HomeMy WebLinkAbout20143070.tiff Sco/' /n1Br,6Le-
SITE SPECIFIC DEVELOPMENT PLAN AND USE BY SPECIAL
REVIEW (USR) APPLICATION
FOR PLANNING DEPARTMENT USE DATE RECEIVED:
RECEIPT#/AMOUNT# /8 CASE#ASSIGNED:
APPLICATION RECEIVED BY PLANNER ASSIGNED:
Parcel Number 0 5 0 5 -_I D - I - OD - o9O
0
(12 digit number-found on Tax I.D. information,obtainable at the Weld County Assessor's Office,or wowv.co.weld.co.us)
Legal Description e "S A, Mi£.5078
Zoe /j Section '/, Township North, Range_West
Zone District: Ai Total Acreage: 4./0 (^7 0, Flood Plain: /v , Geological Hazard: A-10 ,
Airport Overlay District: /1/0
FEE OWN
y/ER(S)OF THE PROPERTY:
Name: fiekrl /nos f Jc✓i e I e%/.5
Work Phone# Home Phone# Email
Address: //a 1b ,4%r dcres ,Dr
Address:
City/State/Zip Code rreefy f0 804,3/
Applicant Name: Scott McBride
Work Phone# 970-214-6788ome Phone# Email scott@polyguardcovers.com
Address:
Address: 2200 San Miguel Drive, Severance, CO 80550
City/State/Zip Code
Name:
Work Phone# Home Phone# Email
Address:
Address:
City/State/Zip Code
APPLICANT OR AUTHORIZED AGENT (See Below:Authorization� must accompany o7 applications signed by Authorized Agent)
Name: A7 at/ t /`r t,✓/a-/%5 ✓.7/ti r ' a le. ZL(
Work Phone 4 Home Phone 4
/ Email
Address:, 46)0 J5 i/G girt,t /'4
Address:
City/State/Zip Code rva-r s Co 800z0
PROP SE USE: J
RV.s�.� to ,n eldc. Ri /raiers )Jdt S1>s , . o.a /nod.<s
<y�•B$nzer �� 1;s{crcA- Cots,/LA/uc,ks OO Jar .C li<<,caCg_ Cafe, faL.'s
gesed/K-L. mi a me .K4 Y',) a �7 O y L1a c,.s, /VC C.vinmr VC',c:ai lcc. /
J
I (We)hereby depose and state under penalties of perjury that all statements, proposals, and/or plans submitted
with or contained within the application are true and correct to the best of my(our)knowledge. Signatures of all
fee owners of property must sign this application. 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 indica 'ag that the signatory has toleg pl ,uthority to sign for the corporation.
t______
0 8
Signature: 0uthorized Agent Date Signature: Owner or Authorized Agent Date
csio\-4- (SVicl
' DEPARTMENT OF PLANNING SERVICES
1555 N 17th AVE
GREELEY, CO 80631
PHONE: (970) 353-6100, Ext. 3540
COLORADO• FAX: (970) 304-6498
k-b a-ooKcAUTHORIZATION FORM
r '!GlU/'/ A(44/S gilt('
(�
I 1 rfAL 1 AtAOe-- represent - ^c id rc A_ ai-TS for the property
(AgenVApplicaal) ( wn r)
located at 9 i.��S WCti 27
LEGAL DESCRIPTION: SEC 3 0 TWN 6' RNG v 6 !!
SUBDIVISION NAME: /Uri LOT( 4 BLK /12/4-
I can be contacted at the following phone#'s: Home ( )0,1 730 - 070 K
Work
Fax#
The property owner can be contacted at the following phone#'s
cl c(7O- _?a,2-34/1
Work Work / /(1 Jt'yYY c 6-da
Fax# (77(7-
Correspondence mailed to (only one): )g Agent/Applicant
Property Owner
DATE /1 __ }`1/ —/`'/
OWNER'S SIGNATURE tiac<_.7)
SITE SPECIFIC DEVELOPMENT PLAN AND USE BY SPECIAL REVIEW (USR) QUESTIONNAIRE
1. EXPLAIN IN DETAIL THE PROPOSED USE OF THE PROPERTY
The proposed project is to construct a full service RV and Boat storage facility. The secured facility will offer a
one-stop dump station and water hydrant. Allowing RV owners to fill up before they travel and clean out when
they return. The facility will contain an onsite manager located within a mobile home building. The property
will be secured with a 6 foot chain link fence, lighting, automatic keypad entry/exit gates, and video cameras.
