareous alluvium
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content 15 percent
Gypsum, maximum content: 1 percent
Maximum salinity:Nonsaline to slightly saline(0.0 to 8.0 mmhos/cm)
Available water capacity:High(about 9.6 inches)
Interpretive groups
Land capability classification(irrigated):3e
Land capability(noninigated):4c
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 4 inches:Loam
4 to 6O inches:Stratified loamy sand to loam to clay loam
Minor Components
Vona
Percent of map unit:5 percent
• Hsidt
Percent of map unit 5 percent
Nunn
Percent of map unit 5 percent
32—Kim loam, 1 to 3 percent slopes
Map Unit Setting
Elevation:4,900 to 5,250 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature:46 to 52 degrees F
Frost-free period: 125 to 150 days
Map Unit Composition
Kim and similar soils:90 percent
Minor components: 10 percent
Description of Kim
Setting
Landform:Alluvial fans, plains
• 17
Custom Soil Resource Report
• Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed eolian deposits derived from sedimentary rock
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 5.95 inRtt)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Available water capacity:Moderate(about 9.0 inches)
interpretive groups
Land capability classification(irrigated):3e
Land capability(nonimgated):4e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 12 inches:Loam
12 to 40 inches:Loam
40 to 60 inches:Fine sandy loam
Minor Components
Otero
• Percent of map unit: 10 percent
33—Kim loam, 3 to 5 percent slopes
Map Unit Setting
Elevation:4,900 to 5,250 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature:46 to 52 degrees F
Frost-ftee period: 125 to 150 days
Map Unit Composition
Kim and similar soils:90 percent
Minor components: 10 percent
Description of Kim
Setting
Landform:Alluvial fans,plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed eofian deposits derived from sedimentary rock
• 18
Custom Soil Resource Report
• Properties and qualities
Slope:3 to 5 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 5.95 irVhr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Available water capacity:Moderate(about 9.0 inches)
interpretive groups
Land capability classification(irrigated):3e
Land capability(noninigated):4e
Ecological site:Loamy Plains(R087BY002CO)
Typical profile
0 to 12 inches:Loam
12 to 40 inches:Loam
40 to 60 inches:Fine sandy loam
Minor Components
Otero
Percent of map unit 10 percent
•
34 Kim loam, 5 to 9 percent slopes
Map Unit Setting
Elevation:4,900 to 5,250 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature:46 to 52 degrees F
Frost-free period 125 to 150 days
Map Unit Composition
Kim and similar soils:90 percent
Minor components: 10 percent
Description of Kim
Setting
Landform:Alluvial fans, plains
Down-slope shape:Unear
Across-slope shape: Unear
Parent material:Mixed eolian deposits derived from sedimentary rock
Properties and qualities
Slope:5 to 9 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
• 19
Custom Soil Resource Report
• Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 5.95 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Available water capacity:Moderate(about 8.8 inches)
Interpretive groups
Land capability classification(irrigated):4e
Land capability(noninigated):6e
Ecological site:Loamy Slopes(R067BY008CO)
Typical profile
0 to 10 inches:Loam
10 to 35 inches:Loam
35 to 60 inches:Fine sandy loam
Minor Components
Otero
Percent of map unit:6 percent
Valent
Percent of map unit:4 percent
• 39 Nunn loam, 0 to 1 percent slopes
Map Unit Setting
Elevation:4,550 to 5,000 feet
Mean annual precipitation: 12 to 18 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 115 to 180 days
Map Unit Composition
Nunn and similar soils:85 percent
Minor components: 15 percent
Description of Nunn
Setting
Landform:Terraces
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium
properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 in/hr)
• 20
Custom Soil Resource Report
• Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhosicm)
Available water capacity:Moderate(about 8.9 inches)
Interpretive groups
Land capability classification(irrigated):2e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 9 inches:Loam
9 to 29 inches:Clay loam
29 to 60 inches:Sandy loam
Minor Components
Itaverson
Percent of map unit: 10 percent
lteidt
Percent of map unit:5 percent
• 40 Nunn loam, 1 to 3 percent slopes
Map Unit Setting
Elevation:4,550 to 5,000 feet
Mean annual precipitation: 12 to 18 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 115 to 180 days
Map Unit Composition
Nunn and similar soils:85 percent
Minor components: 15 percent
Description of Nunn
Setting
Landform:Terraces
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
4111 21
Custom Soil Resource Report
• Frequency of ponding:None
Calcium carbonate,maximum content 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:Moderate(about 9.0 inches)
Interpretive groups
Land capability classification(irrigated):2e
Land capability(noninigated):4c
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 9 inches:Loam
9 to 29 inches:Clay loam
29 to 40 inches:Sandy loam
40 to 60 inches:Sandy loam
Minor Components
Dacono
Percent of map unit:5 percent
Heldt
Percent of map unit 4 percent
Altvan
Percent of map unit 3 percent
Plainer
Percent of map unit:3 percent
•
41—Nunn clay loam, 0 to 1 percent slopes
Map Unit Setting
Elevation:4,550 to 5,150 feet
Mean annual precipitation: 12 to 18 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 115 to 180 days
Map Unit Composition
Nunn and similar soils:85 percent
Minor components: 15 percent
Description of Nunn
Setting
Landform:Plains,terraces
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium and/or eolian deposits
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
• 22
Custom Soil Resource Report
• Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of pending:None
Calcium carbonate, maximum content: 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:High(about 9.1 inches)
interpretive groups
Land capability classification(irrigated):2e
Ecological site:Clayey Plains(R067BY042CO)
Typical profile
0 to 9 inches:Clay loam
9 to 29 inches:Clay loam
29 to 60 inches:Sandy loam
Minor Components
Heldt
Percent of map unit 7 percent
Dacono
Percent of map unit 4 percent
Altvan
Percent of map unit 4 percent
•
42—Nunn clay loam, 1 to 3 percent slopes
Map Unit Setting
Elevation:4,550 to 5,150 feet
Mean annual precipitation: 12 to 18 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 115 to 180 days
Map Unit Composition
Nunn and similar soils:85 percent
Minor components: 15 percent
Description of Nunn
Setting
Landform:Plains,terraces
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium and/or eolian deposits
Properties and qualities
Slope: 1 to 3 percent
• 23
Custom Soil Resource Report
• Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:High(about 9.1 inches)
Interpretive groups
Land capability classification(irrigated):2e
Land capability(nonirrigated):4e
Ecological site:Clayey Plains(R067BY042CO)
Typical profile
0 to 9 inches:Clay loam
9 to 29 inches:Clay loam
29 to 60 inches:Sandy loam
Minor Components
Ilaverson
Percent of map unit 9 percent
Heldt
Percent of map unit:6 percent
•
46 Olney fine sandy loam, 0 to 1 percent slopes
Map Unit Setting
Elevation:4,600 to 5,200 feet
Mean annual precipitation: 11 to 15 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 125 to 175 days
Map Unit Composition
Olney and similar soils:85 percent
Minor components:15 percent
Description of Olney
Setting
Landform:Plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed deposit outwash
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
• 24
Custom Soil Resource Report
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:Moderate(about 7.0 inches)
Interpretive groups
Land capability classification(irrigated):3e
Land capability(nonirrigated):4c
Ecological site:Sandy Plains(R067BY024CO)
Typical profile
0 to 10 inches:Fine sandy loam
10 to 20 inches:Sandy clay loam
20 to 25 inches:Sandy clay loam
25 to 60 inches:Fine sandy loam
Minor Components
Zigweld
Percent of map unit:8 percent
Vona
Percent of map unit:7 percent
•
47—Olney fine sandy loam, 1 to 3 percent slopes
Map Unit Setting
Elevation:4,600 to 5,200 feet
Mean annual precipitation: 11 to 15 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 125 to 175 days
Map Unit Composition
Olney and similar soils:85 percent
Minor components: 15 percent
Description of Olney
Ong
Landform: Plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed deposit outwash
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature:More than 80 inches
• 25
Custom Soil Resource Report
• Drainage class:Well drained
Capacity of the most limiting layer to transmit water(lCsat):Moderately high to high
(0.57 to 2.00 irdhr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of pending:None
Calcium carbonate, maximum content: 15 percent
•
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:Moderate(about 7.0 inches)
Interpretive groups
Land capability classification(irrigated):3e
Land capability(nonirrigated):4c
Ecological site:Sandy Plains(R087BY024CO)
Typical profile
0 to 10 inches:Fine sandy loam
10 to 20 inches:Sandy day loam
20 to 25 inches:Sandy day loam
25 to 60 inches:Fine sandy loam
Minor Components
Zigweid
Percent of map unit: 10 percent
Vona
Percent of map unit:5 percent
•
48 Olney fine sandy loam, 3 to 5 percent slopes
Map Unit Setting
Elevation:4,600 to 5,200 feet
Mean annual precipitation:11 to 15 inches
Mean annual air temperature:46 to 54 degrees F
Frost-free period: 125 to 175 days
Map Unit Composition
Olney and similar soils:85 percent
Minor components: 15 percent
Description of Olney
Setting
Landform:Plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed deposit outwash
Properties and qualities
Slope:3 to 5 percent
Depth to restrictive feature:More than 80 inches
• 26
Custom Soil Resource Report
• Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding: None
Calcium carbonate, maximum content: 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity Moderate(about 7.0 inches)
Interpretive groups
Land capability classification(irrigated):3e
Land capability(nonirrigated):4c
Ecological site:Sandy Plains(R067BY024CO)
Typical profile
0 to 10 inches:Fine sandy loam
10 to 20 inches:Sandy day loam
20 to 25 inches:Sandy day loam
25 to 60 inches:Fine sandy loam
Minor Components
Zigweid
Percent of map unit:9 percent
Vona
Percent of map unit 6 percent
•
52—Otero sandy loam, 3 to 5 percent slopes
Map Unit Setting
Elevation:4,700 to 5,250 feet
Mean annual precipitation: 12 to 15 inches
Mean annual air temperature:48 to 52 degrees F
Frost-free period: 130 to 180 days
Map Unit Composition
Otero and similar soils:85 percent
Minor components: 15 percent
Description of Otero
Setting
Landform:Plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Eohan deposits and/or mixed outwash
Properties and qualities
Slope:3 to 5 percent
Depth to restrictive feature:More than 80 inches
• 27
Custom Soil Resource Report
• Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 5.95 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 10 percent
Maximum salinity:Nonsaline to very slightly saline(0.0 to 4.0 mmhos/cm)
Available water capacity: Moderate(about 7.7 inches)
interpretive groups
Land capability classification(inigated):3e
Land capability(noninigated):4e
Ecological site:Sandy Plains(R067BY024CO)
Typical profile
0 to 12 inches:Sandy loam
12 to 60 inches:Fine sandy loam
Minor Components
Kim
Percent of map unit 12 percent
Vona
Percent of map unit:3 percent
•
56—Renohill clay loam, 0 to 3 percent slopes
Map Unit Setting
Elevation:4,850 to 5,200 feet
Mean annual precipitation: 11 to 16 inches
Mean annual air temperature:46 to 48 degrees F
Frost-free period: 100 to 160 days
Map Unit Composition
Renohill and similar soils:85 percent
Minor components: 15 percent
Description of Renohill
Setting
Landform:Plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Residuum weathered from shale
Properties and qualifies
Slope:0 to 3 percent
Depth to restrictive feature:20 to 40 inches to paralithic bedrock
Drainage class:Well drained
• 28
Custom Soil Resource Report
• Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate,maximum content:5 percent
Available water capacity:Low(about 5.6 inches)
Interpretive groups
Land capability classification(inigated):3e
Land capability(noninigated):4e
Ecological site:Clayey Plains(R067BY042CO)
Typical profile
0 to 9 inches:Clay loam
9 to 32 inches:Clay loam
32 to 36 inches:Unweathered bedrock
Minor Components
Ulm
Percent of map unit: 10 percent
Shingle
Percent of map unit:5 percent
• 57—Renohill clay loam, 3 to 9 percent slopes
Map Unit Setting
Elevation:4,850 to 5,200 feet
Mean annual precipitation: 11 to 16 inches
Mean annual air temperature:46 to 48 degrees F
Frost-free period: 100 to 160 days
Map Unit Composition
Penchi'and similar soils:85 percent
Minor components: 13 percent
Description of Renohill
Setting
Landform:Ridges, hills
Down-slope shape:Unear
Across-slope shape:Unear
Parent material:Residuum weathered from shale
Properties and qualities
Slope:3 to 9 percent
Depth to restrictive feature:20 to 40 inches to paralithic bedrock
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high (0.06 to 0.20 in/hr)
• 29
Custom Soil Resource Report
• Depth to water table: More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:5 percent
Available water capacity:Low(about 5.6 inches)
Interpretive groups
Land capability classification(irrigated):4e
Land capability(noninigated):4e
Ecological site:Clayey Plains(R067BY042CO)
Typical profile
0 to 9 inches:Clay loam
9 to 32 inches:Clay loam
32 to 36 inches:Unweathered bedrock
Minor Components
Shire
Percent of map unit:8 percent
Ulm
Percent of map unit:5 percent
• 61—Tassel fine sandy loam, 5 to 20 percent slopes
Map Unit Setting
Elevation:4,850 to 5,200 feet
Mean annual precipitation: 12 to 19 inches
Mean annual air temperature:46 to 52 degrees F
Frost-free period: 110 to 165 days
Map Unit Composition
Tassel and similar soils:85 percent
Minor components: 15 percent
Description of Tassel
Setting
Landfonn:Breaks
Down-slope shape:Unear
Across-slope shape:Linear
Parent material:Residuum weathered from sandstone
Properties and qualities
Slope:5 to 20 percent
Depth to restrictive feature: 10 to 20 inches to paralithic bedrock
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
• 30
Custom Soil Resource Report
• Frequency of pending:None
Calcium carbonate, maximum content 10 percent
Available water capacity:Very low(about 2.0 inches)
Interpretive groups
Land capability classification(irrigated):6e
Land capability(noninigated):6e
Ecological site:Sandstone Breaks(R067BY056CO)
Typical profile
0 to 11 inches:Fine sandy loam
11 to 15 inches:Very fine sandy loam
15 to 20 inches:Weathered bedrock
Minor Components
Otero
Percent of map unit:8 percent
Terry
Percent of map unit:7 percent
78—Weld loam, 0 to 1 percent slopes
• Map Unit Setting
Elevation:4,850 to 5,000 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature:46 to 55 degrees F
Frost-free period: 100 to 155 days
Map Unit Composition
Weld and similar soils:80 percent
Minor components:20 percent
Description of Weld
Setting
Landform:Plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Eolian deposits
Properties and qualities
Slops:0 to 1 percent
Depth to restrictive feature: More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 inlhr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of pending: None
Calcium carbonate, maximum content 6 percent
• • 31
Custom Soil Resource Report
• Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:High(about 10.2 inches)
Interpretive groups
Land capability classification(irrigated):2s
Land capability(noninigated):3e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 8 inches:Loam
8 to 15 inches:Clay
15 to 60 inches:Silt loam
60 to 64 inches:Silt loam
Minor Components
Keith
Percent of map unit:9 percent
Platner
Percent of map unit:6 percent
Wiley
Percent of map unit:5 percent
• 79—Weld loam, l to 3 percent slopes
Map Unit Setting
Elevation:4,850 to 5,000 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature:46 to 55 degrees F
Frost-free period: 100 to 155 days
Map Unit Composition
Weld and similar soils:80 percent
Minor components:20 percent
Description of Weld
Setting
Landform:Plains
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Eolian deposits
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately low to
moderately high(0.06 to 0.20 in/hr)
Depth to water table:More than 80 inches
• 32
Custom Soil Resource Report
• Frequency of flooding:None
Frequency of ponding: None
Calcium carbonate, maximum content:6 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:High(about 10.2 inches)
interpretive groups
Land capability classification(inigated):2e
Land capability(nonarigated):3e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 8 inches:Loam
8 to 15 inches:Clay
15 to 60 inches:Silt loam
60 to 64 inches:Silt loam
Minor Components
Keith
Percent of map unit 7 percent
Wiley
Percent of map unit 7 percent
Adana
Percent of map unit:6 percent
•
82—Wiley-Colby complex, 1 to 3 percent slopes
Map Unit Setting
Elevation:4,850 to 5,000 feet
Mean annual precipitation: 12 to 16 inches
Mean annual air temperature:48 to 54 degrees F
Frost-free period: 135 to 170 days
Map Unit Composition
Wiley and similar soils:60 percent
Colby and similar soils:30 percent
Minor components: 10 percent
Description of Wiley
Setting
Landfall':Plains
Down-slope shape:Linear
Across-slope shape: Linear
Parent material:Calcareous eolian deposits
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature:More than 80 inches
1111 33
Custom Soil Resource Report
• Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Maximum salinity:Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity:High(about 11.7 inches)
Interpretive groups
Land capability classification(irrigated):2e
Land capability(nonirrigated):4e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 11 inches:Silt loam
11 to 60 inches:Silty clay loam
60 to 64 inches:Silty Gay loam
Description of Colby
Setting
Landform:Plains
Down-slope shape:linear
Across-slope shape: Linear
Parent material:Calcareous eoiian deposits
Properties and qualities
• Slope: 1 3 perce
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 2.00 inthr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding: None
Calcium carbonate, maximum content: 15 percent
Available water capacity:High(about 10.6 inches)
Interpretive groups
Land capability classification(irrigated):3e
Land capability(nonirrigated):4e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 7 inches:Loam
7 to 60 inches:Silt loam
Minor Components
Heldt
Percent of map unit:4 percent
Weld
Percent of map unit:4 percent
Keith
Percent of map unit:2 percent
34
Custom Soil Resource Report
•
83—Wiley-Colby complex, 3 to 5 percent slopes
Map Unit Setting
Elevation:4,850 to 5,000 feet
Mean annual precipitation: 12 to 16 inches
Mean annual air temperature:48 to 54 degrees F
Frost-free period: 135 to 170 days
Map Unit Composition
W7iey and similar soils:55 percent
Colby and similar soils:30 percent
Minor components: 15 percent
Description of Wiley
Setting
Landform:Plains
Down-slope shape:Linear
Across-slope shape:Unear
Parent material:Calcareous eolian deposits
• Properties and qualities
Slope:3 to 5 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(ICsat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content: 15 percent
Maximum salinity: Nonsaline(0.0 to 2.0 mmhos/cm)
Available water capacity: High(about 11.7 inches)
interpretive groups
Land capability classification(irrigated):3e
Land capability(noninigated):4e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 11 inches:Silt loam
11 to Winches:Silty clay loam
60 to 64 inches:Silty clay loam
Description of Colby
Setting
Landfonn:Plains
Down-slope shape:Unear
• 35
Custom Soil Resource Report
• Across-slope shape: Linear
Parent material:Calcareous eolian deposits
Properties and qualities
Slope:3 to 5 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat):Moderately high to high
(0.57 to 2.00 inlhr)
Depth to water table: More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content 15 percent
Available water capacity:High(about 10.6 inches)
Interpretive groups
Land capability classification(irrigated):3e
Land capability(nonirrigated):4e
Ecological site:Loamy Plains(R067BY002CO)
Typical profile
0 to 7 inches:Loam
7 to 60 inches:Silt loam
Minor Components
Heldt
Percent of map unit 9 percent
Weld
• Percent of map unit 6 percent
85—Water
Map Unit Composition
Water. 95 percent
Minor components:5 percent
Minor Components
Aquolls
Percent of map unit:5 percent
Landform:Marshes
• 36
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Hydrologic Sod Group-Weld County,Colorado,Southern Part
• Hydrologic Soil Group
Hydrologic 3 1 Gnu'. summwiy.)sy w►unit WAN C ;Cewra&SOUuwrU►S$ 4
`Mapa6Rsymbol ,Mali unitnedla Ratln9 = I °AirebtAOl: .': .: Itiae MpfAO1, '`:
1 Altvan loam,0 to 1 percent B 0.2 0.0%
slopes
4 Aquolls and Aquepts,flooded D 103.9 4.7%
26 Hannon loam,1 to 3 percent B 138.0 6.3%
slapas
32 Ken loam,1 to 3 percent B 17.2 0.8%
slopes
33 Ken loam,3 to 5 percent B 4.2 02%
slopes
34 Ken loam,5 to 9 percent 8 44.6 2.0%
slopes
39 Nunn loam,0 to 1 percent C 26.1 1.2%
slopes
40 Nunn loam,1 to 3 percent C 201.7 9A%
slope&
41 Nunn day loam,O to 1 percent C 28.9 1.3%
slopes
42 Nunn clay loam,l to 3 percent C 249.9 11.3%
• slopes
46 Olney fro sandy loam,0 to 1 B 36.8 1.7%
percent slopes
47 Olney fine sandy loam,1 to 3 B 165.4 7.5%
percent slopes
48 Olney fine sandy loan.3 to 5 B 117.1 5.3%
percent slope
52 Otero sandy loam,3 to 5 B 14.2 0A%
oxen slopes
56 Renohid day loam,0 to 3 C 25.3 1.1%
percent slopes
57 Rennet day loam,3 to 9 C 31.5 1.4%
percent slopes
61 Tassel fine sandy loam,5 to D 7.6 0.3%
20 percent slopes
78 Weld loam,0 to 1 percent C 29.9 1.4%
slope
79 Weld loam.1 to 3 percent C 551.8 25.0%
slopes
82 Wiley-Copy complex,1 to 3 B 298.2 13.5%
percent slopes
83 Wdey-Copy complex,3 to 5 B 91.2 4.1%
percent slopes _
85 Water 21.2 1.0%
Totals for Area Interest _.. - 2.208.0 100.0%
liplaiSen Web Soil Survey 2.2 6/2512009
ConservResourcesationPage Stavin National Cooperative Soil Survey
Hydrologic Sod Group—Weld County,Colorado,Southern Part
• Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation,are thoroughly wet,and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups(A, B,C, and D)and
three dual classes(A/D, B/D,and CID).The groups are defined as follows:
Group A.Soils having a high infiltration rate(low runoff potential)when thoroughly
wet.These consist mainly of deep,well drained to excessively drained sands or
gravelly sands.These soils have a high rate of water transmission.