The current remains would be cleared and the property graded to provide a smooth flat surface with a slight
grade to the southeast for drainage. The surface will be covered with 4" to 6" of recycle asphalt. The facility will
provide storage for an estimate of up to 300 RVs/Boats.The covered storage spaces are located on the western
side of the site.The proposed covered storage on the very western side of the site will accommodate 37-40'
parking stalls and 5-50' parking stalls for a total of 42 storage stalls.The next row to the east is also considered
proposed future covered storage and will accommodate 31-40' parking stalls,these storage stalls may be
divided in half into 20' stalls.
2. Explain how this proposal is consistent with the intent of the Weld County Code, Chapter 22 of the
Comprehensive Plan. Weld County is diverse physically and culturally in its land use. Land use changes are
occurring, and agriculturally zoned land is being changed to residential, commercial and industrial development.
Consequently, it is the goal of the Comprehensive Plan to provide benefits and promote opportunities for
County citizens. Wherefore,this proposal to transform farm land that is adjacent to a higher-end-scale urban
community into a full service RV, Boat and Vehicle Storage is both favorable and useful. It contributes to the
opportunities for the local and broader County citizens.This proposed land use is consistent with the master
plan and the North Greeley Rail Corridor Subarea Plan for the physical development of the unincorporated
territory of Weld County, and is in compliance with all rules and regulations of Weld County.
This Proposal will also facilitate a buffer between the current urban community and the potential high impact
industrial development of the future surrounding area along the Rail Corridor.The full service RV, Boat and
Vehicle Storage is a low impact development with low-level noise, producing very minimal dust. A tree and
foliage landscape will surround the facility enhancing visual sight in the area, and it will aid in the buffer.
3. Explain how this proposal is consistent with the intent of the Weld County Code, Chapter 23(Zoning)and the
zone district in which it is located.
The farm land currently zoned "Agricultural" will be Zoned, at a later date, as Industrial per the Comprehensive
Plan for the North Greeley Rail Corridor Subarea.
Sec. 23-3-310. I-1 (Industrial) Zone District.
A. Intent.The purpose of the Industrial Zone District is to provide a zone to accommodate industrial USES which
create minimal negative visual impacts.
B. Uses Allowed:
1. Areas for parking passenger vehicles.
2. UTILITY SERVICE FACILITIES.
3. Disposal of DOMESTIC SEPTAGE
4. Parking areas or STRUCTURES for passenger vehicles with a gross vehicle weight less than six thousand (6,000)
pounds only when the vehicles are SCREENED from the ADJACENT public rights-of-way or on ADJACENT
properties.
5. RECREATIONAL FACILITIES for the USE of persons employed in the conduct or maintenance of the USES
allowed on the property.The full service RV, Boat and Vehicle Storage meets Sec. 23-3-310. I-1 (Industrial)
Zoning requirements.
4. What type of uses surround the site:To the south is the Bracewell PUD which consist of high end Homes (south
of WCR 64.5). North of WCR 64.5 and south of the railroad ROW are 4 Home sites. To the west and north is farm
ground which is planted in Row Crops.To the east is a Home site which is located on a large lot. This lot is
planted in a hay crop,the house is located±350' east from WCR 27.
5. Describe, in detail,the following
Number of people who will use this site: 300 to 400 RV/Boat owners, the number of persons that visit the site
on a daily bases will vary greatly, during the week,Tuesday thru Thursday, the number of people visiting the site
will be relatively low, 2 to 4 per day. From Friday thru Monday the number of people visiting the site will
increase greatly, 20 to 40 per day. Holiday weekends will see the greatest number of people visiting the site to
pick-up or drop-off R.V., boats and other recreational vehicles at the site and could approach 100 to 150 people
per day.
Number of employees proposed to be employed at the site: 2
Hours of Operation: 24 hours a day 7 days a week, access will be by key pad controlled gates.
Type and Number of Structures to be erected on the site: Modular Housing unit (Care Taker), part of the
Storage Spaces will be covered and will consist of two roof systems.
Type and number of animals: none
Kind of Vehicles: RV, Boat, other recreational type vehicles and trailers, No "Project Cars/Trucks" will be stored
on site. All items stored on site will be have current registration/permits.
Type,size and access of units:The storage will be for"registered" and insured boat, RV, and vehicle storage.