Group B.Soils having a moderate infiltration rate when thoroughly wet.These
consist chiefly of moderately deep or deep,moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture.These soils
have a moderate rate of water transmission.
Group C.Soils having a slow infiltration rate when thoroughly wet.These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture.These soils have a slow rate of water
transmission.
Group D.Soils having a very slow infiltration rate(high runoff potential)when
thoroughly wet These consist chiefly of clays that have a high shrink-swell
• potential,soils that have a high water table,soils that have a claypan or clay layer
at or near the surface,and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group(AID, BID,or CID),the first letter is
for drained areas and the second is for undrained areas.Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Lower
fpNatural Plenums Web Sod Survey 2.2 6125/2009
Conservation Service National Cooperative Soil Survey Page 4 of 4
•
TAB 4 - NATIONAL FLOOD INSURANCE PROGRAM (NFIP)
1. NFIP PROGRAMS
2. FEMA FLOOD INSURANCE RATE MAPS
•
•
D. NFIP PROGRAMS -
• Weld County currently participates in the National Flood Insurance Program (NFIP) and is
committed to help reduce flood losses by implementing floodplain ordinances that control
development within their floodplains.
CRS
The National Flood Insurance Program's (NFIP) Community Rating System (CRS) is a voluntary
program that encourages community floodplain management activities that exceed minimum
NFIP requirements. The three goals of the CRS are to:
• Reduce flood losses
• Facilitate accurate insurance rating
• Promote the awareness of flood insurance
As an incentive for program participation, flood insurance premium rates are discounted across
the community to reflect the reduced flood risk resulting from the community proactive
measures. CRS communities are placed in classes ranging from 1 to 10, with Class 1
communities receiving the maximum premium discount of 45 percent. Other classes receive
discounts in 5 percent increments.
The CRS classes for local communities are based on 18 creditable activities, organized under
four categories:
• Public Information
• Mapping and Regulations
• Flood Damage Reduction
• • Flood Preparedness
Weld County has a current CRS rating of 10, which equates to non-participation within the
program and no flood insurance premium reduction. The County's current CRS rating should
be evaluated periodically to take advantage of all of the current floodplain management
activities undertaken throughout the County. For example, community funded flood studies can
add as much as 1,346 points to a communities CRS score. Each class consists of a 500-point
credit range. The example above would place the CRS score at Class 8, which would provide a
10% reduction in flood insurance premiums.
FUNDING CONSIDERATIONS
FEMA provides several funding sources for public flood mitigation projects including property
acquisition, structure relocation/elevation, drainage improvement projects, or mitigation planning
activities. In order for a community to be eligible to apply for these funds however, the
community must be included in a FEMA approved Hazard Mitigation Plan. The Disaster
Mitigation Act of 2000 (DMA 2000) provides the legal basis for FEMA's mitigation plan
requirements for State, local and Indian Tribal governments as a condition of mitigation grant
assistance. DMA 2000 emphasizes the need for state, Tribal, and local entities to closely
coordinate mitigation planning and implementation efforts. DMA 2000 also established a new
requirement for local mitigation plans and authorized up to 7 percent of Hazard Mitigation Grant
Program (HMGP) funds available to a state to be used for development of state, Tribal, and
local mitigation plans.
• Weld County—Dry Creek R.U.A.
P:\Egwcddocumenls\StormWater Reports\Drainage Sludy\Tab 4-FEMA\1 NFIP.doc
Hazard Mitigation Planning is a process for communities to identify policies, activities and
• tools to implement mitigation actions. Mitigation is any sustained action taken to reduce or
eliminate long-term risk to life and property from a hazard event. This process has four steps:
• Organizing resources
• Assessing risks
• Developing a mitigation plan
• Implementing the plan and monitoring progress
HAZARD MITIGATION GRANT PROGRAM
The Hazard Mitigation Grant Program (HMGP) provides grant funding to States and local
governments in order to assist in the implementation of long-term hazard mitigation measures
after declaration of a major disaster. The purpose of the HMGP is to reduce the loss of life and
property due to natural disasters and to enable mitigation measures to be implemented during
the immediate recovery from a disaster. The HMGP is authorized under Section 404 of the
Robert T. Stafford Disaster Relief and Emergency Assistance Act.
PRE-DISASTER MITIGATION GRANT PROGRAM
The Pre-Disaster Mitigation (PDM) program provides funds to states, territories, Indian tribal
governments, communities, and universities for hazard mitigation planning and the
implementation of mitigation projects prior to a disaster event. Eligible PDM activities include
property acquisition, structure relocation/elevation, drainage improvement projects, or mitigation
planning activities. Funding these plans and projects reduces overall risks to the population and
structures, while also reducing reliance on funding from actual disaster declarations. PDM
grants are awarded on a competitive basis and without reference to state allocations, quotas, or
• other formula-based allocation of funds. PDM Grants require a local match of at least 25
percent.
FLOOD MITIGATION ASSISTANCE(FMA) PROGRAM
The FMA program was created as part of the National Flood Insurance Reform Act (NFIRA) of
1994 (42 U.S.C. 4101) with the goal of reducing or eliminating claims under the National Flood
Insurance Program (NFIP). FEMA provides FMA funds to assist States and communities
implement measures that reduce or eliminate the long-term risk of flood damage to buildings,
manufactured homes, and other structures insurable under the National Flood Insurance
Program. Property Mitigation activities are the only activities eligible for FMA Grants. All FMA
Grants require a local match of at least 25 percent.
REPETITIVE FLOOD CLAIMS PROGRAM
The Repetitive Flood Claims (RFC) grant program was authorized by the Bunning-Bereuter-
Blumenauer Flood Insurance Reform Act of 2004 (P.L. 108-264), which amended the National
Flood Insurance Act (NFIA) of 1968 (42 U.S.C. 4001, et al). Up to $10 million is available
annually for FEMA to provide RFC funds to assist States and communities reduce flood
damages to insured properties that have had one or more claims to the National Flood
Insurance Program (NFIP). Property Mitigation activities are the only activities eligible for RFC
Grants. RFC grants can provide up to 100 percent funding for eligible projects.
SEVERE REPETITIVE LOSS PROGRAM
The newest FEMA grant program is the Severe Repetitive Loss (SRL) grant program. The SRL
grant program was authorized by the Bunning-Bereuter-Blumenauer Flood Insurance Reform
• Act of 2004, which amended the National Flood Insurance Act of 1968 to provide funding to
Weld County—Dry Creek R.U.A.
P:\Egwcc\documents\StormWater Reports\Drainage StudylTab 4-FEMA\1_NFIP doc
reduce or eliminate the long-term risk of flood damage to severe repetitive loss structures
• insured under the NFIP. Limited information is currently available about this program, since
final guidelines have not been released, but FEMA has disclosed the structures eligible SRL will
be residential properties:
• That have at least four NFIP claim payments over$5,000 each, when at least two such
claims have occurred within any ten-year period, and the cumulative amount of such
claims payments exceeds $20,000; or
• For which at least two separate claims payments have been made with the cumulative
amount of the building portion of such claims exceeding the value of the property, when
two such claims have occurred within any ten-year period.
Eligible flood mitigation project activities include flood proofing (historical properties
only); relocation; elevation; acquisition; mitigation reconstruction (demolition rebuild); and minor
physical localized flood control projects. It is anticipated that the SRL grants will require a
standard local match of at least 25 percent, however in some cases up to 90 % of Federal funds
may be awarded for projects approved in States, and Territories with FEMA-approved Standard
or Enhanced Mitigation Plans.
•
• Weld County—Dry Creek R.U.A.
P:\Egwcc\documents\StormWater Reports\Drainage Study\Tab 4FEMA\t_NFIP.doc
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TAB 5 - JURISDICTIONAL PERMITS
1. WELD COUNTY- DRAINAGE IMPACT & FHDP
2. CDPHE - GENERAL PERMIT APPLICATION AND SWMP
PREPARATION GUIDE
3. CDWR- DAM SAFETY PERMIT
4. FEMA MT-1 & MT-2 FORMS
•
•
• 44Iw
Wilge
COLORADO
Instructions
1 Determine Impervious areas for
-Roof-use footprint of the house and garage, not the square footage of building
-Patio-use length and width
-Driveway-use length and width of gravel area or paved area
2 Enter into spreadsheet in appropriate sections
3 If you are a developer paving streets and installing sidewalks,curb and gutter,or other hard surfaces,
determine amount of impervious area of planned construction.
Include common areas such as kiosks, pool or clubhouses etc.
4 Enter into spreadsheet in appropriate sections
5 Drainage impact fee is 10 cents per square foot of impervious area
Multiply total square feet of impervious area by$0.10
Call B.Varrella or D. Bauer at Weld County Public Works with questions (970) 304-6496
•
•
• a' al
WIDc
COLORADO
Drainage Impact Fee Calculation Sheet
Roof Area
A Total Sq. Ft.
Sidewalk Area
Length Feet
Width Feet
B Total Sq. Ft. Multiply Length by Width
Patio Area
Length Feet
Width Feet
C Total Sq. Ft. Multiply Length by Width
Driveway Area 2
• Paved Length Feet
Paved Width Feet
D Paved Total Sq. Ft. Multiply Length by Width
Gravel Length Feet
Gravel Width Feet Multiply Length by Width
E Gravel Total Sq. Ft. Divide by 2 Sq. Ft.
Adjacent Street Area 3
Length Feet
Width Feet
F Total Sq. Ft. Multiply Length by Width
Impact FeePg per square foot of imperviousness
H Total Impervious Sq. Ft. AddA + B + C + D + E + F
+ B + C + D + E + F
iFFIA Total Fee Multiply H total by $0.10
Notes: 1 - Roof area includes all buildings requiring building permits
2 - Driveway area includes turn-around areas, parking areas
• 3-Adjacent Street area to be included for developers only
Revised 5-8-06
• FLOOD HAZARD DEVELOPMENT PERMIT (FHDP) SUBMITTAL CHECKLIST
APPLICATION REQUIREMENTS:
One (1) original application form plus three (3) copies.
One (1) original Supplemental Requirements (pages 3 &4) plus three (3) copies.
A Flood Hazard Development Permit map drawn and certified by a registered Professional
Engineer(P.E.), that meets specifications as listed on Pages 3 &4 of this guide.
One (1) legible copy of the deed or legal instrument identifying applicant's interest in the
property.
A Flood Hazard Development Permit (FHDP) Elevation Certificate (attached).
A Flood Hazard Development Permit elevation drawing of the proposed structure(s). Such
drawing shall delineate the Regulatory Flood Datum elevation in relation to the Lowest Floor
elevation of the structure as defined in the Weld County Zoning Ordinance, including
basements, crawlspaces, and other enclosed areas.
$180.00 application fee.
In an effort to increase efficiency and reduce Weld County staff time involved in re-binding
applications for mailing, all copies shall be collated into complete application packets and
bound with binder clips only. All maps are to be folded and included with each individual
packet. Applications bound in any fashion other than binder clip (spiral bindings, three ring
bindings, etc.) will require additional review time and may be returned to the applicant without
review.
Based upon the number of referral entities, Weld County staff may request additional copies of
the packets and maps.
An as-built certification, signed and sealed by a registered Professional Land Surveyor(P.L.S.),
shall be required by the Public Works Department prior to the release of a final grading permit,
building permit, or certificate of occupancy for any structure.
•
• FLOOD HAZARD DEVELOPMENT PERMIT (FHDP) PROCEDURAL GUIDE
APPLICATION FEE HEARINGS/MEETINGS PROCESSING TIME
$180.00 Public Works Department 45 days
Administrative Staff Review*
*As soon as practicable after a decision has been reached, the Public Works Department shall notify the
applicant of the action taken on the Flood Hazard Development Permit.
An additional investigation fee shall be added to the cost of the permit application when specific land
uses, buildings, manufactured homes, mobile homes, and structures that require a permit by the Weld
County Code are located, moved, operated, or constructed prior to obtaining a permit. The investigation
fee shall be 50% of the fee established by separate action by the Board of County Commissioners for
land-use applications. The payment of such investigation fee shall not relieve any persons from fully
complying with the requirements of the Weld County Code, nor from any other penalties.
PURPOSE
The purpose of this packet is to provide an applicant with information on the Flood Hazard Development
Permit (FHDP) application process. It is the responsibility of the applicant to be knowledgeable of the
specific requirements of the FHDP application process. Specific requirements regarding Flood Hazard
Development Permits may be found in Chapter 23 of the Weld County Code. A copy of the Weld County
Code is available online at www.co.weld.co.us (Quick Link- Policies and Ordinances)
•
INTENT
The purpose of the application is to give the applicant an opportunity to demonstrate through written and
graphic information how the proposed building sites, developments, and/or structures are reasonably
safe from flooding if they are to be located within the FW(Floodway), FP-1 District (100-year Floodplain)
and FP-2 District (500-year Floodplain), and that the proposal complies with the Weld County Code.
A completed application form and supporting materials will enable Weld County staff to process and
reach a decision within the time frame established for the Flood Hazard Development Permit process.
The Weld County Public Works Department shall be responsible for processing a Flood Hazard
Development Permit in the unincorporated areas of Weld County.
•
Updated 03-13-2008 2
SUPPLEMENTAL REQUIREMENTS
• The submission requirements are explained in Section 23-2-490 of the Weld County Code. The
following items shall be submitted with an application for a Flood Hazard Development Permit:
1. A completed application form (form attached).
2. Explanation of how the Floodplain Management Standards of Section 23-2-480 of the Weld
County Code, have been or will be met. These standards are listed on page 3 of this guide.
3. A Flood Hazard Development Permit map shall be submitted as part of the application
requirements. The map shall be drawn and certified by a registered Professional Engineer(P.E.)
licensed to practice in the State of Colorado, and shall meet the following specifications and show
the following information:
• Dimensions shall be a minimum of eight and one-half(81/2) inches wide by eleven (11) inches
high or another suitable size when approved by the Public Works Department.
• The name and address of the property owner.
• A legal description which describes the Section, Township and Range of the property under
consideration.
• Appropriate scale and a north arrow.
• Existing ground elevations, in the NGVD-29 or NAVD-88 vertical datum, at the development
•
site to 2.0-ft accuracy, with offsite elevations as needed.
• Water surface elevations of the Intermediate Regional Flood (100-year Base Flood Elevation,
or BFE) at the building site.
• The boundaries of the FP-1 District(100-year Floodplain), FP-2 District(500-year Floodplain)
or the FW District (Floodway) on the property. If the limits of the FW District(Floodway) are
not provided by the Federal Emergency Management Agency, a Floodway limit must be
determined through engineering calculations, and be documented by a registered
Professional Engineer (P.E.) licensed to practice in the State of Colorado.
• The location, shape, exterior dimensions, and distance from lot or property lines of each
existing or proposed structure.
• The proposed vehicular access to the property.
• Any fill, storage of materials, and drainage facilities located on the property.
4. Copy of the deed or legal instrument by which the applicant obtained an interest in the property.
5. Flood Hazard Development Permit Certification by a registered Professional Engineer(P.E.)
licensed to practice in the State of Colorado.
6. Any other relevant information which may be required by Weld County review staff.
•
Updated 03-13-2008 3
FLOODPLAIN MANAGEMENT STANDARDS
• The Public Works Department shall not approve a Flood Hazard Development Permit until it has been
determined that all applicable standards specified in Section 23-2-480 of the Weld County Code, have
been met by the applicant. The following floodplain management standards apply:
1. The applicant has met all applicable conditions listed in Section 23-5-250 or 23-5-260 of the
Weld County Code.
2. If a structure is to be elevated in order to meet the floodproofing requirements, the property owner
shall certify that the lowest floor is elevated (for existing structures which are being substantially
improved) or will be built(for new structures) to the level, or above, the regulatory flood datum.
The certificate shall include the elevation of the highest adjacent grade (HAG), the lowest
adjacent grade (LAG), and the existing (for substantially improved structures) or proposed (for
new structures) elevation of the lowest floor of the structure. The ground elevations and elevation
of the lowest floor of any existing structure shall be certified to be accurate by a licensed surveyor
or registered engineer. The regulatory flood datum is identified as being one foot(1.0 ft)
above the water surface elevation of an intermediate regional flood, also known as the
Base Flood Elevation (BFE).
3. A registered Professional Engineer (P.E.) shall certify that any non-residential structures which
are not elevated in order to be floodproofed are designed so the structure is watertight below the
elevation of the regulatory flood datum and that the structures are designed to be capable of
resisting the hydrostatic and hydrodynamic forces expected at the building site during an
intermediate regional flood. The Floodproofing Certificate from the Federal Emergency
Management Agency shall include the elevation in feet NGVD-29 or NAVD-88 above the BFE at
• the development site, and the proposed elevation of the lowest floor of any structures.
Alternatively, as a matter of public safety, Weld County staff may require flood venting for all new
construction and substantially improved structures to automatically equalize hydrostatic flood
forces on exterior walls.
4. A registered Professional Engineer(P.E.) shall certify that all new or replacement domestic water
wells or water supply, treatment, or storage systems are designed to prevent inundation or
infiltration of floodwater into such system by an intermediate regional flood (100-year flood).
5. A registered Professional Engineer(P.E.) shall certify that all new or replacement sanitary sewer
treatment systems, including individual sewage disposal systems, are designed to prevent
inundation or infiltration of floodwater into such system and to prevent discharges from such
systems into the floodwaters of an intermediate regional flood (100-year flood).
6. No encroachments, including fill, new construction, substantial improvements, and other
development shall be permitted unless certification by a registered Professional Engineer (P.E.)
or Architect is provided demonstrating that encroachments shall not result in any increase in flood
levels during the occurrence of an intermediate regional flood (100-year flood).
7. If the proposed use or structure is to be located in the FW(Floodway) District, a registered
Professional Engineer(P.E.) shall certify that the proposed use or structure, when built, will be
agricultural in use per Weld County Code 29-1-20, will not limit pr restrict the flow capacity of the
floodway, and will not cause any rise in the BFE per Weld County Code 23-2-480(1).
8. If fill material is to be used in the FP-1 (100-year Floodplain) or FP-2 (500-year Floodplain)
• Districts, a registered Professional Engineer (P.E.) shall certify that the fill material is designed to
withstand the erosional forces associated with an intermediate regional flood (100-year flood).
Updated 03-13-2008 4
ALTERATION OR RELOCATION OF A WATER COURSE
• Any use or development which causes or results in an alteration or relocation of a water course shall
comply with the requirements listed below. If the use or development does not include any new
construction or substantial improvement of structures and it only includes the alteration or relocation of a
watercourse, compliance with the following standards is the only requirement which must be met before
the Public Works Department may approve a Flood Hazard Development Permit. The applicant shall
provide evidence that:
1. Municipalities within a three mile radius of the proposed alteration or relocation have been notified
in writing of the proposed alteration or relocation.
2. The Colorado Water Conservation Board (CWCB) has been notified in writing of the proposed
alteration or relocation.
3. The Office of Insurance and Mitigation of the Federal Emergency Management Agency (FEMA)
has been notified in writing of the proposed alteration or relocation.
4. Any other Federal or State agency with jurisdiction over the proposed activities has been notified
and provides written approval of the proposed activities (i.e. US Army Corps of Engineers,
Colorado Department of Public Health and Environment, Colorado Department of Reclamation
Mining and Safety, etc.).
5. All responses from referral agencies identified in Items 1 through 4 above shall be copied to the
Weld County Department of Public Works for distribution to Weld County referral agencies.
• 6. A registered Professional Engineer(P.E.) shall certify that the flood carrying capacity within the
altered or relocated portion of the watercourse will remain the same after the alteration or
relocation as existed prior to the alteration or relocation. The certification shall also provide
evidence which substantiates that the alteration or relocation shall not adversely affect
landowners upstream or downstream from the alteration or relocation.
IMPORTANT NOTICE— POST CONSTRUCTION (AS-BUILT) REQUIREMENTS
When an applicant has obtained approval of a Flood Hazard Development Permit and has
been issued a building permit for new construction or substantial improvement to
existing structures in the Flood Hazard Overlay District, to verify compliance with the
approved FHDP application, an as-built Elevation Certificate and/or Floodproofing
Certificate must be certified by a registered Professional Land Surveyor (P.L.S.). This as-
built certificate must be completed and submitted to the Public Works Department prior
to approval of the final inspection of the building permit, and shall be forwarded to all
Weld County referral agencies.