Customers will have to provide proof of current registration and insurance. All vehicles will have to be operating
and in good condition. The property will not allow junk vehicles that are not registered or do not operate. This
is designed to provide services and convenience not currently offered and for those that appreciate and use
their RVs, Boats, and other vehicles. Access of units will be seasonal and vary by owner. Typically access on
Wednesday/Thursday prior to a trip and return Mon/Tues after a trip. The covered storage spaces are located
on the western side of the site. The proposed covered storage on the very western side of the site will
accommodate 37-40' parking stalls and 5-50' parking stalls for a total of 42 covered storage stalls. The next row
to the east is also considered proposed future covered storage and will accommodate 31-40' parking stalls,
these storage stalls may be divided in half into 20' stalls for a total of up to 62-20' storage spaces.
Who will provide fire protection: Windsor/Severance Fire Protection District.
Water Source on the property: North Weld Water(domestic)
Sewage Disposal system on the property: Septic for the modular Housing unit,The storage yard will utilize a
Privy placed over one of the holding tanks for the R.V. dump station.The R.V. Dump station has been designed
with 7,500 gallons of storage. Permits for both systems have been completed, however,they will not be turned
in to the Health Department until the USR is approved, at that time,the ownership of the parcel will be
transferred to Scott McBride.
If storage or warehousing what type of items: RV, Boat, other recreational types of vehicles and trailers.
6. Explain the proposed landscaping:
LANDSCAPE PLAN:
A recycled asphalt surface material will be spread and packed to provide an all-weather driving and parking
surface free of weeds. The east and south perimeters will be lined with berms, if site soils are available, covered
in dry land grass, attractive screening trees and shrubs providing travelers along WCR 27 an attractive view.
The proposed 6' security fence is not being proposed for screening proposes. The proposed screening trees
along the southern property line will provide screening for the Bracewell PUD Subdivision and the properties
located on the southern side of the Rail Road right of way. The northern and western sides will also have
screening trees, however they will not be as dense as the eastern and southern sides as the visual impact on
farm ground is less of an impact. A landscape plan and landscape maintenance plan is part of this submittal.
7. Reclamation: If and when the USR is abandon,the site could be stripped of the proposed recycled asphalt
surface and re-leveled to the original condition. What is more likely to happen is the site will be redeveloped as
an industrial use, this is due to its location in the North Greeley Rail Corridor Subarea and being adjacent to the
railroad tracks.
8. Explain how storm water drainage will be obtained:A Final Drainage Report/Site Grading Plan has been
prepared for the site. As stormwater does not historically leave this site, a retention pond has been designed
into the eastern portion of the site to accommodate the increased site runoff from the proposed development.
9. Explain How long it will take to construct this site and when construction and landscaping is scheduled to
begin. Site construction and grading will commence upon the USR approval and grading permit. At the present
time it can be difficult to obtain subcontractors to provide the requested services, also portions of the site
improvements can be affected by the seasonal conditions. I is hoped that the landscaping can be completed by
early to mid-fall, however it is assumed that the landscaping will be complete by mid-spring of the coming year.
10. Stock piles: no stock-pile or other types of storage is proposed on the site except for the R.V./boat storage.
11. Please list all proposed on-site and off-site improvements: 6 foot Chain-link security fencing with key code
access gates (2 each, 1 entrance and one exit), one modular housing unit used as a care-takers residence, one
septic system for the modular, one dump station with five (5) 1,500 gallon septic tanks used as holding tanks,
one proposed privy place on top of the last holding tank of the dump station, retention facilities which include
one retention pond and emergency spillway,the landscaping will consist of±100 trees and±110 shrubs planted
around the site and native prairie grasses. Two culverts will be place at the two proposed access points (one
entrance and one exit).
The time line for the completion of the proposed development is dependent upon when the USR is approved
and the season. It is hoped that the site can be constructed in the fall of 2014 and be completed within 45 days
of the approved USR.This time schedule is dependent on being able to get contractors in place and their time
tables.After the USR is approved, more definitive time table can be provided if requested.
r��, ti� Weld County Public Works Dept.