•
Updated 03-13-2008 5
Ill FLOOD HAZARD DEVELOPMENT PERMIT (FHDP) APPLICATION
FOR PUBLIC WORKS DEPARTMENT USE DATE RECEIVED:
RECEIPT/AMOUNT# 1$ CASE#ASSIGNED:
APPLICATION RECEIVED BY PUBLIC WORKS REVIEWER:
Parcel Number: - - - -
(12 digit number-found on Tax I.D.information,obtainable at the Weld County Assess or's Office,or www.co.weld.co.us).
Waterway Name: Flood Insurance Rate Map(FIRM) Panel#: 080266-
Legal Description , Section_, Township_North, Range_West
FEE OWNER(S) OF THE PROPERTY:
Name:
Work Phone# Home Phone# Email Address
Street Address:
City/State/Zip Code
APPLICANT OR AUTHORIZED AGENT(See Below:Authorization must accompany all applications signed by Authorized Agent)
Name:
Work Phone# Home Phone# Email Address
Street Address:
City/State/Zip Code
1. General Description of Proposed Development: (Please check all that apply)
•
Residential Non-Residential Manufactured of Mobile Home
❑ New Construction El New Construction El On Single Lot
El Addition or Improvements El Addition or Improvements El In Mobile Home Park
El In Subdivision El Fill Material El Fill Material
El Fill Material El Watercourse Alteration El In Mobile Home Subdivision
Other
2. Brief Narrative Description of Proposed Development:
3. Property located in designated FW(Floodway) District? Yes No (If yes, certification and
engineering calculations shall be provided by a registered Professional Engineer(P.E.)that the property use or
structure, when built,will not cause any increase in floodwater levels during an intermediate regional flood
(100-year flood) and will not limit or restrict the flow capacity of the floodway.)
4. Is the property located in a designated FP-1 (100-yr Floodplain) or FP-2 (500-yr Floodplain) District?
Yes No
Signature: Owner or Authorized Agent Date Signature: Owner or Authorized Agent Date
•(If an Authorized Agent signs,a letter of authorization from all fee owners must be included with the application.If a corporation is the fee owner,
notarized evidence must be included showing the signatory has to legal authority to sign for the corporation.)
Updated 03-13-2008 6
STATE OF COLORADO of `°10
COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT re
Water Quality Control Division—Stormwater Program r +
*1876*
• STORMWATER DISCHARGES ASSOCIATED WITH CONSTRUCTION ACTIVITY
GENERAL PERMIT APPLICATION
and
STORMWATER MANAGEMENT PLAN PREPARATION GUIDANCE
Revised 3/2009
Contact information
Colorado Department of Public Health and Environment Telephone: (303)692-3517
Water Quality Control Division—Stormwater Program Email: cdphe.wgstormAstate.co.us
WQCD-Permits-B2 Web Page: www.cdphe.state.co.us/wq/PermitsUnit
4300 Cherry Creek Drive South
Denver,Colorado 80246-1530
CONTENTS
Applicability
Instructions for Completing the Application
General Permit Application
Appendix A—Preparing a Stormwater Management Plan(SWMP)
APPLICABILITY
es application is for use by all entities engaged in construction activities to obtain coverage under the general
permit for Stormwater Discharges Associated with Construction Activities (the Stormwater Construction Permit).
Construction activity refers to ground surface disturbing activities, which include,but are not limited to,clearing,
grading, excavation, demolition, installation of new or improved haul roads and access roads, staging areas,
stockpiling of fill materials, and borrow areas. Construction does not include routine maintenance to maintain
original line and grade, hydraulic capacity, or original purpose of the facility.
Stormwater Construction Permit coverage is required by State and Federal regulations for stormwater discharged
from any construction activity that disturbs at least 1 acre of land (or is part of a larger common plan of
development or sale that will disturb at least 1 acre). A "common plan of development or sale" is a site where
multiple separate and distinct construction activities may be taking place at different times on different schedules,
but still under a single plan. This includes phased projects, projects with multiple filings or lots, and projects in a
contiguous area that may be unrelated but still under the same contract. If the project is part of a common plan of
development or sale, the disturbed area of the entire plan must be used in determining permit requirements, and all
portions of the project must be covered.
NOTES:
Stormwater Management Plan Preparation Guidance—The guidance, available as Appendix A to this
application, has been revised and updated.
Additional Guidance—Additional information, including further discussion on permittee and operator liability, is
available in the Stormwater Fact Sheet—Construction, available from the Division's web site at
www.cdphe.state.co.us/wq/PermitsUnit. If you have questions on completing this application, you may contact the
'sion at cdphe.wqstorm@state.co.us or(303)692-3517.
Instructions—Page 1 of 5 Revised 3/2009
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wo/oermitsunit
INSTRUCTIONS
A) Submitting the Application
Application Due Date: At least ten days prior to the anticipated start of construction,the owner or operator of the
'Instruction activity must submit an application as provided by the Water Quality Control Division(Division).
is form may be reproduced,and is also available from the Division's web site(see previous page for
address/contact information). Applications received by the Division are processed, and a permit certification and
other relevant materials will be sent to the attention of the legally responsible person (Item 9 on the application
form).
Permit Fee: Do not send any payment with this application. You will be billed once you are covered under a
permit. Current permit fees can be obtained from the Division's web site at
www.cdphe.state.co.us/wq/PermitsUnit.
Application Completeness: The application must be completed accurately and in its entirety or the application
will be deemed incomplete—processing of the application will not begin until all required information is received.
One original copy of the completed application(no faxes or e-mails)must be submitted to the Division to initiate
the application process(see page 1 above for address/contact information).
Do not include a copy of the Stormwater Management Plan, unless requested by the Division.
B)Who May Apply For and Maintain Permit Coverage
The Permit applicant must be a legal entity that meets the definition of the owner and/or operator of the
construction site, in order for this application to legally cover the activities occurring at the site. The applicant
must have day-to-day supervision and control over activities at the site and implementation of the SWMP.
Although it is acceptable for the applicant to meet this requirement through the actions of a contractor,as
discussed in the examples below,the applicant remains liable for violations resulting from the actions of their
contractor and/or subcontractors. Examples of acceptable applicants include:
• • Owner or Developer-An owner or developer who is operating as the site manager or otherwise has
supervision and control over the site,either directly or through a contract with an entity such as those listed
below.
• General Contractor or Subcontractor-A contractor with contractual responsibility and operational
control (including SWMP implementation)to address the impacts construction activities may have on
stormwater quality.
• Other Designated Agents/Contractors- Other agents, such as a consultant acting as construction manager
under contract with the owner or developer, with contractual responsibility and operational control
(including SWMP implementation)to address the impacts construction activities may have on stormwater
quality.
An entity conducting construction activities at a site may be held liable for operating without the necessary
permit coverage if the site does not have a permit certification in place that is issued to an owner and/or
operator. For example, if a site (or portion of a site) is sold or the contractor conducting construction activities
changes,the site's permit certification may end up being held by a permittee (e.g.,the previous owner or
contractor)who is no longer the current owner and/or operator. In this case,the existing permit certification
will no longer cover the new operator's activities, and a new certification must be issued,or the current
certification transferred.
Utilities, Other Subcontractors, etc.: A separate permit certification is not needed for subcontractors, such as
utility service line installers,where the permittee or their contractor is identified as having the operational
control to address any impacts the subcontractor's activities may have on stormwater quality. Although
separate permit coverage may not be needed in some cases, these entities are not exempt from the stormwater
regulations for all of their projects and may still be held liable if their activities result in the discharge of
• pollutants.
Leases: When dealing with leased land or facilities, the lessee shall be considered the"owner" for the
purposes of stormwater permitting if they are responsible for the activities occurring at the site.
Instructions—Page 2 of 5 Revised 3/2009
Water Quality Control Division—Stormwater Program www.cdohe.state.co.us/wQ/permitsunit
C) Permitting for Developments with Multiple Owners and/or Operators
For situations where multiple entities meet the definition of owners and/or operators for different portions of a
development(e.g., a single development with multiple lots owned and operated by separate entities), it is essential
"Pat the permittees, owners,and operators at the site correctly follow the guidance on who may apply for coverage
nder the Stormwater Construction Permit(see Part B,above).
When a portion of a permitted site is sold to a new owner, a permit certification must be in place that is held by an
entity meeting the definition of owner and/or operator of that sold lot. This may be accomplished in one of the
following ways:
• Coverage Under the Existing Certification—Activities at the sold area may continue to be covered under an
existing permit certification for the project if the current permittee meets the definition of operator for the sold
area. To meet the definition of operator,the current permittee must have contractual responsibility and
operational control to address the impacts that construction activities at the sold area may have on stormwater
runoff(including implementation of the SWMP for the sold area). Therefore,a legally binding agreement must
exist assigning this responsibility to the current permit holder on behalf of the new owner and/or operator for the
sold area. It is not necessary to notify the Division in such case. However,documentation of the agreement must
be available upon request,and the SWMP must be maintained to include all activities covered by the Stormwater
Construction Permit
• New Certification Issued—Reassignment—A new permit certification may be issued to the new owner and/or
operator of the sold area. The existing permittee and the new owner and/or operator must complete the
Reassignment Form(available from the Division's web page, see page 1)to remove the sold area from the
existing permit certification and cover it under a certification issued to the owner and/or operator of the sold area.
Both entities must have SWMPs in place that accurately reflect their current covered areas and activities.
A more detailed explanation is available in the Stormwater Fact Sheet—Construction, available from the Division's
web site (see page 1).
•Instructions for the Application Form
Item 1 -Applicant Information: Provide the company name, address,phone number, email address for applicant,
and local contact information for the project. Indicate whether the applicant is the owner, the developer, or
a contractor.
Item 2-Location of the Construction Site: Provide the following information:
• Street Address—Provide the address of the construction site. If an exact address is not available you
may use an approximate address, the nearest intersection or boundary streets including directional
identifiers(e.g., "S. of Park St. between 5th Ave. and 10th Ave.", or"W. side of C.R. 21, 3.25 miles N. of
Hwy 10") or other identifying information. A street name without an address, intersection, mile marker,
or other identifying information describing the location of the project is not adequate. For linear
projects,the route of the project should be described as best as possible with the location more
accurately indicated by a map (see Item 3).
• Project Name,City, and County—If the project is located within the unincorporated portion of a
county,write"unincorporated" in the space provided for the city name.
• Latitude/Longitude- For the approximate center point of the property,to the nearest 15 seconds. The
latitude and longitude must be provided as either degrees, minutes,and seconds,or in decimal degrees
with three decimal places. This information may be obtained from a variety of sources, including:
o Surveyors or engineers for the project should have, or be able to calculate,this information.
o EPA maintains a web-based siting tool as part of their Toxic Release Inventory program that uses
interactive maps and aerial photography to help users get latitude and longitude. The siting tool can
be accessed at www.epa.gov/tri/report/siting_tool/index.htm
• o U.S. Geological Survey topographical map(s), available at area map stores.
o Using a Global Positioning System (GPS) unit to obtain a direct reading.
Note the latitude/longitude required above is not the directional degrees, minutes, and seconds
provided on a site legal description to define property boundaries.
Instructions—Page 3 of 5 Revised 3/2009
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/we/permitsunit
Item 3-Legal Description or Map: One of these two items must be provided:
• Legal Description of the entire site covered by the application. The description must include
subdivision(s), block(s), and lot(s) (providing the metes and bounds or just the township/section/range, is
• not adequate).This information should be available for subdivided properties from documents submitted
to or maintained by the city or county, such as the subdivision plat or deed. If this information is not
available, a map must be submitted.—or—
• Site Map that defines the boundaries of the site covered by the application. The level of detail that must
be provided will depend on the nature of the project and must be adequate so that it can be determined
during a field audit what construction activities are covered under the issued certification. For typical
developments within a specific surveyed property,a map that clearly shows the property boundaries
should be obtainable. For projects located in areas with adjacent construction areas that will not be
covered by the application (such as multi-lot developments with multiple owners/operators),this detail is
essential. However, for projects such as road or utility projects,where providing this detail may not be
feasible or necessary to distinguish the project from adjacent activities, a less detailed map showing the
approximate area is adequate. Maps must have a minimum scale of 1:24000(the scale of a USGS 7.5
minute map). Maps must be folded to 8%2 x 11 inches. Do not submit grading plans or other blueprints
as the site map or the application will be rejected. This is not the same as the map required in the SWMP
(see Appendix A).
Item 4-Area of Construction Site: Provide both the total area of the construction site, and the area that will
undergo disturbance, in acres. Note: aside from clearing, grading and excavation activities,disturbed
areas also include areas receiving overburden(e.g., stockpiles), demolition areas, and areas with heavy
equipment/vehicle traffic and storage that disturb existing vegetative cover(see construction activity
description under the APPLICABILITY section on page 1).
If the project is part of a larger common plan of development or sale(see the definition under the
• APPLICABILITY section on page 1), the disturbed area of the total plan must also be included.
Item 5-Nature of Construction Activities: Check the appropriate box or boxes, or if the descriptions provided
do not fit the project, provide a brief description that indicates the general nature of the construction
activities for which permit coverage is being requested. A more detailed description of the project must be
included in the Stormwater Management Plan (see Item 8).
Item 6-Anticipated Construction Schedule: Provide the current estimated start and final stabilization dates for
the construction project as follows:
Constractlon Start Date-This is the day you expect to begin ground disturbing activities, including
grubbing, stockpiling, excavating, demolition, and grading activities.
• Fr)ra&Stabilizatlon Date- in terms of permit coverage,this is when the site is finally stabilized. This
means that all ground surface disturbing activities at the site have been completed, and all disturbed
areas have been either built on, paved, or a uniform vegetative cover has been established with an
individual plant density of at least 70 percent of pre-disturbance levels. Permit coverage must be
maintained until the site is finally stabilized. Even if you are only doing one part of the project,the
estimated final stabilization date must be for the overall project. If permit coverage is still required
once your part is completed,the permit certification may be transferred or reassigned to a new
responsible entity(s).
Item 7- Receiving Water(s): Identify the receiving water of the stormwater from your site. Receiving waters are
any waters of the State of Colorado. This includes all water courses,even if they are usually dry. If
• stormwater from the construction site enters a ditch or storm sewer system, identify that system and
indicate the ultimate receiving water for the ditch or storm sewer. Note: a stormwater discharge permit
does not allow a discharge into a ditch or storm sewer system without the approval of the owner/operator
of that system.
Instructions—Page 4 of 5 Revised 3/2009
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
Item 8- Stormwater Management Plan (SWMP)Certification: The certification of completion of a SWMP
must be signed by the applicant or their authorized agent. Appendix A contains the requirements for the
SWMP during the period of construction(as listed in the Stormwater Construction Permit). Submittal of
• the SWMP with the application is not required; however, it must be developed and implemented, and
kept at the construction site. The Division reserves the right to request the SWMP at any time.
Item 9- Signature of Applicant: The applicant must be either the owner and/or operator of the construction site.
Refer to Part B of the instructions for additional information. The application must be signed by the
applicant to be considered complete. In all cases, it shall be signed as follows:
a) In the case of corporations, by a principal executive officer of at least the level of vice-president or his
or her duly authorized representative, if such representative is responsible for the overall operation of
the facility from which the discharge described in the application originates.
b) In the case of a partnership, by a general partner.
c) In the case of a sole proprietorship,by the proprietor.
d) In the case of a municipal, state, or other public facility,by either a principal executive officer, ranking
elected official, or other duly authorized employee if such representative is responsible for the overall
operation of the facility from which the discharge described in the form originates.
241 This certification includes an acknowledgment that the applicant understands that the permit
coverage, and therefore the applicant's liability,will be for the entirety of the construction project
described and applied for,until such time as the application is amended or the certification is
transferred,inactivated,or expired.
•
•
Instructions—Page 5 of 5 Revised 3/2009
GENERAL PERMIT APPLICATION For Agency Use Only C O R-0 3
STORMWATER DISCHARGES ASSOCIATED
WITH: CONSTRUCTION ACTIVITY Date Received: / _/
Month Day Year
(Permit No.COR-030000) Billing Code: 09 9B 00
• ALL APPLICANTS MUST FOLLOW PART D OF THE INSTRUCTIONS TO COMPLETE THIS FORM
Please print or type. All items must be completed accurately and in their entirety,or the application will be deemed incomplete
and returned to the applicant. Processing of the application will not begin until all* REQUIRED information is received.
Please refer to the instructions for information about the required items. Original Wet Ink signatures for Items 8 and 9 are
required.
I. Name and address of the permit applicant(legally responsible entity):
*Company Name
*Mailing Address
*City, State and Zip Code
*Legally Responsible Person(application signer)
*Title
*Legally Responsible Person E-mail Address
*Phone Number Who is applying? Owner El Developer Q Contractor ID
*Local Contact(familiar with facility)
*Title *Phone Number
*Local Contact E-mail Address
2. "IL ocation of the construction site:
*Name of plan,project, or development
*Street Address(or cross streets)
*City(if unincorporated, so indicate) *County *Zip Code
*Latitude/Longitude (approximate center of the site)—use one of the following formats:
Latitude / / Longitude / / (e.g.,39°42'11", 104°55'57")
degrees minutes seconds degrees minutes seconds
—or—
Latitude Longitude (e.g.,39.703°, 104.933°')
degrees(to 3 decimal places) degrees(to 3 decimal places)
3. * Legal Description or Map
❑ Legal Description per instructions(NOT METES AND BOUNDS)
Subdivision(s) Lot(s) Block(s)
-or-
El Map Indicating Boundaries of Disturbed Area- Maps must be folded to 8'/2 x 11 inches.
t. * Area of the construction site:
Total area of project site(acres)
rea of project site to undergo disturbance(acres)
otal disturbed area of Larger Common Plan of Development or Sale, if applicable(i.e.,total, including all phases,
filings, lots, and infrastructure not covered by this application)
4pplication-Page 1 of 2 *REQUIRED ENTRY Revised 3/2009
5. *Nature of the construction activity:
Check the appropriate box(s)or provide a brief description that indicates the general nature of the construction activities.
(The full description of activities must be included in the Stormwater Management Plan.)
• Single Family Residential Development
❑ Multi-Family Residential Development
Ei Commercial Development
ID Oil and Gas Production and/or Exploration(including pad sites and associated infrastructure)
Highway/Road Development(not including roadways associated with commercial or residential development)
DOther,Describe: —
*Anticipated construction schedule:
Construction Start Date: / / Final Stabilization Date:__/__/__
month day year month day year
*The name of the receiving waters(s).(If discharge is to a ditch or storm sewer, also include the name of the ultimate
receiving water):
[STOP! A Stormwater Management Plan (see Appendix A)must be completed prior to signing the following
certifications!
* Stormwater Management Plan Certification:
"I certify under penalty of law that a complete Stormwater Management Plan,as described in Appendix A of this
lication,has been prepared for my activity. Based on my inquiry of the person or persons who manage the
stem, or those persons directly responsible for gathering the information,the Stormwater Management Plan is,to the
best of my knowledge and belief,true, accurate, and complete. I am aware that there are significant penalties for falsely
certifying the completion of said SWMP, including the possibility of fine and imprisonment for knowing violations."
Signature of Legally Responsible Person(submission must include original wet ink signature) Date Signed
Name(printed) Title
* Signature of Applicant
"I certify under penalty of law that I have personally examined and am familiar with the information submitted in this
application and all attachments and that, based on my inquiry of those individuals immediately responsible for obtaining
the information, I believe that the information is true,accurate and complete. I am aware that there are significant
penalties for submitting false information, including the possibility of fine or imprisonment.
"I understand that submittal of this application is for coverage under the State of Colorado General Permit for
Stormwater Discharges Associated with Construction Activity for the entirety of the construction site/project
described and applied for,until such time as the application is amended or the certification is transferred,
inactivated,or expired."
Signature of Legally Responsible Person(submission must include original wet ink signature) Date Signed
erne(printed) Title
)NOT include copy of Stormwater Management Plan
)NOT include payment—an invoice will be sent after certification is issued
Application -Page 2 of 2 * REQUIRED ENTRY Revised 3/2009
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
APPENDIX A
SWMP GUIDANCE
• PREPARING A STORMWATER MANAGEMENT PLAN (SWMP)
Stormwater Construction General Permit
Contents
A. INTRODUCTION page 2
B. GENERAL GUIDANCE 2
• BMPs 2
Special topic:
Erosion Control BMPs, Sediment Control BMPs 3
• Implementation 3
• Common Sense Approach 3
• SWMP Items,Format 3
• Existing Controls 3
• Control Implemented by Other Parties 3
• SWMP Availability 4
C. STORMWATER MANAGEMENT PLAN REQUIRMENTS 4
C.l SWMP GENERAL REQUIREMENTS 4
C.2 SWMP CONTENTS—Narrative Site Description 5
C.3 SWMP CONTENTS—Site Map 6
Special topic: Using Construction Plans,Plans Developed to Meet Local
Stormwater Requirements,or Other Plans 6
C.4 SWMP CONTENTS—Stormwater Management Controls 7
• a. SWMP Administrator 7
b. Identification of Potential Pollutant Sources 8
c. Best Management Practices(BMPs) for Stormwater Pollution Prevention 10
i) Selecting and locating appropriate BMPs 10
ii) Specific BMPs for Material Handling and Spill Prevention 10
Special topics:
•BMP location 11
•Ensuring BMPs are under the Control of the Permittee 11
•Protecting Waters of the United States 11
iii) Documenting Selected BMPs in the SWMP(including phasing of BMP implementation)12
Special topic: BMP description: Level of detail 12
iv) Non-Stormwater Discharges 12
• Concrete Washout water 12
• Construction Dewatering water 12
v) Stormwater Dewatering: 13
d. Revising BMPs and the SWMP 13
C.5 SWMP CONTENTS—Final Stabilization and Long-term Stormwater Management 14
Special topic: Inactivation of permit coverage 14
Special topic: Use of Permanent Detention Ponds as BMPs during Construction 15
C.6 SWMP CONTENTS—Inspection and Maintenance Procedures 15
a. Inspection Schedules 15
b. Inspection Procedures 15
c. BMP Maintenance/Replacement and Failed BMPs 16
• d. Record Keeping and Documenting Inspections 16
Appendix A-Page 1 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
D. ADDITIONAL SWMP AND BMP RESOURCES 17
D.1.RESOURCES—BMP Design and Implementation 17
a. BMP Design Criteria Manuals: 17
• b. General BMP Selection and Design Guidance 18
c. Special Applications 18
D.2. RESOURCES—Example Management Plans 19
D.3. RESOURCES—Training 19
A. INTRODUCTION
This guidance document is designed to help you develop a Stormwater Management Plan (SWMP) for your
construction project,as required for compliance with the CDPS general permit for Stormwater Discharges Associated
with Construction Activities (the Stormwater Construction Permit). It explains what each of the SWMP requirements
means,and gives some options for you to consider in developing Best Management Practices(BMPs)that are best
suited to your site during construction.
This guidance document primarily addresses the SWMP requirements in the Stormwater Construction Permit. Other
requirements and limitations, such as records retention,reporting, inspections, etc., are detailed in the Stormwater
Construction Permit itself. Also note that the SWMP and the Stormwater Construction Permit only cover discharges of
stormwater.
Stormwater Management Plan(SWMP) Goal: To identify possible pollutant sources that may contribute
pollutants to stormwater,and identify Best Management Practices (BMPs)that, when implemented, will reduce or
eliminate any possible water quality impacts. The SWMP must be completed and implemented at the time the
project breaks ground,and revised as construction proceeds,to accurately reflect the conditions and practices at
the site.
ituction activities use and produce many different kinds of pollutants which may impact water quality. The
main pollutant of concern at construction sites is sediment. Grading activities remove grass,rocks,pavement and other
protective ground covers, resulting in the exposure of underlying soil to the elements. The soil is then easily picked up
by wind and/or washed away by rain or snowmelt. For example, sediment runoff rates from construction sites are
typically 10 to 20 times greater than those from agricultural lands,and 1,000 to 2,000 times greater than those of forest
lands. During a short period of time,construction activity can contribute more sediment to streams than would normally
be deposited over several decades, causing physical and biological harm to our State's waters. The added sediment
chokes the river channel and covers the areas where fish spawn
and plants grow. Excess sediment can cause a number of other Uncontrolled storm water discharges from
problems for waterbodies, such as increased difficulty in areas of urban development and construction
filtering drinking water, and clouding the waters which can kill activity negatively impact receiving waters by
plants growing in the river and suffocate fish. A number of changing the physical,biological, and chemical
pollutants, such as nutrients, are absorbed onto sediment composition of the water,resulting in an
particles and also are a source of pollution associated with unhealthy environment for aquatic organisms,
sediment discharged from construction sites. wildlife, and humans.
In addition, construction activities often require the use of toxic or hazardous materials such as petroleum products,
fertilizers, pesticides and herbicides, and building materials such as asphalt, sealants and concrete, which may pollute
stormwater. These materials can be harmful to humans, plants and aquatic life.
B. GENERAL GUIDANCE
BMPs: Best Management Practices (BMPs)encompass a wide range of erosion and sediment control practices, both
st ural and non-structural in nature,that are intended to reduce or eliminate any possible water quality impacts from
s ater leaving a construction site. The individual BMPs appropriate for a particular construction site are largely
dependant of the types of potential pollutant sources present,the nature of the construction activity, and specific-site
conditions.
Appendix A-Page 2 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
NonstruclaralfMPs,such as preserving natural vegetation,
preventive maintenance and spill response procedures, Best Management Practices to prevent the
Itaules of activities,prohibition of specific practices, erosion and discharge of sediment typically
e tion, and other management practices are mainly include:
operational or managerial techniques. 1. Erosion Control BMPs
Practices to prevent the erosion of soil.
SlruclaralB&tFs include treatment processes and practices
ranging from diversion structures and silt fences,to retention Examples:
ponds and inlet protection. • minimizing the amount of disturbed soil
through phasing, temporary stabilization, or
Most of the BMPs referenced here are widely used in the leaving existing vegetation
construction industry. They generally involve a simple and low • diverting runoff around disturbed areas
cost approach, and can be very effective when properly 2. Sediment Control BMPs
installed and maintained. Practices to remove sediment from runoff.
The Stormwater Construction Permit requires the use of a self- Examples:
•
designed SWMP. This plan is based on the use of BMPs. For retaining stormwater in ponds or behind silt
construction sites,there are several types of BMPs: those that fence to settle out sediment
prevent erosion, those that prevent construction materials from • filtering stormwater through filter fabric on
introducing pollutants to stormwater, and those that remove inlets
sediment and other pollutants before they can be discharged
(see box, to right).
Implementation: The SWMP focus is primarily on controls used during ground surface disturbing activities. This
focus means that many sediment control BMPs, such as silt fence and inlet protection, must be installed before
disturbing activities begins, not after.
it
Sense Approach: Your SWMP is intended to be a usable document, not a paper exercise. Therefore, do not
i e practices that may sound good, but are unreasonable or not feasible for your site. Failure to implement your
SWMP, even if the BMPs listed do not make sense,puts you in automatic violation of the Stormwater Construction
Permit. For example, a blanket statement that runoff from all disturbed areas will be controlled by silt fences, even if
the slope or channels are too steep/narrow for this particular BMP, would be unreasonable.
On the other hand, if a particular BMP is listed in the SWMP, but then later turns out to be impractical or ineffective,
the SWMP must be amended to reflect the changes/improvements made.
SWMP Items,Format: When preparing your plan, make sure to address each item included in this guidance. If it
is not applicable to your site, briefly explain why. A simple "Not Applicable" is not enough. Failure to address each
item is a violation of the Stormwater Construction Permit.
In addition,your SWMP should follow the same format as the SWMP requirements listed in Section C, below. That is,
even if you are using an existing document(such as plans and specs)that addresses the required SWMP items,you
should include a cross-reference for each of the SWMP items that indicates where it can be found in your existing
document. You must be able to provide all required components of the SWMP to a State, EPA, or local agency
inspector at your site, so the location and format of the information must be clear to the site personnel in charge of
SWMP implementation.
Existing Controls: Note that the SWMP should include any existing stormwater controls at your site, not just new or
proposed ones. It can also include any erosion, sediment or drainage controls which are required by other regulations,
such as local erosion and sediment control ordinances, if you are also using them to meet the SWMP requirements.
Control Implemented by Other Parties: A permittee will often have to rely on controls implemented by other parties
to ure adequate management of stormwater runoff. For example, if a permit certification is obtained to cover a lot in
a r development,the permittee may need to rely on BMPs implemented by an entity in charge of the larger
development, such as street sweeping, inlet protection, or a water quality detention pond that treats runoff from several
different lots. In such situations, the BMPs implemented by the other party must be fully addressed by the permittee's
Appendix A-Page 3 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
SWMP, and written agreements must exist between the permittee and the party implementing the BMP(s)to ensure
adequate operation and maintenance of those BMPs. Additional guidance is available in the Stormwater Fact Sheet for
Construction,available from the Division's web site at www.cdphe.state.co.us/wq/PermitsUnit.
!1P Availability: A copy of the SWMP must be kept on site, readily available to the operator, and to Division or
EPA personnel for review during inspections. City, county, and local agencies may also request the SWMP as part of a
local oversight program. If an office location is not available at the site, the SWMP must be managed so that it is
available at the site when construction activities are occurring(e.g.,by keeping the SWMP in a superintendent's
vehicle.)
C. STORMWATER MANAGEMENT PLAN REQUIRMENTS
In this section, the text in italics, and marked with the Permit banner, is quoted directly from the Stormwater
Construction Permit. The text in standard typeface is provided as guidance in the preparation of your SWMP. The
references (Part I.C, for example) correspond to the location of the item in the Stormwater Construction Permit, unless it
specifically references a section in this document.
C.1 SWMP GENERAL REQUIREMENTS
Part LB Stormwater Management Plan (SWMP) - General Requirements
I. A SWMP shall be developed for each facility covered by this permit. The SWMP shall be prepared in
accordance with good engineering, hydrologic and pollution control practices. (The SWMP need not be prepared
by a registered engineer.)
2. The SWMP shall:
a) Identify all potential sources of pollution which may reasonably be expected to affect the quality of
stormwater discharges associated with construction activity from the facility;
b) Describe the practices to be used to reduce the pollutants in stormwater discharges associated with
construction activity at the facility;and ensure the practices are selected and described in accordance with good
engineering practices, including the installation, implementation and maintenance requirements; and
c) Be properly prepared, and updated in accordance with Part I.D.5.c, to ensure compliance with the terms
and conditions of this permit.
3. Facilities must implement the provisions of the SWMP as written and updated,from commencement of
construction activity until final stabilization is complete, as a condition of this permit. The Division reserves the right
to review the SWMP, and to require the permittee to develop and implement additional measures to prevent and
control pollution as needed.
4. The SWMP may reflect requirements for Spill Prevention Control and Countermeasure (SPCC)plans under
section 311 of the CWA, or Best Management Practices (BMPs)Programs otherwise required by a separate CDPS
permit, and may incorporate any part of such plans into the SWMP by reference,provided that the relevant sections
of such plans are available as part of the SWMP consistent with Part I.D.5.b.
For any sites with permit coverage before June 30, 2007, the permittee's SMWP must meet the new SWMP
requirements as summarized in Section 11.1 of the rationale. Any needed changes must be made by October 1, 2007.
The General Requirements section provides the broad expectations for the preparation, contents and implementation of a
SWMP. The specific items that must be included in the SWMP are addressed in the SWMP Contents sections below.
•
Appendix A-Page 4 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
C.2 SWMP CONTENTS—Narrative Site Description
Part I.C.1 Stormwater Management Plan (SWMP)—Contents: Site Description
e SWMP shall include the following items, at a minimum:
Site Description. The SWMP shall clearly describe the construction activity, to include:
a) The nature of the construction activity at the site.
b) The proposed sequence for major activities.
c) Estimates of the total area of the site, and the area and location expected to be disturbed by clearing,
excavation, grading, or other construction activities.
d) A summary of any existing data used in the development of the site construction plans or SWMP that
describe the soil or existing potential for soil erosion.
e) A description of the existing vegetation at the site and an estimate of the percent vegetative ground cover.
J) The location and description of all potential pollution sources, including ground surface disturbing
activities (see Part I.A.2.b), vehicle fueling, storage offertilizers or chemicals, etc.
g) The location and description of any anticipated allowable sources of non-stormwater discharge at the site,
e.g., uncontaminated springs, landscape irrigation return flow, construction dewatering, and concrete
washout.
h) The name of the receiving water(s)and the size, type and location of any outfall(s). If the stormwater
discharge is to a municipal separate storm sewer system, the name of that system, the location of the storm
sewer discharge, and the ultimate receiving water(s).
This part requires a narrative description of the overall scope and physical characteristics of the project, as follows:
a) Include a description of the construction activities at the site (e.g.,type of project, a summary of the grading
tillittvities, installation of utilities,paving, excavation, landscaping,etc)and the final disposition of the property.
escribe the sequence of events involved in the construction project, such as grading, excavation, etc.
c) This information, which is also required in the application, is useful in determining the extent of control measures
needed.
d) Data describing soils or erosion potential will typically not be needed. This information only needs to be included if
it was used in development of the SWMP, such as for BMP design.
e) It is necessary to include the percentage of existing vegetative ground cover in order to determine, after
construction,when the site has been finally stabilized. See Part I.C.4 of the Stormwater Construction Permit(also
Section C.5 of this document), for final stabilization criteria. Final stabilization of the site is necessary before
coverage under the Stormwater Construction Permit can be terminated.
t) Describe all materials and activities at the site that may have an impact on stormwater. These may include such
things as: ground disturbing activities; equipment or vehicle washing; fertilizers, chemicals,or other materials
storage; vehicle maintenance or fueling; waste incineration,treatment, storage or disposal; haul roads; off-site
vehicle tracking; loading/unloading areas, etc.
g) Will there be any discharge from the project site during construction that is not from stormwater? If so, describe the
source and how it will be handled.
h) The receiving water information is also required in the permit application. For example, "runoff from the east side
of the site will go to a roadside ditch which discharges to Jimmy Smith Gulch; runoff from the west side of the site
will go to an unnamed tributary to Westerly Creek."
•
Appendix A-Page 5 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
C.3 SWMP CONTENTS—Site Map
Part I.C,2 Stormwater Management Plan (SWMP)—Contents: Site Map
e SWMP shall include a legible site map(s), showing the entire site, identifying:
a) construction site boundaries;
b) all areas of ground surface disturbance;
c) areas of cut and fill;
d) areas used for storage of building materials, equipment, soil, or waste;
e) locations of dedicated asphalt or concrete batch plants;
J) locations of all structural BMPs; •
g) locations of non-structural BMPs as applicable; and
h) locations of springs, streams, wetlands and other surface waters.
A site map must be developed for each construction project. The site map must show those items listed above. It does
not need to be drawn to scale, but it should be legible and easy to read. Maps that are part of the construction plans,
such as a grading plan, are a good base for developing the site map, if they are amended to include all required
information as discussed below. Local municipalities may also have maps suitable as bases to begin mapping
procedures. If no other suitable base maps are available, one must be developed. Regardless of the source of the base
map, the site map needs to be of suitable scale to show the construction portion of the site and the features within it.
Using Construction Plans,Plans Developed to Meet Local Stormwater Requirements, or Other Plans:
In many cases, some of the information required for the SWMP will also be included in items such as construction
plans, documents developed for a local stormwater program, material management plans, etc.These materials may
be used to meet the SWMP requirements, if they are amended and/or supplemented to include all required
rmation. If the SWMP will be incorporated into the construction plan, all of the required narrative
ormation must also be included in the plans, or developed as a separate document. If a separate document is
used for some of the information not in the construction plans, or if the information will be included in several
locations,the permittee must still be able to provide all required components of the SWMP to a State or EPA
inspector. If this approach is used, it is highly recommended that an index be provided that references the
location(s) of all information required for the SWMP.
In addition to the items specifically mentioned in the permit, above, it is useful to also indicate on the map the
following:
• Drainage basins for each outfall—Field inspection can usually accomplish this task with acceptable accuracy. Look
for high areas such as crests of hills,parking lots, roads, etc., which would form the division between drainages.
Gullies and swales are indicators of stormwater flow direction. Obviously, if runoff is observed during a storm,
most uncertainties can be eliminated. The drainage areas shown should include the portions of the site where the
activities described in I.C.I.f of the Stormwater Construction Permit(see the permit language in Section C.2, above)
occur, as well as those portions (such as upslope areas)contributing stormwater that mixes with runoff from the
construction area.
• Surface water bodies—Mark on the site map any surface water bodies, including dry water courses, lakes, streams,
springs, wetlands, detention ponds, roadside or irrigation ditches, etc. These do not necessarily need to be within
the construction portion of the site, but may be adjacent to it or impacted by stormwater runoff. Also include any
existing storm sewers.
• Existing and planned structural stormwater pollution control measures—Show on the map the location of any
structural stormwater pollution control measures, such as detention ponds, diversion ditches, covered material
IFrage areas, fuel farm secondary containment structures, etc. Refer to the guidance on how to"Document
l ected BMPs in the SWMP" in Section C.4, below.
• Areas where construction activities take place—for those construction activities identified in Part 1.C.I.a of the
Stormwater Construction Permit(see the permit language in Section C.2, above).
Appendix A-Page 6 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
In addition,other features could be included to make the SWMP a more comprehensive and usable plan. For example,
a ter section of the SWMP includes requirements for material handling and spill prevention procedures,which could
e a site map showing where materials are stored. By including materials handling, loading and storage areas on
t ite map, all information would be in one place on a single base map. Also, including such items as site entrance(s),
vehicle parking areas and direction of stormwater flow on the site map adds to its overall utility
Refer to Section D of this guidance for sources of sample maps, such as the Douglas County Grading, Erosion,and
Sediment Control (GESC)Manual and the Construction Industry Compliance Assistance Center.
C.4 SWMP CONTENTS—Stormwater Management Controls
IPart I.C.3 Stormwater Management Plan (SWMP)—Contents: Stormwater Management Controls
The SWMP must include a description of all stormwater management controls that will be implemented as part of the
construction activity to control pollutants in stormwater discharges. The appropriateness and priorities of
stormwater management controls in the SWMP shall reflect the potential pollutant sources identified at the facility.
The description of stormwater management controls shall address the following components, at a minimum:
This is the key part of the SWMP—a narrative description of the appropriate stormwater management controls for the
permitted site. As further addressed below, in many cases it may be necessary to supplement the narrative description
with technical drawings in order to accurately communicate the design standards for certain structural BMPs.
Part I.C.3 Stormwater Management Plan (SWMP)— Contents: SWMP Administrator
) SWMP Administrator- The SWMP shall identify a specific individual(s),position or title who is responsible for
developing, implementing, maintaining, and revising the SWMP. The activities and responsibilities of the
administrator shall address all aspects of the facility's SWMP.
a. SWMP Administrator: The SWMP Administrator can be an individual(s),position or title—this entity is
responsible for developing, implementing, maintaining, and revising the SWMP. Remember that the SWMP
Administrator is the contact for all SWMP-related issues and is the person responsible for its accuracy,
completeness, and implementation. Therefore, the SWMP Administrator should be a person with authority to
adequately manage and direct day-to-day stormwater quality management activities at the site.
•
Appendix A-Page 7 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
Part I.C.3 Stormwater Management Plan (SWMP)—Contents: Identification of Potential Pollutant Sources
b) Identification of Potential Pollutant Sources-All potential pollutant sources, including materials and activities,
at a site must be evaluated for the potential to contribute pollutants to stormwater discharges. The SWMP
shall identify and describe those sources determined to have the potential to contribute pollutants to
stormwater discharges, and the sources must be controlled through BMP selection and implementation, as
required in paragraph (c), below.
At a minimum, each of the following sources and activities shall be evaluated for the potential to contribute
pollutants to stormwater discharges, and identified in the SWMP if found to have such potential:
1) all disturbed and stored soils;
2) vehicle tracking of sediments;
3) management of contaminated soils;
4) loading and unloading operations;
5) outdoor storage activities (building materials,fertilizers, chemicals, etc.);
6) vehicle and equipment maintenance and fueling;
7) significant dust or particulate generating processes;
8) routine maintenance activities involving fertilizers,pesticides, detergents,fuels, solvents, oils, etc.;
9) on-site waste management practices (waste piles, liquid wastes, dumpsters, etc.);
10) concrete truck/equipment washing, including the concrete truck chute and associated fixtures and
equipment;
11) dedicated asphalt and concrete batch plants;
12) non-industrial waste sources such as worker trash and portable toilets; and
13) other areas or procedures where potential spills can occur.
•Identification of Potential Pollutant Sources: The first thing to do is evaluate all pollutant sources and
tivities at the site for the potential to contribute pollutants to stormwater discharges. Part I.C.3.b of the
Stormwater Construction Permit(see permit language above) lists 13 pollutant sources that must be evaluated for
the reasonable potential to contribute pollutants to runoff. During the evaluation, consider the following types of
conditions that might affect the potential for a pollutant source to contribute pollutants to stormwater:
• the frequency of the activity(i.e., does it occur every day, or just once a month; can it be scheduled to occur
only during dry weather?);
• characteristics of the area where the activity takes place, e.g.,area, surface type (pavement, gravel, vegetation,
etc.),and physical characteristics such as site gradients and slope lengths;
• ability of primary and secondary containment(fuel tanks, drum storage, etc.) at product storage and
loading/unloading facilities to prevent and contain spills and leaks;
• proximity of product storage and loading/unloading facilities to waterways or drainage facilities;
• concentration and toxicity of materials which may to be found in the site's stormwater runoff
• contamination of storage facilities/containment with stored materials(e.g., used oil drums or tanks coated with
spilled oil)
Each pollutant source recognized through this process as having the potential to contribute pollutants to stormwater,
must be identified in the SWMP along with the specific stormwater management control (BMPs)that will be
implemented to adequately control the source. Note: the actual evaluation of the potential pollutant sources does
NOT need to be included in the SWMP—just the resultant pollutant sources and their associated BMPs.