3 - 1111HStreet ACCESS PERMIT
P.O. Box 758
GeV' • 4c- Greeley, CO 80632 APPLICATION FORM
�/C WO Phone: (970)304-6496
Fax: (970)304-6497
Applicant Property Owner(If different than Applicant)
Name sO? 7226erile- Name
Company �es/34p J2 TcyC Address
Address �,WO n/V i ,c/ dr City State_ Zip
City 11--)/n/5Or' State ('C) Zip 8OSS0 Phone
Business Phone C/ 70 -2/1- lm 758 Fax
Fax E-mail
E-mail 3(O2/71 Q,/0D/UQ!laco/Co 'et5.Lion ♦= Existing Access A= Proposed Access
Parcel Location &Sketch
The access is on WCR 2 7
Nearest Intersection:WCR oZ7 &WCR (s'/5' WCR t 4,
Distance from Intersection X0O c
+- ±750
Parcel Number OS 053610009O
Section/Township/Range 30 6, 6 eP t C ,e
Is there an existing access to the property AYES NO® Es..I
JJ Number of Existing Accesses 0 e fine d' -7,73---k
(toad Surface Type&Construction Information - - -�`
Asphalts Gravel Treated n Other wcRt,4J1(AKA "O 'Std
Culvert Size&Type /-/2 ydorfh /-IA a$O,,,jk
Materials used to construct Access -5./c SO,4 get/c/t//Lyle-(4) din
Construction Start Date 113D Finish Date 773 D
Proposed Use
[Temporary (Tracking Pad Required)/$75 ['Single Residential/$75 ❑Industrial/$150
v[ mall Commercial or Oil &Gas/$75 ['Large Commercial/$150 ❑Subdivision/$150
['Field (Agriculture Only)/Exempt
Is this access associated with a Planning Process? ONo Llus^ nRE QPUD Other
Required Attached Documents
- Traffic Control Plan -Certificate of Insurance -Access Pictures(From the Left, Right,& into the access)
By accepting this permit,the undersigned Applicant, under penalty of perjury,verifies that they have received all pages of the permit
application;they have read and understand all of the permit requirements and provisions set forth on all pages;that they have the
authority to sign for and bind the Applicant, if the Applicant is a corporation or other entity;and that by virtue of their signature the
Applicant is bound by and agrees to comply with all said permit requirements and provisions,all Weld County ordinances,and state laws
regarding facilities construction.
Signature Printed Name Date
Approval or Denial will be issued in minimum of 5 days. Approved by
Revised Date 6/29/10
Use by Special Review (USR) Traffic Narrative
Lot "A"RE 5078
The proposed USR is for RV storage and a care-takers residence.
The number of trips generated by the care-takers residence is assumed to be 4.5 trips per day, and the
assumed peak hour trip generation is 1 peak hour trip.
The RV storage yard has the storage capacity of up to 300 RV/boats (design is 283).
During the week there will be little to no traffic generated from the site, assuming 1% of 300 = 3. If three
(3)visits to the site to pick-up or drop-off a RV or boat was performed, this would produce a trip
generation of six (6)for the day. Assume a two (2) Peak Hour Trip generation.
Friday evenings and Sunday evenings would see an increase of traffic at the site. Assuming a 10%
utilization of the RV/boats for the weekend, 30 units would leave the site on Friday, one (1) in and one (1)
out, for a total of 60 trips. It is assumed that these trips would be spread throughout the day with a higher
concentration on Friday evening and again on Sunday evening. Assume 10 Peak Hour Trip generation for
the site.
Holiday weekends would generate the largest trips generated at the site. Assume a 33% usage rate for
the RV/Boats on the site, 100 or a trip generation of 200. It is assumed that these trip generations would
be spread out over Thursday and Friday and again on Sunday, Monday and Tuesday when people return
home. It is difficult to determine what the actual traffic counts would be on any given day during this
period as some people will take extended weekends on the holiday weekends. The peak hour trip
generation could be as low as 10 or as high as 40. An onsite traffic count may be the only method to
determine the peak hour Trip Generation for the site on the holiday weekends. There would only be three
to four weekends per year that would generate the high traffic counts.
Using the average traffic counts for a given year, the Peak Hour Trip generation should be below 20.
At the present time it is assumed that 75% of the traffic will enter the site from the south on WCR 27 then
60%will travel east to the Greeley area by the use of"O" St. (WCR 64) and 15% will travel west to the
Windsor area using WCR 64. The remaining 25% will be accessing/leaving the site from the north using
WCR 27 and traveling north to Highway 392.
If and when Weld County closes the Railroad crossing on WCR 27, all traffic will access/exit the site
from/to the north. The site design has account for this possible scenario with the retention pond design as
the retention pond has been designed to allow for a cul-de-sac at the point that now exist as a railroad
crossing.