•
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Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
Part IC.3 Stormwater Management Plan (SWMP)—
c) Best Management Practices (BMPs)for Stormwater Pollution Prevention- The SWMP shall identify and
describe appropriate BMPs, including, but not limited to, those required by paragraphs 1 through 8 below, that
will be implemented at the facility to reduce the potential of the sources identified in Part I.C.3.b to contribute
pollutants to stormwater discharges. The SWMP shall clearly describe the installation and implementation
specifications for each BMP identified in the SWMP to ensure proper implementation, operation and
maintenance of the BMP.
1) Structural Practices for Erosion and Sediment Control. The SWMP shall clearly describe and locate all
structural practices implemented at the site to minimize erosion and sediment transport. Practices may
include, but are not limited to:straw bales, wattles/sediment control logs, silt fences, earth dikes, drainage
swales, sediment traps, subsurface drains,pipe slope drains, inlet protection, outlet protection, gabions,
and temporary or permanent sediment basins.
2) Non-Structural Practices for Erosion and Sediment Control. The SWMP shall clearly describe and locate,
as applicable, all non-structural practices implemented at the site to minimize erosion and sediment
transport. Description must include interim and permanent stabilization practices, and site-specific
scheduling for implementation of the practices. The SWMP should include practices to ensure that existing
vegetation is preserved where possible. Non-structural practices may include, but are not limited to:
temporary vegetation,permanent vegetation, mulching, geotextiles, sod stabilization, slope roughening,
vegetative buffer strips,protection of trees, and preservation of mature vegetation.
PhasedBMPlmvlementation. The SWMP shall clearly describe the relationship between the phases of
construction, and the implementation and maintenance of both structural and non-structural stormwater
management controls. The SWMP must identify the stormwater management controls to be implemented
during the project phases, which can include, but are not limited to, clearing and grubbing; road
construction; utility and infrastructure installation; vertical construction;final grading; and final
stabilization.
4) Materials Handling and Spill Prevention. The SWMP shall clearly describe and locate all practices
implemented at the site to minimize impacts from procedures or significant materials (see definitions at
Part I.E.) that could contribute pollutants to runoff. Such procedures or significant materials could
include: exposed storage of building materials;paints and solvents;fertilizers or chemicals; waste
material; and equipment maintenance or fueling procedures.
Areas or procedures where potential spills can occur must have spill prevention and response procedures
identified in the SWMP.
5) Dedicated Concrete or Asphalt Batch Plants. The SWMP shall clearly describe and locate all practices
implemented at the site to control stormwater pollution from dedicated concrete batch plants or dedicated
asphalt batch plants covered by this certification.
6) Vehicle Tracking Control. The SWMP shall clearly describe and locate all practices implemented at the
site to control potential sediment discharges from vehicle tracking. Practices must be implemented for all
areas of potential vehicle tracking, and can include: minimizing site access;street sweeping or scraping;
tracking pads;graveled parking areas; requiring that vehicles stay on paved areas on-site; wash racks;
contractor education; and/or sediment control BMPs, etc.
•
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Part I.C.3 Stormwater Management Plan (SWMP)—
7) Waste Management and Disposal. Including Concrete Washout.
i) The SWMP shall clearly describe and locate the practices implemented at the site to control
stormwater pollution from all construction site wastes (liquid and solid), including concrete washout
activities.
ii) The practices used for concrete washout must ensure that these activities do not result in the
contribution of pollutants associated with the washing activity to stormwater runoff.
iii) Part I.D.3.c of the permit authorizes the conditional discharge of concrete washout water to the
ground. The SWMP shall clearly describe and locate the practices to be used that will ensure that no
washout water from concrete washout activities is discharged from the site as surface runoff or to
surface waters.
8) Groundwater and Stormwater Dewatering.
i) The SWMP shall clearly describe and locate the practices implemented at the site to control
stormwater pollution from the dewatering of groundwater or stormwater from excavations, wells, etc.
ii) Part I.D.3.d of the permit authorizes the conditional discharge of construction dewatering to the
ground. For any construction dewatering of groundwater not authorized under a separate CDPS
discharge permit, the SWMP shall clearly describe and locate the practices to be used that will ensure
that no groundwater from construction dewatering is discharged from the site as surface runoff jor to
surface waters.
c. Best Management Practices(BMPs) for Stormwater Pollution Prevention
• i) Selecting and locating appropriate BMPs: When selecting BMPs,consider first those that limit the source
of the pollutant. It is much more efficient, from both a cost and environmental standpoint, to prevent the
pollution in the first place than to clean up polluted stormwater. For example, mulching disturbed ground to
reduce erosion, in most cases, is easier and more effective than trying to capture and treat sediment-laden runoff
before it reaches State waters.
ii) Specific BMPs for Material Handling and Spill Prevention: Where materials can impact stormwater
runoff, existing and planned practices that reduce the potential for pollution must be described. For example,
materials should be stored and handled in covered areas to prevent contact with stormwater, and chemicals
should be stored within berms or other secondary containment devices to prevent leaks and spills from
contacting stormwater runoff. In general, spill prevention and response procedures should include the
following:
• notification procedures to be used in the event of an accident. At the very least,the SWMP Administrator
should be notified. Depending on the nature of the spill and the material involved, the Colorado Department
of Public Health and Environment(24-hour spill reporting line—877-518-5608),downstream water users,
or other agencies may also need to be notified;
• instructions for clean-up procedures, and identification of spill kit location(s);
• provisions for absorbents to be made available for use in fuel areas, and for containers to be available for
used absorbents; and
• procedures for properly washing out concrete truck chutes and other equipment in a manner and location so
that the materials and wash water can not discharge from the site, and never into a storm drain system or
stream.
• Once source reduction BMPs have been evaluated, more costly options, such as mitigation of impacts or
stormwater treatment through detention storage, must be considered as necessary. The selection of BMPs is
subject to the judgment of the individual permittee, based on the conditions at the site. It is important to keep in
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mind that BMPs included in the SWMP and implemented at the site must be adequately designed to provide
control for all potential pollutant sources associated with construction activity to prevent pollution or
degradation of State waters. Therefore, in order to comply with your permit terms and conditions, appropriate
• practices must be implemented in keeping with the pollutant(s) involved and the risk potential at the facility.
Redundant BMP use is highly recommended to eliminate reliance on any one (or two)BMPs, and is often
necessary to provide an adequate treatment train to remove pollutants in runoff.
In addition, the BMPs selected for use must be appropriately designed and implemented, following good
engineering practices. It is best to base BMP design and implementation on professionally accepted references.
Many well-accepted references are available that include guidance on proper BMP selection, design, and
implementation. Some counties, cities,and local agencies have adopted criteria manuals for stormwater BMPs.
Section D.1 of this guidance contains a discussion of additional resources for more in-depth information on
stormwater quality BMPs.
BMP location
A permittee must ensure that BMPs implemented to control stormwater pollution are located prior to the
stormwater discharge to a receiving water or a stormwater collection system. To meet this condition, BMPs may
be implemented at any location that allows for adequate treatment of stormwater pollutants,as long as all of the
following criteria are met:
• All BMPs are located:
o prior to the stormwater leaving the control of the permittee, i.e.,where the permittee is capable of ensuring
the BMPs' proper operation and maintenance(see below section on Ensuring BMPs);
o prior to discharge to a receiving water defined as Waters of the United States(see below section on
Protecting Waters of the US); and
o prior to discharge into a municipal storm sewer or other stormwater collection system not owned by the
permittee(unless specific permission is granted).
0 BMPs are implemented to control all pollutant sources covered by the permit certification (i.e., unmanaged
pollutant sources are not located down slope from the last BMP at a site).
• BMPs are implemented in accordance with the site's SWMP.
Although it is acceptable, and often advisable when used in conjunction with redundant BMPs,to locate structural
BMPs in areas of concentrated flow(e.g., check dams along drainage ditches, detention ponds, etc.), remember
that removing sediment from stormwater is often not as efficient a practice as preventing erosion in the first place,
and that once erosion starts, additional sediment control BMPs will almost always be necessary to prevent the
discharge of sediment from the site. The most efficient construction site BMPs are those that prevent erosion from
occurring.
Ensuring BMPs are under the Control of the Permittee
If a permittee will rely on contracts or agreements with other entities to manage BMPs(e.g., when BMPs will be
located off of the permittee's property and implemented by a second party, such as a site developer), the guidance
found in Part G.2.b of the Stormwater Fact Sheet—Construction(available from the Division's web site at
www.cdphe.state.co.us/wq/PermitsUnit) must be followed to ensure the BMPs are properly addressed in the
SWMP and implemented in the field. A permittee may not rely on a BMP owned or operated by a second party if
the permittee does not have permission to use the BMP, and/or if they do not have any agreements in place to
ensure its adequate operation and maintenance in accordance with the permittee's SWMP.
Protecting Waters of the United States
BMPs must not be located within waterways, including wetlands, that are defined as Waters of the United States,
unless specifically authorized by and in compliance with a separate 404 permit(also referred to as Dredge and Fill
permits) from the U.S. Army Corps of Engineers. Even when BMPs may be authorized in natural waterways,
h BMPs are only intended to control pollutants originating from activities within the waterway, and additional
Ps are still necessary to prevent sediment from the remainder of the site from entering that waterway. Note
that even if a drainage has been modified by a private or municipal entity, it still may be considered Waters of the
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United States. It is the owner and/or operator's responsibility, through consultation with the Army Corps of
Engineers,to confirm the existence of any Waters of the United States at their site. More information on 404
ermitting, including regional office contact information,may be obtained from the Army Corps of Engineers
latory programs' web page at http://www.usace.army.mil/inet/functions/cw/cecwo/reg/, or by calling the
enver Regulatory Office at(303) 979-4120.
iii)Documenting Selected BMPs in the SWMP(including phasing of BMP implementation): The SWMP
must describe the specific stormwater management controls(BMPs)that will be implemented at the site to
adequately control each identified pollutant source(see Section C.4.b, above). Estimated dates for BMP
implementation and maintenance are required,and any existing controls must also be discussed. The plan shall
identify both structural and non-structural control measures that are necessary for erosion and sediment control
at the site. Thoroughly describe how the BMP used at the site will change with the different stages of
construction activity at the site, and make sure that BMPs implemented for dedicated concrete or asphalt batch
plants, if applicable, and vehicle tracking controls, are clearly documented.
BMP description: Level of detail
BMP descriptions provided in the SWMP must contain adequate detail to ensure proper implementation at the site.
The following information must be addressed in the SWMP:
• What BMPs will be implemented?
• When will the BMPs be implemented? Many BMPs will only be implemented during specific phases of the
project. For example, silt fence and detention ponds may be installed prior to grading, while inlet protection
for a newly constructed stormwater collection system will need to be installed upon completion of the inlets.
• Where will the BMPs be implemented? The SWMP must clearly indicate the locations where BMPs will be
implemented. For structural BMPs, this will usually require including the locations on the site map discussed
in Section C.3 above.
How will the BMPs be implemented? The installation and implementation specifications included in the
SWMP must be sufficient to ensure proper implementation, including procedures for operation and
maintenance of the BMP. For structural BMPs, in most cases this must include a technical drawing. For
example, if silt fence will be used at a site, in addition to the timing and location of installation,the SWMP
must provide information such as trenching depth, stake spacing, materials, etc. BMP installation and
implementation criteria must follow good engineering practices. Although it is not necessary to include design
calculations in the SWMP, such as those used to determine pond capacity or slope limitations for silt fence,
this information may be useful to include to assist in proper revisions to the SWMP and site BMPs if and when
necessary,as discussed below.
iv)Non-Stormwater Discharges: Except for emergency fire fighting activities, landscape irrigation return
flow, uncontaminated springs, construction dewatering and concrete wash out water,the Stormwater
Construction Permit only covers discharges composed entirely of stormwater.
.\ Concrete Washout water can NOT be discharged to surface waters or to storm sewer systems without
separate permit coverage. The discharge of Concrete Washout water to the ground, under specific
conditions, may be allowed by the Stormwater Construction Permit when appropriate BMPs are
implemented. Additional information on this subject is available in the Stormwater Fact Sheet—
Construction, available from the Division's web site at www.cdphe.state.co.us/wq/PermitsUnit.
Construction Dewatering water can NOT be discharged to surface waters or to storm sewer systems
without separate permit coverage. The discharge of Construction Dewatering water to the ground, under
specific conditions, may be allowed by the Stormwater Construction Permit when appropriate BMPs are
implemented. Additional information on this subject is available in the Stormwater Fact Sheet—
Construction, available from the Division's web site at www.cdphe.state.co.us/wq/PermitsUnit.
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Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
Aside from the exceptions noted above, non-stormwater discharges must be addressed in a separate permit
issued for that discharge. Contact the Division or visit our web page at www.cdphe.state.co.us/wq/PermitsUnit
for guidance and applications.
• v) Stormwater Dewatering: The discharge of pumped stormwater, only,from excavations, ponds,
depressions, etc., to surface waters, or to a municipal separate storm-sewer system(MS4) is allowed by the
Stormwater Construction Permit, as long as the dewatering activity and associated BMPs are identified in the
SWMP (including location of the activity), and BMPs are implemented in accordance with the SWMP.
Note: Pumping stormwater does not by itself render the pumped water a process water,provided that the pump
does not contribute additional pollutants to the discharge. If,however, a sheen is visible on the water leaving
the pump, a separate discharge permit is required.
d.Revising BMPs and the SWMP: At nearly every site,the implemented BMPs will have to be modified to adapt
to changing site conditions, or to ensure that potential pollutants are consistently and properly managed. The
pollutant sources and management practices at a site must be reviewed on an ongoing basis(and specifically during
the required inspections listed in Part I.D.6 of the Stormwater Construction Permit and discussed below). When
BMPs or other site conditions change,the SWMP must be modified to accurately reflect the actual field
conditions. Examples include, but are not limited to,removal of BMPs, identification of new potential pollutant
sources,addition of BMPs, modification of BMP installation and implementation criteria or maintenance
procedures, and changes in items included in the site map and/or description. SWMP revisions must be made prior
to changes in site conditions except for Responsive SWMP Changes, as follows:
— SWMP revisions must be made immediately after changes are made in the field to address BMP
installation and/or implementation issues; or
— SWMP revisions must be made as soon as practicable, but in no case more than 72 hours after
• change(s) in BMP installation and/or implementation occur at the site that require development of
materials to modify the SWMP(e.g., design of retention pond capacity)
The SWMP should be viewed as a"living document"that is continuously being reviewed and modified as part of
the overall process of assessing and managing stormwater quality issues at the site. The following illustration
summarizes the process of evaluating, selecting,documenting, implementing, and revising BMPs.
Evaluate Pollutant Sources
Implement BMPs Select BMPs
Document BMPs
•
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C.5 SWMP CONTENTS—Final Stabilization and Long-term Stormwater Management
Part I.C.4 Stormwater Management Plan (SWMP)—Contents: Final Stabilization and Lone-term Stormwater
ana ement
The SWMP shall clearly describe the practices used to achieve final stabilization of all disturbed areas at the
site, and any planned practices to control pollutants in stormwater discharges that will occur after construction
operations have been completed at the site.
b) Final stabilization practices for obtaining a vegetative cover should include, as appropriate:seed mix selection
and application methods;soil preparation and amendments;soil stabilization practices (e.g., crimped straw,
hydro mulch or rolled erosion control products);and appropriate sediment control BMPs as needed until final
stabilization is achieved; etc.
c) Final stabilization is reached when all ground surface disturbing activities at the site have been completed, and
uniform vegetative cover has been established with an individual plant density of at least 70 percent of pre-
disturbance levels, or equivalent permanent,physical erosion reduction methods have been employed.
The Division may, after consultation with the permittee and upon good cause, amend the final stabilization criteria in
this section for specific operations.
Typically,the stormwater discharges associated with construction activity are eliminated when the site is finally
stabilized. As soon as practicable after construction activities have been completed in a disturbed area, permanent
stabilization should be started to prevent further erosion of soil from that area. All disturbed areas(except those
portions covered by pavement or a structure)must be finally stabilized once all construction activities are completed in
order to inactivate the permit coverage. Sediment that collects within the site's drainage system and permanent water
quality or quantity controls is also considered unstabilized soil,and must be removed prior to the site being considered
Afistiry;
abilized.
MP must include a description of what measures will be taken to finally stabilize the site. The method of
stabilization must be provided for all areas that will remain pervious(i.e.,vegetated or landscaped instead of paved,
built on,or otherwise structurally stabilized). Questions that may need to be addressed include: What type of cover
will be used? What are the specific seed mixtures and application rates? Are additional BMPs needed to prevent
erosion as the vegetation becomes established? Will the soil need to be amended? Will special methods be employed
on any steep slopes or areas of concentrated flow?
Inactivation of permit coverage
Coverage under the Stormwater Construction Permit may be inactivated by the permittee when the site has
attained final stabilization, all temporary erosion and sediment control measures have been removed, and all
components of the SWMP are complete.
Any planned stormwater management controls to prevent or control pollution of stormwater after construction is
completed must be addressed here. They typically include retention or detention ponds, infiltration measures,
vegetative swales,and natural depressions.
New developments, buildings, etc.,will often incorporate elements of permanent stormwater quality control into their
design. The SWMP must be prepared consistent with these structural and nonstructural controls. Where possible,
permanent stormwater quality controls can be constructed at the initial stages of construction, or modified at the end of
construction. This can increase the efficiency of the controls by using them during both the building and operational
phases of the project. When a permanent structural control is initially used as a construction BMP, the SWMP must
coin the necessary information discussed in the guidance for documenting BMPs, Section C.4 above.
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v- _
Use of Permanent Detention Ponds as BMPs during Construction
Permanent detention ponds are allowed to be used as a temporary construction BMP, if: a)the pond is clearly
qtfrignated as a construction BMP in the SWMP; b)detention pond inspection and maintenance are described as
quired in Part I.B.2,Part I.C.3, and Parts I.D.6, 7,and 8 of the Stormwater Construction Permit; and c)the pond
is designed and implemented for use as a BMP during construction in accordance with good engineering,
hydrologic and pollution control practices. In addition, stormwater discharges from the pond must not cause or
threaten to cause pollution or degradation of State waters. When a permanent detention pond is used in this
manner, redundant upgradient erosion and sediment control BMPs are still necessary in almost all cases to comply
with the permit requirements to select and design BMPs to prevent pollution or degradation of State waters.
The design and implementation of the pond may differ from what will exist upon completion of the project when
the BMP becomes a permanent water quality feature. In this case,the description of the BMP included in the
SWMP must address these differences. For example, if the outfall will be modified during construction to provide
additional filtering or settling of sediment(which may or may not be necessary, depending on the existence of
upstream BMPs, sediment loading to the pond, final outlet design,etc.), those modifications must be included in
the SWMP. If additional temporary stabilization of the pond(e.g.,at points of concentrated flow into or through
the pond, unstable slopes,etc.) is needed to prevent erosion and transport of sediment from the pond during
construction,this must also be addressed.
Prior to inactivation of the permit,the pond must be stabilized in accordance with the permit requirements and
sediment removed from the site's drainage system. Although not related to compliance with the construction
stormwater permit,the pond may need to be inspected and modified following construction in order to meet local
permanent BMP design criteria.
C.6 SWMP CONTENTS—Inspection and Maintenance Procedures
rt I.C.5. Stormwater Management Plan (SWMP)—Contents: -Inspection and Maintenance
art I.D.6 of the permit includes requirements for site inspections. Part I.D.7 of the permit includes requirements for
BMP maintenance. The SWMP shall clearly describe the inspection and maintenance procedures implemented at the
site to maintain all erosion and sediment control practices and other protective practices identified in the SWMP, in
good and effective operating condition.
a. Inspection Schedules: The minimum inspection schedule described in Part I.C.6.a of the Stormwater
Construction Permit requires that a thorough inspection of the stormwater management system be performed and
documented at least every 14 days, and within 24 hours of any precipitation or snowmelt event that causes surface
erosion (i.e., that results in stormwater running across the ground). If more frequent inspections are required to
ensure that BMPs are properly maintained and operated,the inspection schedule must be modified to meet this need.
Exceptions to the minimum inspection schedule are also provided. Any use of an exception is temporary, and does
not eliminate the requirement to perform routine maintenance due to the effects of a storm event or other conditions
that may impact BMP performance, including maintaining vehicle tracking controls and removing sediment from
impervious areas.
Additionally,this part of the SWMP must also include maintenance procedures for the BMPs, as discussed below.
You will need to set up a schedule appropriate to the activity and the BMP. Preventive maintenance should be
coupled with periodic inspections.
b.Inspection Procedures: The inspection must include observation of:
• the construction site perimeter and discharge points(including discharges into a storm sewer system);
•• all disturbed areas;
• areas used for material/waste storage that are exposed to precipitation;
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• other areas determined to have a significant potential for Stormwater pollution, such as demolition areas or
concrete washout locations,or locations where vehicles enter or leave the site;
• erosion and sediment control measures identified in the SWMP; and
• • any other structural BMPs that may require maintenance, such as secondary containment around fuel tanks,
or the condition of spill response kits.
The inspection must determine if there is evidence of, or the potential for, pollutants entering the drainage system.