Use by Special Review (USR) Dust Abatement Plan
Lot "A"RE 5078
Dust will controlled on site by reduced speeds, Speed Limit 5 Miles per hour.
Additional dust control will be obtained by the use water as needed or by the use of dust inhibitors applied
on traffic areas annually and/or as needed.
The proposed Recycled Asphalt drive surface will also help in dust reduction. The application of water
during the driest parts of the year may be all that is required to control dust at the site.
Use by Special Review (USR) Waste Handling Plan
Lot "A"RE 5078
A trash enclosure has been located on the site at a location specified by the owner.
When the building/Site is occupied, trash service will be provided by
Company Bunting
Account # 126943
Phone # 970 353-2392
The Sanitary Dup station is located inside the fence of the RV storage yard. A Dump
station operating plan has been created and is attached to this USR application.
No other waste are produced at this site.
EMERGENCY CONTACT INFORMATION
PLEASE TYPE OR PRINT
Business Name: /fest4 Sop S/<'raj t Phone: 970 -<2/171-6. 7S8
Address:
Business Owner: -<CO 71 /n[:11,-,ie_ Phone: 970 -2/V - 675-8
Home Address: 06 /2'5) it e' /— City: 64 ndsd r CO a OS S O
List three persons in the order to be called in the event of an emergency:
NAME TITLE ADDRESS PHONE
[ h[ ' I /
�C[i// � �J.',c r_ Wit.„�P� !ZL[i ,SFn /✓J: C` c<r( i 97c l/°f- t.'75
✓Aeo, M[&/de. Q exit)t,-,r 22 o Son ln,4,4e_/ 1).-2re 97o 2A, -6,75-7
// lt),n</Sor C C� UDg305-5-0Business Hours: c2y"�!7r•- Days: 7
Type of Alarm: None E Burglar ❑ Holdup 9 Fire❑Silent❑ Audible❑
Name and address of alarm m company: '�/A
Location of Safe: /�/�
MISCELLANEOUS INFORMATION:
Number of entry/exit doors in this building: Location(s): / o/6A /-so4-4-4 5'd 6'S
Is alcohol stored in building? AM Location(s):
Are drugs stored in building? N U Location(s):
Are weapons stored in building? /VU Location(s):
The following programs are offered public service of the Weld County riffs Office. Please indicate the
programs of interest. II Physical Security Check n Crime Prevention Presentation
UTILITY SHUT OFF LOCATIONS:
Main electrical: 1-.8 l'0
Gas shut off: T 6 O
Exterior water shutoff: / -B 0 _ O /nek r
Interior water shutoff: 'ra�
FOR COMMERCIAL SITES, PLEASE COMPLETE THE FOLLOWING INFORMATION:
BUSINESS EMERGENCY INFORMATION
BUSINESS NAME: Rest Stop Storage PHONE 970-214-6758 (will change once landline installed)
Address: not yet designated
Business Owner: Scott McBride 970-214-6758
Home Address: 2200 San Miguel Drive, Windsor, CO 80550
List 3 people in the order to be called in the event of an emergency
Scott McBride Owner 2200 San Miguel Drive, Windsor, CO 80550 970-214-6758
Shani McBride Owner 2200 San Miguel Drive, Windsor, CO 80550 970-214-6759
Business hours: 24 hours Days: 7 Days a week
Type of alarm: N/A
Location of safe: N/A
MISCELLANEOUS INFORMATION:
Number of entry/exit doors in the building: 2 for the mobile home Front and Back
Is Alcohol Stored: No
Are drugs stored: No
Are weapons stored: No
Utility Shut off Locations:
Main Electrical TBD
Gas Shut off TBD
Exterior Water Shut off TBD
Interior Water Shut off TBD
Final Drainage Report
Reststop Storage
Scott McBride, Owner
31555 WCR 27.
Greeley, CO
June 11, 2014
"1 hereby certify that this report for the final drainage design of Reststop Storage was
prepared by me (or under my direct supervision) in accordance with the provisions of the
Weld County storm drainage criteria for the owners thereof."
Mark A. Taylor
Registered Professional Engineer
State of Colorado No. 46065
1
Table of Contents
I. General Location 3
A. Location 3
B. Description of Property 3
II. Drainage Basins and Sub-basins 3
A. Major Basin Description 3
B. Sub-Basin Description 4
III. Drainage Design Criteria 4
A. Regulations 4
B. Development Criteria References and Constraints 5
C. Hydrological Criteria 5
D. Hydraulic Criteria 5
IV. Drainage Facility Design 5
A. General Concept 5
B. Specific Details 5
V. Conclusions 6
A. Compliance with the Weld County CODE 6
B. Drainage Concepts 6
Appendix A
Table of Contents
Page Data
1 — 1 Vicinity Map
1 - 7 Site Soil Survey Data
I —6 Rational Method and Retention Pond calculations
I. General Location
A. Location
1. The Final Plan Drainage Report is for a parcel located in part of the
North half of Section 30, Township 6 North, Range 66 West of the 6th
P.M.
2. Weld County Road 27 is located along the eastern side of the parcel.
Railroad ROW is located to the southwest of the parcel and just north
of WCR 64 %. The access to the site is by the use WCR 27. This
railroad crossing may possibly be closed by Weld County at a future
date. This grading plan accounts for the future road configuration.
3. There are no major open channels, lakes, or irrigation facilities within
or adjacent to the proposed development. The proposed changes do not
adversely affect the site.
4. The areas to the west, north and east are undeveloped and are areas
that are farmed. WCR 27 is located just to the east of the site. There
is a railroad ROW just to the south of the parcel.
B. Description of Property
1. The area covered in this drainage report is approximately 6.24 acres.
2. The existing ground cover, on the site is sparse as the site was tilled
and is presently fallow. Some low weeds do exist on the development
site. The site has two soil types, Kim loam and Onley fine sand loam,
and both are type B (Hydrologic soil type).
3. There are no major open channels on or adjacent to the site.
4. The proposed site development would consist approximately 285
storage stalls for recreation vehicle, a caretaker unit, RV dump site and
a retention pond. Recycled asphalt will be used for the drive surfaces
of the development. The proposed road center lines will generally
follow the existing ground elevations and will follow the existing
natural flow patterns from the northwest to the southeast. Storm water
facilities for the site will be retention pond which is located at the low
point of the site near WCR 27.
5. There are no irrigation facilities on this site. Local concrete irrigation
ditch on adjacent property to the north and west of site.
6. The ground water table is assumed to be just below the surface as
moist to saturated soils are present in the low area of the site near
WCR 27.
II. Drainage Basins and Sub-Basins
A. Major Basin Description
1. Weld County Public Works was contacted in regards to existing
drainage reports and Master Drainage plans in the area. No
information was available. The site is within the "North Greeley Rail
Corridor Subarea Plan" and there are no drainage studies referenced in
the plan.
3
2. The site is located in the Cache La Poudre River basin. The site is
approximately %2 mile north of the floodplain on Community Panel
080266 0608 C.
3. There are no irrigation facilities on this site. Local concrete irrigation
ditch is located on western and northern sides of the site.
4. The drainage plan has 2 foot existing and proposed contours for the
proposed development and retention pond area.
B. Sub-Basin Description
1. The historic drainage pattern of the site is as follows. In general
Stormwater flows at this site flow to the Southeast at 1.0 to 1.5%
grades. At this time there is no culvert under WCR 27 at the low point
of the site and there is nowhere for storm water flows to drain, so a
retention pond was used to detain storm flows on the site.
2. Topographic data has been obtained for the project to a minimum of
50 feet beyond the limits of the subdivision. Topographic data, to the
east, was obtained out to include WCR 27. Offsite storm water flows
from the north are routed around the site by a irrigation ditch on the
parcel to the north and west of this site. Off-Site drainage from the
north and west has little to no impact during most storm events.
III. Drainage Design Criteria
A. Regulations
1. The 10 and 100 year storm events were used to design and develop
the drainage system for this development per the Weld County
regulations.
2. There are no existing master drainage studies or plans for the area.
The site is surrounded by irrigated farming to the north and west
that would have minimal flows on to this site. To the east is WCR
27 and to the south of the site is Colorado and Southern Railroad
ROW and tracks.
3. The proposed drainage pattern will be as follows: the site will
generally have sheet flow and small swale flows to the retention
pond located at the low point of the site just west of WCR 27.