BMPs should be reviewed to determine if they still meet the design and operational criteria in the SWMP, and if
they continue to adequately control pollutants at the site. Any BMPs not operating in accordance with the SWMP
must be addressed as soon as possible, immediately in most cases, to minimize the discharge of pollutants, and the
SWMP must be updated as described in Section C.4.e, above. Inspections must be documented as discussed in the
Record Keeping section, below.
c.BMP Maintenance/Replacement and Failed BMPs: The Stormwater Construction Permit requires that all
erosion and sediment control practices and other protective measures identified in the SWMP be maintained in
effective operating condition and in accordance with good engineering, hydrologic and pollution control
practices. Therefore, site inspection procedures must address maintenance of BMPs that are found to no longer
function as needed and designed,as well as preventive maintenance to proactively ensure continued operation (e.g.,
removing collected sediment outside the acceptable tolerances of the BMP).
A preventive maintenance program should prevent BMP breakdowns and failures by proactively maintaining or
replacing BMPs and equipment. Site inspections should uncover any conditions, such as deteriorating silt fence or
water collected in fuel tank secondary containment, which could result in the discharge of pollutants to storm sewers
and surface waters. For example, sediment that has been collected by sediment controls, such as silt fence and inlet
protection, should be removed on a regular basis,to prevent failure of BMPs, and remove the potential of that
sediment from being discharged from the site if the BMP did fail. Removed sediment must be moved to an
ppropriate location where it will not become an additional pollutant source, and should never be placed in ditches
streams. Maintenance activities to correct problems noted during inspections must be documented as discussed in
e Record Keeping section,below.
The inspection process must also include procedures to ensure that, when needed, BMPs are replaced or new BMPs
added to adequately manage the pollutant sources at the site. This procedure is part of the ongoing process of
revising the BMPs and the SWMP as discussed Section C.4, above, and any changes to BMPs must be recorded in
the SWMP. The SWMP must be modified as appropriate as soon as practicable after such inspections.
BMPs that have failed, or have the potential to fail without maintenance or modifications, must be addressed as soon
as possible, immediately in most cases,to prevent the discharge of pollutants.
d.Record Keeping and Documenting Inspections: Keeping accurate and complete records serves several
functions. First,keeping records of spills, leaks, inspections,etc. is a requirement of the Stormwater Construction
Permit;therefore,enforcement action, including fines, could result if records are not adequate. Second, by keeping
accurate and detailed records, you will have documentation of events which could prove invaluable should
complications arise concerning the permit, lawsuits, etc.
The permittee must document inspection results and maintain a record of the results for a period of 3 years
following expiration or inactivation of permit coverage. These records must be made available to the Division or
EPA upon request. The following items must be documented as part of the site inspections:
i) The inspection date;
ii) Name(s) and title(s) of personnel making the inspection;
iii) Location(s)of discharges of sediment or other pollutants from the site;
• Location(s) of BMPs that need to be maintained;
Location(s)of BMPs that failed to operate as designed or proved inadequate for a particular location;
vi) Location(s)where additional BMPs are needed that were not in place at the time of inspection;
vii) Deviations from the minimum inspection schedule as provided in Section C.6.a above;
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viii) Description of corrective action for items iii, iv, v, and vi,above, dates corrective action(s)taken, and
measures taken to prevent future violations, including requisite changes to the SWMP, as necessary;and
ix)
After adequate corrective action(s)has been taken, or where a report does not identify any incidents requiring
corrective action,the report shall contain a signed statement indicating the site is in compliance with the
permit to the best of the signer's knowledge and belief
In addition to inspection records, the permittee may opt to keep a log book for use in tracking other items related to
the SWMP such as those listed below. Additional information such as dated photographs, field notebooks,drawings
and maps, and the items below, etc. can also be included where appropriate.
• BMP operation and maintenance
• stormwater contamination
• contacts with suppliers
• notes on the need for and performance of preventive maintenance and other repairs
• implementation of specific items in the SWMP
• training events(given or attended)
• events involving materials handling and storage
• contacts with regulatory agencies and personnel
• notes of employee activities, contact,notifications, etc.
Records of spills, leaks, or overflows that result in the discharge of pollutants must be documented and maintained.
You may also want to record other spills that are responded to,even if they do not result in a discharge of pollutants.
Information that should be recorded for all occurrences includes the time and date, weather conditions, reasons for
the spill, etc. Some spills may need to be reported to the Division immediately. Specifically, a release of any
chemical,oil,petroleum product, sewage, etc.,which may enter waters of the State of Colorado(which include
surface water, ground water and dry gullies or storm sewers leading to surface water)must be reported. More
�uidance is available on the web at www.cdphe.state.co.us/hm/spillsandreleases.htm. The Division's toll-free 24-
ur number for environmental hazards and chemical spills and releases is 1-877-518-5608.
D. ADDITIONAL SWMP AND BMP RESOURCES
There are a multitude of resources available to the construction industry to assist in complying with the requirements of
the Stormwater Construction Permit. The following suggested list of resources can provide valuable tools to assist you
in developing and implementing your SWMP as effectively and efficiently as possible. However,the guidance found in
the resources listed below in no way replaces the requirements of the Stormwater Construction Permit, as described in
Sections A through C, above. Therefore,when using the following resources, especially in the case of example plans
and maps, it is essential that you ensure that all of the requirements included in this guidance document and the
Stormwater Construction Permit are being met.
Many of the resources below require access to the internet. If you are unable to obtain any resources you need due to a
lack of access to the internet, please contact the Division at(303) 692-3517 and we can try to assist you in obtaining the
information you need.
D.1. RESOURCES—BMP Design and Implementation
a. BMP Design Criteria Manuals:
Be sure to check with the local city or county to determine if they require that specific design criteria be met. The
following are some highly respected criteria manuals that can be used in designing and implementing BMPs for
your site.
•
Appendix A-Page 17 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
• Urban Drainage and Flood Control District
Urban Storm Drainage Criteria Manual Volume 3—Best Management Practices
o This criteria manual is commonly used by cities and counties in the Denver metropolitan area. The
• manual includes discussion of stormwater quality management and BMPs for many activities, including
construction.
This manual is a highly respected across the country and a great resource for professionally accepted
design criteria for construction BMPs.
• Available free from the"download"section of the Urban Drainage and Flood Control District
web page:
http://www.udfcd.org/
• Douglas County
Grading,Erosion,and Sediment Control(GESC)Manual
o The criteria manual for compliance with Douglas County's GESC permitting program for stormwater
quality. Includes an excellent discussion of effective stormwater management strategies,design criteria,
and several very useful sample site maps.
• Available for download free from the Douglas County Public Works web page:
http://www.douglas.co.us/publicworks/engineering/GESC.html
• Also available in print or CD-ROM from the Engineering Division office:
Douglas County Public Works Department- Engineering Division
100 Third Street
Castle Rock,CO 80104
Phone: 303-660-7490
b. General BMP Selection and Design Guidance
• Colorado Department of Transportation
• Erosion Control and Stormwater Quality Guide
o Guidance on BMP selection and design applicable specifically to highway development projects,but
also useful as general guidance.
• Available online from CDOT's MS4 Program web page at:
http://www.dot.state.co.us/environmental/envWaterOual/wqms4.asp
• EPA Menu of BMPs
Construction Site Storm Water Runoff Control
o EPA guidance for cities and counties who are required to develop programs to regulate construction
activities in their jurisdiction. The BMP fact sheets provide a good discussion of various structural and
nonstructural BMPs.
• Available online at: http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm
• International Stormwater Best Management Practices(BMP)Database
o Database of monitoring results showing effectiveness of structural and non-structural BMPs.Currently,
the database and web site do not include much analysis of the data;this will be added in the future. Data
contributions are being solicited on an ongoing basis.
• Available online at:
http://www.bmpdatabase.org
c. Special Applications
• Burn Areas:
• U.S. Department of Agriculture, Forest Service, 2006. Burned Area Emergency Response Treatments Catalog.
0625 1801-SDTDC.
• Available online at: http://www.fs.fed.us/eng/pubs/pdf/BAERCAT/lo_res/TOContents.pdf
Appendix A-Page 18 of 19 Revised 7/07
Water Quality Control Division—Stormwater Program www.cdphe.state.co.us/wq/permitsunit
• Soil Bioengineering:
U.S. Department of Agriculture, Forest Service, 2000. Soil Bioengineering An Alternative for Roadside
• Management. 0077 1801-SDTDC.
• Available online at:
http://ttap.colostate.edu/Library/MISC/USDA%200077%201801%20SDTDC.pdf
Franti,Thomas G. 2006. Bioengineering for Hillslope, Streambank and Lakeshore Erosion Control. University
of Nebraska—Lincoln Extension.
• Available online at: http://www.ianrpubs.unl.edu/epublic/live/g1307/build/g1307.pdf
D.2.RESOURCES—Example Management Plans
• Construction Industry Compliance Assistance Center- Stormwater Pollution Prevention Plans
o A website with examples of actual stormwater plans prepared for a range of construction projects located in
various states. "The purpose of presenting these documents is to demonstrate various approaches to SWPPP
development. Please note that the examples presented here should not be excerpted or used as templates in
the preparation of a SWPPP, since each SWPPP must be designed to handle the specific needs of a particular
construction site." (Note that Colorado's plan is referred to as a `SWMP' instead of`SWPPP'.) Not all of
the example plans will meet the requirements of the Colorado General Permit.Therefore, it is essential that
this SWMP/S WPPP guidance document be used to ensure your completed plan contains all of the required
elements and is appropriate for your site.
• Available online at: http://www.cicacenter.org/swppp.html
D.3.RESOURCES—Training
• Rocky Mountain Education Center(Located at Red Rocks Community College, Lakewood)-
• Stormwater Management and Erosion Control Course
o One-day course,with an optional additional half-day in the field, on the principles and practices of
erosion and sediment control. Recommended for municipal erosion control inspectors and those
practicing erosion control in the field. This course is required for the CDOT certified erosion control
supervisor certification. Course is given at Red Rocks Community College in Lakewood. Course CETC
#150.
Stormwater Compliance Inspector Course
o Two-day course(including half-day in the field)on preparing for and conducting a comprehensive
construction site inspection. Recommended for municipal erosion control inspectors, construction site
managers,and those practicing erosion control in the field. Prerequisite: Stormwater Management and
Erosion Control Course(see above). Course is given at Red Rocks Community College in Lakewood.
Course CETC#151.
• Contact the Rocky Mountain Education Center at(800)933-8394
• Schedule of classes available online at: http://www.rrcc.edu/rmec/cetc.html
• Keep it Clean Partnership(Boulder)
Erosion Control Training and Certification
o The Keep it Clean Partnership provides a low-cost,eight-hour erosion control training and recertification
program available for both public and private inspectors and contractors.
• Contact the Keep it Clean Partnership at 303-441-1439
• http://bcn.boulder.co.us/basin/kicp//kicp construction.htm
•
Appendix A-Page 19 of 19 Revised 7/07
OFFICE OF THE STATE ENGINEER
DIVISION OF WATER RESOURCES
1313 Shaman Street,Room 818
Denver, Colorado 80203
• DO NOT WRI E ABOVE T i LINE
NAME OF DAIS .•WATER DIV . .O
DATE APP1IC COMPIETWe YES NO DATE RETURNED:. .. •
APPLICATION FOR REVIEW OF PLANS AND SPECIFICATIONS
FOR THE CONSTRUCTION OR ENLARGEMENT OF A DAM AND RESERVOIR
(File in duplicate,original signatures required on both. PLEASE PRINT OR TYPE APPLICATION)
CHECK ONE New Dam ,Enlargement*_
(SEE C.R.S. 37-87-101,et al, and Regulations for Dam Safety and Dam Construction)
I, ,owner, hereby accept
(Name of Owner)
and approve the enclosed plans and specifications for submittal to the State Engineer in accordance with¢37-87-105, C.R.S.
(Signature of Owner/Agent) (Date)
Address:
Street or P.O. Box City, State, Zip Code
Phone Number( )
•Owner Code(CHECK ONE): Corps of Eng.(C)_, Other Federal(G)_, District(D) , County(K)_,
Municipal(M)_, Private(P)_, State(S)_.
NAME OF DAM(on file with the state engineer): DAMID:
Also Known As:
RESERVOIR NAME:
STATE ENGINEER'S DRAWING FILE NUMBER(on file with state engineer, i.e., C-NNNNX):
Location: PM,Twnsbp. ,Rng. ,Sec. _, Lat. _,Long. _, County
Stream Name: ,Tributary To:
GENERAL INFORMATION
Dam and Reservoir Use:
(Augmentation,Diversion, Domestic, Erosion Control, Evaporation,Flood Control, Fire Control,Fish,Hydroelectric, Industrial,
Irrigation, Mining,Municipal,Pollution Control,Recreation, Stockwater, Settling Ponds, Sewage, Tailings,Waste Disposal)
Consulting Engineer: - Company:
Address:
Street or P.O. Box City, State, ZIP Code
Phone Number: ( ) Colorado P.E. Registration Number
• (PAGE 1 OF 3)
CONSTRUCTION OR ENLARGEMENT FORM
Owner's Responsible Person:
•Address:
Street or P.O. Box City, State, ZIP Code
Phone Number: ( ) (primary) ( ) (secondary)
DESCRIPTION OF DAM AND RESERVOIR
Tvoe of Dam- (Check Type)
Concrete Gravity Arch
Earthgl Zoned Homogeneous
Rockfill Zoned Impervious Membrane
Masonry Other
Hazard Classification: _I, II, III, IV
STRUCTURAL DATA
Dam (Dimensions to nearest tenth of foot, volume to nearest acre-foot or cubic-yard, areas to nearest acre)
Jurisdiction Height ft. (Natural surface of ground to bottom of emergency spillway at longitudinal centerline)
Embankment Height . ft. (jurisdictional height plus emergency spillway freeboard)
Structural Height . ft. (bottom of cutoff trench to crest of dam at centerline)
Crest Length ft.; Crest Width ft.; Crest Elev.
Embankment Volume C.Y.
• Maximum Impoundment Capacity •
Acre-Feet (to crest of dam)
Normal Reservoir Capacity Acre-Feet (at high waterline)
Reservoir Surface Area Acres (at high water line)
U/S Slope . :1, D/S Slope . :1
Upstream(U)/Downstream(D). Facing Material (Place U or D as appropriate)
Concrete Darn , Concrete Facing , Clay_, Gabions , Gravel
Handplaced riprap , Masonry Dam_, Natural
Planted ,riprap with bedding_, riprap with no bedding ,Rock Zone
Soil Cement , Steel , Wood_Other? (Describe)
Outlet
Outlet Diameter: Inches/Feet Type:
Comments:
• Maximum Discharge Capacity: cfs (Reservoir at high water line)
(PAGE 2 OF 3)
CONSTRUCTION OR ENLARGEMENT FORM
Spillway
• 1. Type: ;(i.e., Emergency; Principal)
Material: ;(i.e., Natural, riprap, Concrete, CMP, RCP, etc.,)
Width(Diam): ft., Freeboard: ft., Capacity: ,cfs
2. Type: ;(i.e., Emergency, Principal)
Material: ;(i.e., Natural, riprap, Concrete, Cmp, RCP, etc.,)
Width(Diem): ft., Freeboard: ft., Capacity: ,cfs
Total Spillway Capacity: cfs, (Crest of the dam)
HYDROLOGIC DATA(Design Storm)
Drainage Area: Acres, or Sq. Miles
Inflow Design Flood: ,(i.e., 100-year %PMP, etc) Duration Hrs
Type: ,(i.e., Thunderstorm, General, Snowmelt, Combination)Data Source Ref.
Peak Discharge cfs; Volume A.,F., Basin lag time(Tc): Hrs.
Method of determination: (Describe variable sand indicate value, i.e., USER lag: Lz, Lcz, Knz, 5z, etc):
•Inflow Design Flood routes though reservoir with ft. residual freeboard.
• (PAGE 3 OF 3)
ill
U.S.DEPARTMENT OF HOMELAND SECURITY-FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B.NO.1660-0015
PROPERTY INFORMATION FORM Expires December 31,2010
PAPERWORK BURDEN DISCLOSURE NOTICE
Public reporting burden for this form is estimated to average 1.63 hours per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources,gathering and maintaining the needed data,and completing,reviewing, and submitting the form. You are not required
to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding
the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of
Homeland Security, Federal Emergency Management Agency, 500 C Street, SW,Washington DC 20472, Paperwork Reduction Project (1660-0015).
Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed
survey to the above address.
This form may be completed by the property owner,property owner's agent,licensed land surveyor,or registered professional engineer to support a
request for a Letter of Map Amendment(LOMA),Conditional Letter of Map Amendment(CLOMA),Letter of Map Revision Based on Fill(LOMR-F),or
Conditional Letter of Map Revision Based on Fill(CLOMR-F)for existing or proposed,single or multiple lots/structures. In order to process your request,
all information on this form must be completed in its entirety. Incomplete submissions may result in processing delays. Please check the item below
that describes your request: -
n L• OMA A letter from DHS-FEMA stating that an existing structure or parcel of land that has not been elevated
by fill(natural grade)would not be inundated by the base flood.
n C• LOMA A letter from DI-IS-FEMA stating that a proposed structure that is not to be elevated by fill(natural
grade)would not be inundated by the base flood if built as proposed.
n L• OMR-F A letter from DHS-FEMA stating that an existing structure or parcel of land that has been elevated by
fill would not be inundated by the base flood.
n C• LOMR-F A letter from DHS-FEMA stating that a parcel of land or proposed structure that will be elevated by
fill would not be inundated by the base flood if fill is placed on the parcel as proposed or the structure
is built as proposed.
Fill is defined as material from any source(including the subject property)placed that raises the ground to or above the Base Flood Elevation(BFE).
The common construction practice of removing unsuitable existing material(topsoil)and backfilling with select structural material is not considered the
placement of fill if the practice does not alter the existing(natural grade)elevation,which is at or above the BFE. Fill that is placed before the date of
the first National Flood Insurance Program(NFIP)map showing the area in a Special Flood Hazard Area(SFHA)is considered natural grade.
s fill been placed on your property to raise
round that was previously below the BFE? n Yes n No If yes,when was fill placed? I
month/year
Will fill be placed on your property to raise
ground that is below the BFE? n Yes n No If yes,when will fill be placed? 1
month/year
1. Street Address of the Property(if request is for multiple structures,please attach additional sheet):
2. Legal description of Property(Lot,Block,Subdivision)(complete description as it appears in the Deed is not necessary):
3. Are you requesting that the SFHA designation be removed from(check one):
n the entire legally recorded property?
n a portion of land within the bounds of the property?(A certified metes and bounds description and map of the area to be removed,
certified by a licensed land surveyor or registered professional engineer,are required.For the preferred format of metes and
bounds descriptions,please refer to the MT-1 Form 1 Instructions.)
nstructures on the property? What are the dates of construction?
4. Is this request for a(check one):
nsingle structure
n single lot
nmultiple structures(How many structures are involved in your request?List the number: )
nmultiple lots(How many lots are involved in your request?List the number: )
•
DHS-FEMA Form 81-87,DEC 07 Property Information Form MT-1 Form 1 Page 1 of 2
In addition to this form(MT-1 Form 1),ALL requests must include the following:
• • Copy of the effective FIRM panel and/or Flood Boundary and Floodway Map(FBFM)(if applicable)on which the property location has been
accurately plotted(property inadvertently located in the NFIP regulatory floodway will require Section B of MT-1 Form 3)
• Copy of the Plat Map for the property(with recordation data and stamp of the Recorder's Office)
OR
• Copy of the property Deed(with recordation data and stamp of the Recorder's Office),accompanied by a tax assessors map or other certified
map showing the surveyed location of the property relative to local streets and watercourses
• Form 2—Elevation Form. If the request is to remove the structure,and an Elevation Certificate has already been completed for this property,
it may be submitted in lieu of Form 2. If the request is to remove the entire legally recorded property,or a portion thereof,the lowest lot
elevation must be provided on Form 2.
Please include a map scale and North arrow on all maps submitted.
For LOMR-Fs and CLOMR-Fs,the following must be submitted in addition to the items listed above:
• Form 3—Community Acknowledgment Form
Processing Fee(see instructions for appropriate mailing address;or,visit http:l/www.fema.govlfhm/frm_fees.shtm for the most current fee schedule)
Revised fee schedules are published periodically,but no more than once annually,as noted in the Federal Register. Please note: single/multiple
lot(s)/structure(s)LOMAs are fee exempt. The current review and processing fees are listed below:
Check the fee that applies to your request:
n $• 325(single lot/structure LOMR-F following a CLOMR-F)
[1 $• 425(single lot/structure LOMR-F)
• 1 $500(single lot/structure CLOMA or CLOMR-F)
n $• 700(multiple lot/structure LOMR-F following a CLOMR-F,or multiple lot/structure CLOMA)
n $800(multiple lot/structure LOMR-F or CLOMR-F)
Please submit the Payment Information Form for remittance of applicable fees. Please make your check or money order payable to:National Flood
Insurance Program.
All documents submitted in support of this request are correct to the best of my knowledge. I understand that any false statement may be punishable by
fine or imprisonment under Title 18 of the United States Code,Section 1001.
Applicants Name: Company:
Please Print or Type
Mailing Address: Daytime Telephone No.:
E-Mail Address: Fax No.:
(optional)
Date Signature of Applicant(required)
If you have any questions conceming DHS-FEMA policy,or the NFIP in general,please contact the FEMA Map Assistance Center toll free at 1-877-
FEMA MAP(1-877-336-2627),or visit the Flood Hazard Mapping website at http://www.fema.gov/fhm/.