4. No request for variances is being requested; however the choice of
retention over detention will be discussed in this section. The
owner and developer have requested the use of retention pond for
storm water facilities for this site. Detention was examined and the
site has no historic release for drainage flows. There are no
culverts under WCR 27 or the Railroad ROW and the property to
the south and east of the site are higher than this site. With no
release for a detention pond the use of a retention pond is a viable
solution. The site soils, by a site open hole inspection, are very
well drained, sandy loam. The assumed percolation rate at the site
is assumed to be approximately 15 min. /in. Using 15 min. /in. and
4
a ponding depth of 5.65 feet, the retention pond would drain in
16.8 hours. The use of the retention pond would likely have an
effect on the local water table during large storm events, the effects
would be short term. The existing ground water elevation is
assumed to be approximately 2 feet below the existing ground
elevation and this value was obtained from the property owner. A
benefit of using a retention pond is there will be no impact on the
drainage system downstream of the site. During the 100 year
storm event, flood waters may flow into the proposed retention
pond, as it is over sized by a safety factor of 1.5.
B. Development Criteria Reference and Constraints
1. The 10 year flow rates were used for the design of drainage swales and
culverts. The retention pond was sized for 1.5 times the 24 hour 100 year
storm event.
C. Hydrological Criteria
1. Intensity Duration Frequency(IDF) curves for the City of Greeley were
used for this report.
2. The 100 year storm value was calculated using the FFA method for the 24
time period with an inflow volume of 68114 CF. Copies of the output are
attached in Appendix A. An imperviousness value of 43 percent, type "B"
soils and an area of 6.24 AC was entered into the program. A factor of
safety of 1.5 is then applied to the 24 hour volume and produces a
retention volume of 102,177 CF per 24 hour period, see appendix A. The
retention pond has a volume of 118,012 CF. The WQCV for this site was
calculated to be 4,669 CF. The pond has a bottom elevation of 4,727.0, a
100 year water surface of 4,732.6, and a weir elevation of 4,732.6. This
method has been used in the past to determine the Retention Volume for
other project designed, by this office, in Weld County and is outline in the
Urban Storm Drainage criteria Manual, Volume 2, page SO-12.
D. Hydraulic Criteria
I. The Retention Pond calculations are discussed above in this report.
2. There is no outlet structure for the Retention pond as there is no outlet
flow. Flows above the 100 year storm will crest the retention pond and
pond along the west side of WCR 27.
IV. Drainage Facility Design
A. General Proposed Concepts
I. The 10 year storm event will be routed thru the site using overland
flow, swale sections and culverts to the proposed retention pond in
the southeast corner of the site.
B. Specific Details
1. The drainage problem encountered in the conceptual design of the
drainage plan for this site is the lack of culverts downstream of the
5
project site and the site elevation as compared to the surrounding
area. The proposed solution is the use of retention instead of
detention, see item 1 above.
2. The site will have a fence along the property lines so the proposed
retention pond will be enclosed. Maintenance access would occur
on the south side of the retention pond from the site drives. The
side slope used in the design of the retention pond is 3:1, this slope
is the maximum permitted by Weld County in storm water pond
design.
3. The site is has one basin that drains to the proposed retention pond.
Some of the site will drain to the borrow ditch along WCR 27 and
pond along the road below the retention pond.
4. The retention pond has a 15.0 foot overflow structure that is sized
to handle the 100 year flow from the site.
5. The proposed storm water system will be easily maintained as it is
a retention pond site sheet flows. The drainage swales have side
slopes of 3:1 and greater. The proposed retention pond has design
slopes of 3:1.
6. The Maintenance Plan will consist of seeding all landscaped areas
and the retention pond with native grasses. The native grasses will
be mowed and kept shorter than 12"per Weld County Code.
Sedimentation is to be removed from the retention pond as needed.
After the site has stabilized, the retention pond should be cleaned
of accumulated sediment. The proposed drainage swales and
retention pond shall be inspected after major storms and
damage/erosion damage shall be repaired in a timely manner to
minimize further damage.
V. Conclusions
A. Compliance with the Weld County Code.
1. The storm water system design is compliant with the Weld
County Code for storm water system design.
B. Drainage Concept
1. The effectiveness of the drainage design in routing drainage
flows by means of sheet flow to the retention pond. The
retention pond will control flooding on the site and to the
adjacent downstream property located to the south and east
during the 100 year storm event. The retention pond will detain
in excess of the 100 year flow volumes flood downstream of the
site.
2. Riprap is to be installed on the retention pond overflow structure.
3. References
a. Urban Storm Drainage Criteria Manual, Volume I,
II, III. Revise April 2008.
b. Weld County Addendum to the Urban Storm
Drainage Criteria Manual, October 2006.