•
DHS-FEMA Form 81-87,DEC 07 Property Information Form MT-1 Form 1 Page 2 of 2
U.S.DEPARTMENT OF HOMELAND SECURITY-FEDERAL EMERGENCY MANAGEMENT AGENCY O..MB.NO.1660-0015
• ELEVATION FORM Expires December 31,2010
• PAPERWORK BURDEN DISCLOSURE NOTICE
Public reporting burden for this form is estimated to average 1.25 hours per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources,gathering and maintaining the needed data,and completing,reviewing,and submitting the form. You are not required
to respond to this collection of information unless a valid OMB control number appears in the upper right comer of this form. Send comments regarding
the accuracy of the burden estimate and any suggestions for reducing this burden to:Information Collections Management,U.S.Department of
Homeland Security,Federal Emergency Management Agency,500 C Street,SW,Washington DC 20472,Paperwork Reduction Project(1660-0015).
Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed
survey to the above address.
This form must be completed for requests and must be completed and signed by a registered professional engineer or licensed land surveyor. A DHS-
FEMA National Flood Insurance Program(NFIP)Elevation Certificate may be submitted in lieu of this form for single structure requests.
For requests to remove a structure on natural grade OR on engineered fill from the Special Flood Hazard Area(SFHA),submit the lowest adjacent
grade(the lowest ground touching the structure),including an attached deck or garage.For requests to remove an entire parcel of land from the SFHA,
provide the lowest lot elevation;or,if the request involves an area described by metes and bounds,provide the lowest elevation within the metes and
bounds description.In order to process your request,all information on this form must be completed in its entirety. Incomplete submissions may result in
processing delays.
1. NFIP Community Number: Property Name or Address:
2. Are the elevations listed below based on n existing or 1-1 I proposed conditions? (Check one)
3. What is the elevation datum?I 1 NGVD 29 n NAVD 88 Fl Other(explain) If any of the elevations listed below were
computed using a datum different than the datum used for the effective Flood Insurance Rate Map(FIRM)(e.g.,NGVD 29 or NAVD 88),what was
the conversion factor?
Local Elevation+1-ft=FIRM Datum •
4. Please provide the Latitude and Longitude of the most upstream edge of the structure(in decimal degrees):
Indicate Datum: ❑ NAD83 0 NAD27 . Lat. . Long.
Please provide the Latitude and Longitude of the most upstream edge of the property(in decimal degrees):
Indicate Datum: 0 NAD83 ❑ NAD27 Lat. Long.
allFor the existing or�pr'oposed structures listed below,what are the types of construction? (check all that apply)
ncrawl space I l slab on grade n basement/enclosure n other(explain)
6. Has DHS-FEMA identified this area as subject to land subsidence or uplift?(see instructions) ❑ Yes Fl No
If yes,what is the date of the current releveling? / (month/year)
Lowest
Block Lowest Lot Adjacent Base Flood
Lot Number Number Elevation' Grade To BFE Source For OHS-FEMA Use Only
S Elevation
tructure
This certification is to be signed and sealed by a licensed land surveyor, registered professional engineer, or architect authorized by law to certify
elevation information. All documents submitted in support of this request are correct to the best of my knowledge. I understand that any false
statement may be punishable by fine or imprisonment under Title 18 of the United States Code,Section 1001.
Certifiers Name: License No.: Expiration Date:
Company Name: Telephone No.: Fax No.:
Signature: Date:
For requests involving a portion of property,include the lowest ground elevation within the metes and bounds description.
ase note:If the Lowest Adjacent Grade to Structure is the only elevation provided,a determination will be issued
Tor the structure only. Seal (optional)
DHS-FEMA Form 81-87A,DEC 07 Elevation Form MT-1 Form 2 Page 1 of 2
Continued from Page 1.
Block Lowest Lot Lowest Base Flood
of Number Number Elevation Adjacent Grade Elevation BFE Source For OHS-FEMA Use Only
To Structure
•
This certification is to be signed and sealed by a licensed land surveyor, registered professional engineer, or architect authorized by law to certify
elevation information. All documents submitted in support of this request are correct to the best of my knowledge. I understand that any false
statement may be punishable by fine or imprisonment under Title 18 of the United States Code,Section 1001.
Certifiers Name: License No.: Expiration Date:
Company Name: Telephone No.: Fax No.:
Signature: Date:
Seal (optional)
•
DHS-FEMA Form 81-87A,DEC 07 Elevation Form MT-1 Form 2 Page 2 of 2
U.S.DEPARTMENT OF HOMELAND SECURITY-FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B.NO.1660-0015
COMMUNITY ACKNOWLEDGMENT FORM Expires'December 31,2010
• PAPERWORK BURDEN DISCLOSURE NOTICE
ublic reporting burden for this form is estimated to average 1.38 hours per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources,gathering and maintaining the needed data,and completing, reviewing, and submitting the form. You are not required
to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding
the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of
Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project(1660-0015).
Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed
survey to the above address.
This form must be completed for requests involving the existing or proposed placement of fill (complete Section A) OR to provide acknowledgment of
this request to remove a property from the SFHA which was previously located within the regulatory floodway(complete Section B).
This form must be completed and signed by the official responsible for floodplain management in the community. The six digit NFIP community
number and the subject property address must appear In the spaces provided below. Incomplete submissions may result in processing delays.
Community Number. Property Name or Address:
A. REQUESTS INVOLVING THE PLACEMENT OF FILL
As the community official responsible for floodplain management,I hereby acknowledge that we have received and reviewed this Letter of Map Revision
Based on Fill(LOMR-F)or Conditional LOMR-F request. Based upon the community's review,we find the completed or proposed project meets or is
designed to meet all of the community floodplain management requirements,including the requirement that no fill be placed in the regulatory floodway,
and that all necessary Federal,State,and local permits have been,or in the case of a Conditional LOMR-F,will be obtained. In addition,we have
determined that the land and any existing or proposed structures to be removed from the SFHA are or will be reasonably safe from flooding as defined in
44CFR 65.2(c),and that we have available upon request by DHS-FEMA,all analyses and documentation used to make this determination. For LOMR-F
requests,we understand that this request is being forwarded to DHS-FEMA for a possible map revision. For LOMR-F or Conditional LOMR-F requests
that have the potential to impact an endangered species,documentation will be submitted to show that we have complied with Sections 9 and 10 of the
Endangered Species Act(ESA). Section 9 of the ESA prohibits anyone from"taking"or harming an endangered species. If an action might harm an
endangered species,a permit is required from U.S.Fish and Wildlife Service or National Marine Fisheries Service under Section 10 of the ESA. For
actions authorized,funded,or being carried out by Federal or State agencies,documentation from the agency showing its compliance with Section
7(a)(2)of the ESA will be submitted.
ommunity Comments:
Community Official's Name and Title: (Please Print or Type) Telephone No.:
Community Name: Community Official's Signature: (required) Date:
B. PROPERTY LOCATED WITHIN THE REGULATORY FLOODWAY
As the community official responsible for floodplain management,I hereby acknowledge that we have received and reviewed this request for a LOMA.
We understand that this request is being forwarded to DHS-FEMA to determine if this property has been inadvertently included in the regulatory
floodway. We acknowledge that no fill on this property has been or will be placed within the designated regulatory floodway. We find that the completed
or proposed project meets or is designed to meet all of the community floodplain management requirements.
Community Comments:
Community Official's Name and Title: (Please Print or Type) Telephone No.:
Community Name: Community Official's Signature(required): Date:
•
DHS-FEMA Form 81-878,DEC 07 Community Acknowledgment Form MT-1 Form 3 Page 1 of 1
U.S.DEPARTMENT OF HOMELAND SECURITY-FEDERAL EMERGENCY MANAGEMENT AGENCY O.M..B No.16604016 7/2
OVERVIEW & CONCURRENCE FORM Expires:12/3010
PAPERWORK BURDEN DISCLOSURE NOTICE
Public reporting burden for this form is estimated to average 1 hour per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources,gathering and maintaining the needed data,and completing,reviewing,and submitting the form. You are not required
to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send comments regarding
the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, U.S. Department of
Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction Project (1660-0016).
Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed
survey to the above address.
A. REQUESTED RESPONSE FROM DHS-FEMA
This request is for a(check one):
❑ CLOMR: A letter from DHS-FEMA commenting on whether a proposed project,if built as proposed,would justify a map revision,or
proposed hydrology changes(See 44 CFR Ch.1,Parts 60,65&72).
❑ LOMR: A letter from DHS-FEMA officially revising the current NFIP map to show the changes to floodplains,regulatory floodway or
flood elevations.(See 44 CFR Ch. 1,Parts 60,65&72)
B. OVERVIEW
1. The NFIP map panel(s)affected for all impacted communities is(are):
Community No. Community Name State Map No. Panel No. Effective Date
Ex:480301 City of Katy TX 480301 0005D 02/08/83
480287 Harris County TX 48201C 0220G 09/28/90
•
2. a. Flooding Source:
b.Types of Flooding: ❑Riverine 0 Coastal 0 Shallow Flooding(e.g.,Zones AO and AH)
❑Alluvial fan ❑Lakes ❑Other (Attach Description)
3. Project Name/Identifier:
4. FEMA zone designations affected: (choices: A,AR,AO,A1-A30,A99,AE,AR,V,V1-V30,VE,B,C,D,X)
5. Basis for Request and Type of Revision:
a. The basis for this revision request is(check all that apply)
❑Physical Change 0 Improved Methodology/Data 0 Regulatory Floodway Revision 0 Base Map Changes
❑Coastal Analysis ❑Hydraulic Analysis 0 Hydrologic Analysis 0 Corrections
❑Weir-Dam Changes 0 Levee Certification 0 Alluvial Fan Analysis 0 Natural Changes
❑New Topographic Data ❑Other(Attach Description)
Note: A photograph and narrative description of the area of concem is not required,but is very helpful during review.
b.The area of revision encompasses the following structures(check all that apply)
Structures: 0 Channelization 0 Levee/Floodwall 0 Bridge/Culvert
0 Dam 0 Fill 0 Other(Attach Description)
•
DHS-FEMA Form 81-89,DEC 07 Overview&Concurrence Form MT-2 Form 1 Page 1 of 2
C. REVIEW FEE
as the review fee for the appropriate request category been included? O Yes Fee amount: $
lii
❑ No,Attach Explanation
Please see the DHS-FEMA Web site at http://www.fema.goV/plan/prevent/fhm/frm_fees.shtm for Fee Amounts and Exemptions.
D. SIGNATURE
All documents submitted in support of this request are correct to the best of my knowledge. I understand that any false statement may be punishable by
fine or imprisonment under Title 18 of the United States Code,Section 1001.
Name: Company:
Mailing Address: Daytime Telephone No.: Fax No.:
E-Mail Address:
Signature of Requester(required): Date:
As the community official responsible for floodplain management,I hereby acknowledge that we have received and reviewed this Letter of Map Revision
(LOMR)or conditional LOMR request. Based upon the community's review,we find the completed or proposed project meets or is designed to meet all
of the community floodplain management requirements,including the requirement that no fill be placed in the regulatory floodway,and that all necessary
Federal,State,and local permits have been,or in the case of a conditional LOMR,will be obtained. In addition,we have determined that the land and
any existing or proposed structures to be removed from the SFHA are or will be reasonably safe from flooding as defined in 44CFR 65.2(c),and that we
have available upon request by FEMA,all analyses and documentation used to make this determination.
Community Official's Name and Title: Community Name:
Mailing Address: Daytime Telephone No.: Fax No.:
E-Mail Address:
�Gommunity Official's Signature(required): Date:
CERTIFICATION BY REGISTERED PROFESSIONAL ENGINEER ANDIOR LAND SURVEYOR
This certification is to be signed and sealed by a licensed land surveyor,registered professional engineer,or architect authorized by law to certify
elevation information data,hydrologic and hydraulic analysis,and any other supporting information as per NFIP regulations paragraph 65.2(b)and as
described in the MT-2 Forms Instructions. All documents submitted in support of this request are correct to the best of my knowledge. I understand that
any false statement may be punishable by fine or imprisonment under Title 18 of the United States Code,Section 1001.
Certifier's Name: License No.: Expiration Date:
Company Name: Telephone No.: Fax No.:
Signature: Date:
Ensure the forms that are appropriate to your revision request are included in your submittal.
Form Name and(Humbert Required if...
❑ Riverine Hydrology and Hydraulics Form(Form 2) New or revised discharges or water-surface elevations
❑ Riverine Structures Form(Form 3) Channel is modified,addition/revision of bridge/culverts,
addition/revision of levee/floodwall,addition/revision of dam
❑ Coastal Analysis Form(Form 4) New or revised coastal elevations
9 Coastal Structures Form(Form 5) Addition/revision of coastal structure Seal(Optional)
❑ Alluvial Fan Flooding Form(Form 6) Flood control measures on alluvial fans
0 , ._
DHS-FEMA Form 81-89,DEC 07 Overview&Concurrence Form MT-2 Form 1 Page 2 of 2
iii U.S. DEPARTMENT OF HOMELAND SECURITY-FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.BNo.1660-0016
RIVERINE HYDROLOGY & HYDRAULICS FORM Expires:12/31/2010
PAPERWORK REDUCTION ACT
Public reporting burden for this form is estimated to average 3.25 hours per response. The burden estimate includes the time for reviewing
instructions,searching existing data sources,gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You
are not required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send
comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management,U.S.
Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction
Project(1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not
send your completed survey to the above address.
Flooding Source:
Note:Fill out one form for each flooding source studied
A. HYDROLOGY
1. Reason for New Hydrologic Analysis (check all that apply)
El Not revised(skip to section B) El No existing analysis ❑ Improved data
El Alternative methodology ❑ Proposed Conditions(CLOMR) O Changed physical condition of watershed
2. Comparison of Representative 1%-Annual-Chance Discharges
Location Drainage Area(Sq.Mi.) Effective/FIS(cfs) Revised(cfs)
Methodology for New Hydrologic Analysis (check all that apply)
❑ Statistical Analysis of Gage Records Precipitation/Runoff Model
El Regional Regression Equations Other(please attach description)
Please enclose all relevant models in digital format,maps,computations(including computation of parameters)and documentation to support the
new analysis.
4. Review/Approval of Analysis
If your community requires a regional,state,or federal agency to review the hydrologic analysis,please attach evidence of approval/review.
5. Impacts of Sediment Transport on Hydrology
Was sediment transport considered? ❑Yes El No If yes,then fill out Section F(Sediment Transport)of Form 3. If No,then attach your
explanation for why sediment transport was not considered.
B. HYDRAULICS
1. Reach to be Revised
Description Cross Section Water-Surface Elevations(ft.)
Effective Proposed/Revised
Downstream Limit
Upstream Limit
2. Hydraulic Method/Model Used
DHS-FEMA Form 81-89A,DEC 07 Riverine Hydrology&Hydraulics Form MT-2 Form 2 Page 1 of 2
B. HYDRAULICS(CONTINUED)
3. Pre-Submittal Review of Hydraulic Models
DHS-FEMA has developed two review programs, CHECK-2 and CHECK-RAS, to aid in the review of HEC-2 and HEC-RAS hydraulic models,
respectively. These review programs may help verify that the hydraulic estimates and assumptions in the model data are in accordance with NFIP
requirements,and that the data are comparable with the assumptions and limitations of HEC-2MEC-RAS. CHECK-2 and CHECK-RAS identify
areas of potential error or concern. These tools do not replace engineering judgment. CHECK-2 and CHECK-RAS can be downloaded from
http://www.fema.gov/plan/prevent/fhm/frm soft.shtm. We recommend that you review your HEC-2 and HEC-RAS models with CHECK-2 and
CHECK-RAS. Review of your submittal and resolution of valid modeling discrepancies may result in reduced review time.
4. Models Submitted Natural Run Floodway Run Datum
Duplicate Effective Model' File Name: Plan Name: File Name: Plan Name:
Corrected Effective Model' File Name: Plan Name: File Name: Plan Name:
Existing or Pre-Project Conditions Model File Name: Plan Name: File Name: Plan Name:
Revised or Post-Project Conditions Model File Name: Plan Name: File Name: Plan Name:
Other-(attach description) File Name: Plan Name: File Name: Plan Name:
*For details,refer to the corresponding section of the instructions.
0 Digital Models Submitted?(Required)
C. MAPPING REQUIREMENTS
A certified topographic map must be submitted showing the following information(where applicable):the boundaries of the effective,existing,and
proposed conditions 1%-annual-chance floodplain (for approximate Zone A revisions) or the boundaries of the 1%- and 0.2%-annual-chance
floodplains and regulatory floodway(for detailed Zone AE,AO,and AH revisions);location and alignment of all cross sections with stationing control
indicated;stream,road,and other alignments(e.g.,dams,levees,etc.);current community easements and boundaries;boundaries of the requesters
property; certification of a registered professional engineer registered in the subject State; location and description of reference marks; and the
referenced vertical datum(NGVD,NAVD,etc.).
0 Digital Mapping(GIS/CADD)Data Submitted
Note that the boundaries of the existing or proposed conditions floodplains and regulatory floodway to be shown on the revised FIRM and/or FBFM
must tie-in with the effective floodplain and regulatory floodway boundaries. Please attach a copy of the effective FIRM andlor FBFM,annotated to
show the boundaries of the revised 1%-and 0.2%-annual-chance floodplains and regulatory floodway that tie-in with the boundaries of the effective
1%-and 0.2%-annual-chance floodplain and regulatory floodway at the upstream and downstream limits of the area of revision.
❑ Annotated FIRM and/or FBFM(Required)
D. COMMON REGULATORY REQUIREMENTS*
1. For LOMR/CLOMR requests,do Base Flood Elevations(BFEs)increase? ❑Yes 0 No
a. For CLOMR requests,if either of the following is true,please submit evidence of compliance with Section 65.12 of the NFIP regulations:
• The proposed project encroaches upon a regulatory floodway and would result in increases above 0.00 foot.
• The proposed project encroaches upon a SFHA with or without BFEs established and would result in increases above 1.00 foot.
b. For LOMR requests,does this request require property owner notification and acceptance of BFE increases? 0 Yes 0 No
If Yes,please attach proof of property owner notification and acceptance(if available). Elements of and examples of property owner
notification can be found in the MT-2 Form 2 Instructions.
2. Does the request involve the placement or proposed placement of fill? ❑ Yes 0 No
If Yes, the community must be able to certify that the area to be removed from the special flood hazard area, to include any structures or
proposed structures, meets all of the standards of the local floodplain ordinances, and is reasonably safe from flooding in accordance with the
NFIP regulations set forth at 44 CFR 60.3(a)(3),65.5(a)(4),and 65.6(a)(14). Please see the MT-2 instructions for more information.
3. For LOMR requests,is the regulatory floodway being revised? 0 Yes ❑ No
If Yes,attach evidence of regulatory floodway revision notification. As per Paragraph 65.7(b)(1)of the NFIP Regulations,notification is
required for requests involving revisions to the regulatory floodway. (Not required for revisions to approximate 1%-annual-chance floodplains
[studied Zone A designation]unless a regulatory floodway is being added. Elements and examples of regulatory floodway revision notification
can be found in the MT-2 Form 2 Instructions.)
4. For LOMR/CLOMR requests,does this request have the potential to impact an endangered species? ❑ Yes 0 No
If Yes, please submit documentation to the community to show that you have complied with Sections 9 and 10 of the Endangered Species Act
(ESA). Section 9 of the ESA prohibits anyone from"taking"or harming an endangered species. If an action might harm an endangered species,
a permit is required from U.S.Fish and Wildlife Service or National Marine Fisheries Service under Section 10 of the ESA.
• For actions authorized, funded, or being carried out by Federal or State agencies, please submit documentation from the agency showing its
compliance with Section 7(a)(2)of the ESA.
'Not inclusive of all applicable regulatory requirements. For details,see 44 CFR parts 60 and 65.
OHS-FEMA Form 81-89A,DEC 07 Riverine Hydrology&Hydraulics Form MT-2 Form 2 Page 2 of 2
U.S. DEPARTMENT OF HOMELAND SECURITY-FEDERAL EMERGENCY MANAGEMENT AGENCY O.MBNo.1660-0016
RIVERINE STRUCTURES FORM Expires:12/31/2010
PAPERWORK REDUCTION ACT
Public reporting burden for this form is estimated to average 7 hours per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form. You are not
required to respond to this collection of information unless a valid OMB control number appears in the upper right corner of this form. Send
comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to:Information Collections Management,U.S.
Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington DC 20472, Paperwork Reduction
Project(1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send
your completed survey to the above address.
Flooding Source:
Note:Fill out one form for each flooding source studied
A. GENERAL
Complete the appropriate section(s)for each Structure listed below:
Channelization complete Section B
Bridge/Culvert complete Section C
Darn/Basin complete Section D
Levee/Floodwall complete Section E
Sediment Transport complete Section F(if required)
Description Of Structure
1. Name of Structure:
Type (check one): 0 Channelization 0 Bridge/Culvert ❑Levee/Floodwall 0 Dam/Basin
Location of Structure:
• Downstream Limit/Cross Section:
Upstream Limit/Cross Section:
2. Name of Structure:
Type (check one): 0 Channelization 0 Bridge/Culvert ❑Levee/Floodwall 0 Dam/Basin
Location of Structure:
Downstream Limit/Cross Section:
Upstream Limit/Cross Section:
3. Name of Structure:
Type (check one) ❑Channelization 0 Bridge/Culvert 0 Levee/Floodwall 0 Dam/Basin
Location of Structure:
Downstream Limit/Cross Section:
Upstream LimiUCross Section:
NOTE: For more structures,attach additional pages as needed.
•
DHS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 1 of 10
B. CHANNELIZATION
Flooding Source:
lame of Structure:
1. Accessory Structures
The channelization includes(check one):
❑ Levees[Attach Section E(Levee/Floodwall)] ❑ Drop structures
❑ Superelevated sections ❑ Transitions in cross sectional geometry
❑ Debris basin/detention basin [Attach Section D(Dam/Basin)] ❑ Energy dissipator
El Other(Describe):
2. Drawing Checklist
Attach the plans of the channelization certified by a registered professional engineer,as described in the instructions.
3. Hydraulic Considerations
The channel was designed to carry (cfs)and/or the -year flood.
The design elevation in the channel is based on(check one):
❑ Subcritical flow ❑ Critical flow 0 Supercritical flow 0 Energy grade line
If there is the potential for a hydraulic jump at the following locations,check all that apply and attach an explanation of how the hydraulic jump is
controlled without affecting the stability of the channel.
❑ Inlet to channel ❑ Outlet of channel 0 At Drop Structures ❑ At Transitions
❑ Other locations(specify):
4. Sediment Transport Considerations
Was sediment transport considered? ❑Yes El No If Yes,then fill out Section F(Sediment Transport).
If No,then attach your explanation for why sediment transport was not considered.
• C. BRIDGE/CULVERT
Flooding Source: .
Name of Structure:
1. This revision reflects(check one):
❑ Bridge/culvert not modeled in the FIS
O Modified bridge/culvert previously modeled in the FIS
❑ Revised analysis of bridge/culvert previously modeled in the FIS
2. Hydraulic model used to analyze the structure(e.g.,HEC-2 with special bridge routine,WSPRO,HY8):
If different than hydraulic analysis for the flooding source,justify why the hydraulic analysis used for the flooding source could not analyze the
structures. Attach justification.
3. Attach plans of the structures certified by a registered professional engineer. The plan detail and information should include the following(check
the information that has been provided):
❑ Dimensions(height,width,span,radius,length) El Erosion Protection
O Shape(culverts only) ❑ Low Chord Elevations—Upstream and Downstream
❑ Material ❑ Top of Road Elevations—Upstream and Downstream
❑ Beveling or Rounding El Structure Invert Elevations—Upstream and Downstream
O Wng Wall Angle 0 Stream Invert Elevations—Upstream and Downstream
❑ Skew Angle ❑ Cross-Section Locations
❑ Distances Between Cross Sections
4. Sediment Transport Considerations
Was sediment transport considered? ❑Yes ❑No If yes,then fill out Section F(Sediment Transport).
If No,then attach your explanation for why sediment transport was not considered.
•
DHS-FEMA Form 81-898,DEC 07 Riverine Structures Form MT-2 Form 3 Page 2 of 10
D. DAM/BASIN
Flooding Source:
OName of Structure:
1. This request is for(check one): ❑Existing dam ❑New dam ❑Modification of existing dam
2. The dam was designed by(check one):0 Federal agency ❑State agency 0 Local government agency❑Private organization
Name of the agency or organization:
3. The Dam was permitted as(check one):
a. ❑Federal Dam 0 State Dam
Provide the permit or identification number(ID)for the dam and the appropriate permitting agency or organization
Permit or ID number Permitting Agency or Organization
b. ❑Local Government Dam 0 Private Dam
Provided related drawings,specification and supporting design information.
4. Does the project involve revised hydrology? ❑Yes 0 No
If Yes,complete the Riverine Hydrology&Hydraulics Form(Form 2).
Was the dam/basin designed using critical duration storm?
0 Yes,provide supporting documentation with your completed Form 2.
❑ No,provide a written explanation and justification for not using the critical duration storm.
5. Does the submittal include debris/sediment yield analysis? ❑Yes ❑ No
• If yes,then fill out Section F(Sediment Transport).
If No,then attach your explanation for why debris/sediment analysis was not considered.
6. Does the Base Flood Elevation behind the dam or downstream of the dam change?
❑Yes ❑No If Yes,complete the Riverine Hydrology&Hydraulics Form(Form 2)and complete the table below.
Stillwater Elevation Behind the Dam
FREQUENCY(%annual chance) FIS REVISED
10-year(10%)
50-year(2%)
100-year(1%)
500-year(0.2%)
Normal Pool Elevation
7. Please attach a copy of the formal Operation and Maintenance Plan
•
DHS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 3 of 10
E. LEVEE/FLOODWALL
1. System Elements
• a. This Levee/Floodwall analysis is based on(check one):
❑ upgrading of an existing levee/floodwall system
❑ a newly constructed levee/floodwall system
❑ reanalysis of an existing levee/floodwall system
b. Levee elements and locations are(check one):
❑ earthen embankment,dike,berm,etc. Station to
❑ structural floodwall Station to
❑ Other(describe): Station to
c. Structural Type(check one):
❑ monolithic cast-in place reinforced concrete
❑ reinforced concrete masonry block
❑ sheet piling
❑ Other(describe):
d. Has this levee/floodwall system been certified by a Federal agency to provide protection from the base flood?
❑Yes ❑No
If Yes,by which agency?
e. Attach certified drawings containing the following information(indicate drawing sheet numbers):
1. Plan of the levee embankment and floodwall structures. Sheet Numbers:
2. A profile of the levee/floodwall system showing the
Base Flood Elevation(BFE),levee and/or wall crest and
foundation,and closure locations for the total levee system. Sheet Numbers:
• 3. A profile of the BFE,closure opening outlet and inlet
invert elevations,type and size of opening,and
kind of closure. Sheet Numbers:
4. A layout detail for the embankment protection measures. Sheet Numbers:
5. Location,layout,and size and shape of the levee
embankment features,foundation treatment,floodwall
structure,closure structures,and pump stations. Sheet Numbers:
2. Freeboard
a. The minimum freeboard provided above the BFE is:
Riverine
3.0 feet or more at the downstream end and throughout ❑Yes ❑No
3.5 feet or more at the upstream end ❑Yes O No
4.0 feet within 100 feet upstream of all structures and/or constrictions ❑Yes ❑No
Coastal
1.0 foot above the height of the one percent wave associated with the 1%-annual-chance
stillwater surge elevation or maximum wave runup(whichever is greater).
❑Yes ❑No
2.0 feet above the 1%-annual-chance stillwater surge elevation ❑Yes ❑No
• E. LEVEE/FLOODWALL(CONTINUED)
OHS-FEMA Form 81-89B, DEC 07 Riverine Structures Form MT-2 Form 3 Page 4 of 10
2. Freeboard(continued).
• Please note,occasionally exceptions are made to the minimum freeboard requirement. If an exception is requested,attach documentation
addressing Paragraph 65.10(b)(1)(ii)of the NFIP Regulations.
If No is answered to any of the above,please attach an explanation.
b. Is there an indication from historical records that ice-jamming can affect the BFE? ❑Yes ❑No
If Yes,provide ice-jam analysis profile and evidence that the minimum freeboard discussed above still exists.
3. Closures
a. Openings through the levee system(check one): ❑exists ❑does not exist
If opening exists,list all closures:
Channel Station Left or Right Bank Opening Type Highest Elevation for Type of Closure Device
Opening Invert
(Extend table on an added sheet as needed and reference)
Note: Geotechnical and geologic data
In addition to the required detailed analysis reports,data obtained during field and laboratory investigations and used in the
design analysis for the following system features should be submitted in a tabulated summary form. (Reference U.S.Army
Corps of Engineers[USACE]EM-1110-2-1906 Form 2086.)
4. Embankment Protection
• a. The maximum levee slope landside is:
b. The maximum levee slope floodside is:
c. The range of velocities along the levee during the base flood is: (min.) to (max.)
d. Embankment material is protected by(describe what kind):
e. Riprap Design Parameters(check one): n Velocity ❑ Tractive stress
Attach references
Flow Curve or Stone Riprap Depth of
Reach Sideslope Depth Velocity Straight Toedown
Diao Dso Thickness
Sta to
Sta to
Sta to
Sta to
Sta to
Sta to
(Extend table on an added sheet as needed and reference each entry)
•
DHS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 5 of 10
E. LEVEE/FLOODWALL(CONTINUED)
4. Embankment Protection(continued'
• f. Is a bedding/filter analysis and design attached? ❑ Yes ❑ No
g. Describe the analysis used for other kinds of protection used(include copies of the design analysis):
Attach engineering analysis to support construction plans.
5. Embankment And Foundation Stability
a. Identify locations and describe the basis for selection of critical location for analysis:
❑ Overall height: Sta. ;height ft.
0 Limiting foundation soil strength:
Sta. ,depth to
strength += degrees,c= psf
slope: SS= (h)to (v)
(Repeat as needed on an added sheet for additional locations)
b. Specify the embankment stability analysis methodology used(e.g.,circular arc,sliding block,infinite slope,etc.):
c. Summary of stability analysis results:
• Case Loading Conditions Critical Safety Factor Criteria(Min.)
I End of construction 1.3
II Sudden drawdown 1.0
III Critical flood stage 1.4
IV Steady seepage at flood stage 1.4
VI Earthquake(Case I) 1.0
(Reference: USACE EM-1110-2-1913 Table 6-1)
d. Was a seepage analysis for the embankment performed? ❑Yes ❑ No
If Yes,describe methodology used:
e. Was a seepage analysis for the foundation performed? ❑Yes ❑No
f. Were uplift pressures at the embankment landside toe checked? 0 Yes 0 No
g. Were seepage exit gradients checked for piping potential? 0 Yes 0 No
h. The duration of the base flood hydrograph against the embankment is hours.
Attach engineering analysis to support construction plans.
•
DHS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 6 of 10
E. LEVEE/FLOODWALL(CONTINUED)
. Floodwall And Foundation Stability�
a. Describe analysis submittal based on Code(check one):
❑ UBC(1988) or ❑ Other(specify):
b. Stability analysis submitted provides for:
❑ Overturning ❑ Sliding If not,explain:
c. Loading included in the analyses were:
❑ Lateral earth @ PA= psf; Pp= psf
❑ Surcharge-Slope @ , ❑ surface psf
❑ Wind @ P„.= psf
❑ Seepage(Uplift); ❑ Earthquake @ P„= %g
❑ 1%-annual-chance significant wave height: ft.
❑1%-annual-chance significant wave period: sec.
d. Summary of Stability Analysis Results: Factors of Safety.
Itemize for each range in site layout dimension and loading condition limitation for each respective reach.
Criteria(Min) Sta To Sta To
Loading Condition
Overturn Sliding Overturn Sliding Overturn Sliding
Dead&Wnd 1.5 1.5
"lead&Soil 1.5 1.5
Dead,Soil,Flood,& 1.5 1.5
Impact
Dead,Soil,&Seismic 1.3 1.3
(Ref: FEMA 114 Sept 1986;USACE EM 1110-2-2502)
(Note: Extend table on an added sheet as needed and reference)
e. Foundation bearing strength for each soil type:
Bearing Pressure Sustained Load(psf) Short Term Load(psf)
Computed design maximum
Maximum allowable
f. Foundation scour protection❑is,❑is not provided. If provided,attach explanation and supporting documentation:
Attach engineering analysis to support construction plans.
•
DHS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 7 of 10
E. LEVEE/FLOODWALL(CONTINUED)
7. Settlement
• a. Has anticipated potential settlement been determined and incorporated into the specified construction elevations to maintain the
established freeboard margin? ❑Yes ❑No
b. The computed range of settlement is ft.to ft.
c. Settlement of the levee crest is determined to be primarily from:
❑ Foundation consolidation
❑ Embankment compression
❑ Other(Describe):
d. Differential settlement of floodwalls ❑ has ❑ has not been accommodated in the structural design and construction.
Attach engineering analysis to support construction plans.
8. Interior Drainage
a. Specify size of each interior watershed:
Draining to pressure conduit: acres
Draining to ponding area: acres
b. Relationships Established
Ponding elevation vs.storage 0 Yes ❑No
Ponding elevation vs.gravity flow ❑Yes ❑No
Differential head vs.gravity flow 0 Yes ❑No
c. The river flow duration curve is enclosed: 0 Yes ❑No
d. Specify the discharge capacity of the head pressure conduit: cfs
• e. Which flooding conditions were analyzed?
• Gravity flow(Interior Watershed) ❑Yes ❑No
• Common storm(River Watershed) ❑Yes 0 No
• Historical ponding probability ❑Yes 0 No
• Coastal wave overtopping 0 Yes 0 No
If No for any of the above,attach explanation.
f. Interior drainage has been analyzed based on joint probability of interior and exterior flooding and the capacities of pumping and outlet
facilities to provide the established level of flood protection. ❑Yes ❑No
If No,attach explanation.
g. The rate of seepage through the levee system for the base flood is cfs
h. The length of levee system used to drive this seepage rate in item g: ft.
•
DHS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 8 of 10
E. LEVEEIFLOODWALL(CONTINUED)
8. Interior Drainage(continued)
• i. Will pumping plants be used for interior drainage? ❑Yes ❑No
If Yes,include the number of pumping plants:
For each pumping plant,list:
Plant#1 Plant#2
The number of pumps
The ponding storage capacity
The maximum pumping rate
The maximum pumping head
The pumping starting elevation
The pumping stopping elevation
Is the discharge facility protected?
Is there a flood waming plan?
How much time is available between warning
and flooding?
Will the operation be automatic? ❑Yes ❑No
If the pumps are electric,are there backup power sources? ❑Yes 0 No
(Reference: USACE EM-1110-2-3101,3102,3103,3104,and 3105)
Include a copy of supporting documentation of data and analysis. Provide a map showing the flooded area and maximum ponding elevations for all
einterior watersheds that result in flooding.
. Other Design Criteria
a. The following items have been addressed as stated:
Liquefaction 0 is 0 is not a problem
Hydrocompaction 0 is 0 is not a problem
Heave differential movement due to soils of high shrink/swell 0 is 0 is not a problem
b. For each of these problems,state the basic facts and corrective action taken:
Attach supporting documentation
c. If the levee/floodwall is new or enlarged,will the structure adversely impact flood levels and/or flow velocities floodside of the structure?
❑Yes ❑No
Attach supporting documentation
d. Sediment Transport Considerations:
Was sediment transport considered? ❑Yes ❑No If Yes,then fill out Section F(Sediment Transport).
If No.then attach your explanation for why sediment transport was not considered.
.
DHS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 9 of 10
E. LEVEE/FLOODWALL(CONTINUED)
10. Operational Plan And Criteria
a. Are the planned/installed works in full compliance with Part 65.10 of the NFIP Regulations? ❑Yes ❑No
b. Does the operation plan incorporate all the provisions for closure devices as required in Paragraph 65.10(c)(1)of the NFIP regulations?
❑Yes ❑No
c. Does the operation plan incorporate all the provisions for interior drainage as required in Paragraph 65.10(c)(2)of the NFIP regulations?
❑Yes ❑No
If the answer is No to any of the above,please attach supporting documentation.
11. Maintenance Plan
a. Are the planned/installed works in full compliance with Part 65.10 of the NFIP Regulations? ❑Yes ❑No
If No,please attach supporting documentation.
12. Operations and Maintenance Plan
Please attach a copy of the formal Operations and Maintenance Plan for the levee/floodwall.
F. SEDIMENT TRANSPORT
Flooding Source:
Name of Structure:
If there is any indication from historical records that sediment transport(including scour and deposition)can affect the
Base Flood Elevation(BFE);and/or based on the stream morphology,vegetative cover,development of the watershed and bank conditions,there is
a potential for debris and sediment transport(including scour and deposition)to affect the BFEs,then provide the following information along with the
supporting documentation:
Sediment load associated with the base flood discharge: Volume acre-feet
•ebris load associated with the base flood discharge: Volume acre-feet
Sediment transport rate (percent concentration by volume)
Method used to estimate sediment transport:
Most sediment transport formulas are intended for a range of hydraulic conditions and sediment sizes;attach a detailed explanation for using the
selected method.
Method used to estimate scour and/or deposition:
Method used to revise hydraulic or hydrologic analysis(model)to account for sediment transport:
Please note that bulked flows are used to evaluate the performance of a structure during the base flood;however,FEMA does not map BFEs based
on bulked flows.
If a sediment analysis has not been performed,an explanation as to why sediment transport(including scour and deposition)will not affect the BFEs
or structures must be provided.
•
DI-IS-FEMA Form 81-89B,DEC 07 Riverine Structures Form MT-2 Form 3 Page 10 of 10
•
TAB 6 - HYDROLOGY DATA
1. RAINFALL DATA
2. URBAN DRAINAGE AND FLOOD CONTROL EXCEL SPREADSHEET
LINK
•
•
DRAINAGE CRITERIA MANUAL (V. 1 ) RAINFALL
411
R 71 w 0.95 R 70 W R 69 W R 68 W R 67 W R 66 W R 65 W R 64 W R 63 W
0.8 0.9 1 .0 1 .0 0.95
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Figure RA-1—Rainfall Depth-Duration-Frequency: 2-Year, 1 -Hour Rainfall
• Rev. 01/2004 RA-13
Urban Drainage and Flood Control District
RAINFALL DRAINAGE CRITERIA MANUAL (V. 1 )
IIII
R 71 W J R 70 W R 69 W R 68 W R 67 W R 66 W R 65 W R 64. W R 63 W
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Figure RA-2—Rainfall Depth-Duration-Frequency: 5-Year, 1-Hour Rainfall 0 RA-14 01/2004
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1 ) RAINFALL
•
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Figure RA-3—Rainfall Depth-Duration-Frequency: 10-Year, 1 -Hour Rainfall 411 Rev. 01/2004 RA-15
Urban Drainage and Flood Control District
RAINFALL DRAINAGE CRITERIA MANUAL (V. 1 )
•
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Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1 ) RAINFALL
Ill
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Figure RA-5—Rainfall Depth-Duration-Frequency: 50-Year, 1 -Hour Rainfall III Rev. 01/2004 RA-17
Urban Drainage and Flood Control District
RAINFALL DRAINAGE CRITERIA MANUAL (V. 1 )• R 71 W R 70 W R 69 W R 68 W R 67 W R 66 W R 65 W R 64 W R 63 W
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RA-18 01/2004
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1 ) RAINFALL Ill R 71 W R 70 w R 69 W R 68 W R 67 w R 66 w R 65 W R 64 w R 63 W
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Urban Drainage and Flood Control District
RAINFALL DRAINAGE CRITERIA MANUAL (V. 1 )Ill 1 .7 2.0 1 .9
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Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1 ) RAINFALL
ID
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Urban Drainage and Flood Control District
RAINFALL DRAINAGE CRITERIA MANUAL (V. 1 )
• R 71 w R 70 w R 69 w R 68 w R 67 W R 66 W R 65 w R 64 w R 63 W
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0 RA-22 01/2004
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1 ) RAINFALL IP R 71 W R 70 W R 69 W R 68 W R 67 W R 66 W R 65 W R 64 W R 63 W
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Figure RA-11—Rainfall Depth-Duration-Frequency: 50-Year, 6-Hour Rainfall
IllRev. 01/2004 RA-23
Urban Drainage and Flood Control District
RAINFALL DRAINAGE CRITERIA MANUAL (V. 1 )• R71 W R70W R69W R68W R67W R66W R65W R64W R63W
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Figure RA-12—Rainfall Depth-Duration-Frequency: 100-Year, 6-Hour Rainfall
411 RA-24 01/2004
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL(V. 1) RAINFALL
• 6
5
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DURATION (HOURS)
Figure RA-13—Rainfall Depth-Duration-Frequency: Precipitation Depth-Duration
Nomograph For Use East of Continental Divide
• Rev. 01/2004 RA-25
Urban Drainage and Flood Control District
RAINFALL DRAINAGE CRITERIA MANUAL(V. 1)
• 100.
24-hr.
Z 90
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• EXTRAPOLATED CURVE
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0 50 100 150 200 250 300
AREA (SQUARE MILES)
Figure RA-14—Depth-Area Adjustment Curves
• RA-26 01/2004
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL(V. 1) RAINFALL
•
10
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8
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3
2-yr rainfall=.0.95 inch
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Time(minutes)
Figure RA-15—Rainfall Intensity-Duration Curves
Rev. 01/2004 RA-27
Urban Drainage and Flood Control District
Rational Formula-Based Modified FAA Procedure
• The FAA detention sizing method provides a reasonable estimate of on-site detention
storage volume requirements. Figure 5 in Section 3.1.4 of this Preliminary Drainage
Study provides a preliminary estimate of percentage of area required for proposed
detention areas based on the FAA method. The theory and equations required to
compute the detention volume based on the FAA method is explained in detail in the
Urban Storm Drainage Criterial Manual. However, Urban Drainage also supplies an
Excel spreadsheet on their website that computes detention volumes based on the FAA
Method. This Excel spreadsheet can be downloaded from the following website:
http://www.udfcd.org/downloads/down_sofware.htm
•
•
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