6
c. Urban Storm Drainage Web Site for Spreadsheet
Models.
d. City of Greeley Storm Drainage Manual Vol. II,
March 2007.
e. Civil Engineering Reference Manual, Lindeburg
Eleventh Edition.
f. Colorado Department of Public Health and
Environment, SWMP Permit.
g. USDA Natural Resource Conservation Service,
Web Soil Survey, National Cooperative Soil
Survey, Accessed May 20145.
h. Weld County Engineering and Construction
Criteria, April 2012, Draft Copy.
7
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Custom Soil Resource Report
Map Unit Legend
Weld County,Colorado,Southern Part(CO618)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOl
32 Kim loam,1 to 3 percent slopes 10.8 75.1%
46 Olney fine sandy loam,0 to 1 3.6 24.9%
percent slopes
Totals for Area of Interest 14.4 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the soils
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas.A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils.On the landscape,
however,the soils are natural phenomena, and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class.Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
classes.Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management.These are called contrasting,or dissimilar,components.They generally
are in small areas and could not be mapped separately because of the scale used.
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each.A few areas of minor components may not have been
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
have similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
10
Custom Soil Resource Report
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer,all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example, Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas.Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform. An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them.Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
11
Custom Soil Resource Report
Weld County, Colorado, Southern Part
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
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed eolian deposits derived from sedimentary rock
Typical profile
H1 -0 to 12 inches: moderately alkaline, loam
H2- 12 to 40 inches: moderately alkaline, loam
H3-40 to 60 inches: moderately alkaline, fine sandy loam
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural 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 in profile: 15 percent
Available water storage in profile: Moderate(about 9.0 inches)
Interpretive groups
Farmland classification: Prime farmland if irrigated
Land capability classification (irrigated): 3e
Land capability classification (noninigated): 4e
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067BY002CO)
Minor Components
Otero
Percent of map unit: 10 percent
12
Custom Soil Resource Report
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
Typical profile
H1 -0 to 10 inches: neutral, fine sandy loam
H2- 10 to 20 inches: neutral, sandy clay loam
H3-20 to 25 inches: moderately alkaline, sandy clay loam
H4- 25 to 60 inches: strongly alkaline, fine sandy loam
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
Natural 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 in profile: 15 percent
Salinity, maximum in profile: Nonsaline(0.0 to 2.0 mmhos/cm)
Available water storage in profile: Moderate (about 7.0 inches)
Interpretive groups
Farmland classification: Prime farmland if irrigated and the product of I (soil
erodibility) x C (climate factor)does not exceed 60
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 4c
Hydrologic Soil Group: B
Ecological site: Sandy Plains (R067BY024CO)
13
Custom Soil Resource Report
Minor Components
Zigweid
Percent of map unit: 8 percent
Vona
Percent of map unit: 7 percent
14
Appendix A
Percent Imperviousness Existing
Site Area = 271630 ft2 Percent Imperviousness from Table RO-3
Paved 1.00
Existing Site Conditions Gravel 0.40
Paved 0 ft` Roofs/Concrete 0.90
Packed Gravel 0 ft2 Greenbelts/Landscaping 0.02
Roofs/Conc 0 ft2
Landscaping/Undev. 271630 ft2 = 6.24 AC
Percent Imperviousness Existing = 0.02 = I
Time of Concentration tc Historic
L = 657 ft C5 = 0.09 Table RO-5
Delta = 8 ft
S = 0.0122 ft/ft
t;_ (0.395'(1.1-05)*Lo5)/So.33 (Min.) Eq. RO-3
t;= 43.80 min.
or
V=Q *Sw0.5 (ft/sec) EQ. RO-4
From Table RO -2 C = 5
V= 0.5517 ft/sec
t.= LN = 1190.8 sec = 19.85 Min.
Use 19.85 Min. for t;Historic
Historic Release Rate per AC = O10 = C10110
or
Historic Release Rate = O10 = C,ol,pa
C10 = 0.17
I10 = 3.5
a= 6.24
O10 = C10110= 0.60 CFS/AC
or
O10 = C10l1oa= 3.71 CFS
Percent Imperviousness Total Developed Area
Site Area = 271630 ft2 = 6.24 AC
Paved 8700 ft2 Paved 1.00
Recycled Asphalt 168082 ft` Recycled Asphalt 0.45
Roofs/Conc 32050 ft2 Roofs/Concrete 0.90
Landscaping/open S 62798 ft2 Greenbelts/Landscaping 0.02
Percent Imperviousness Proposed = 0.42 = I
From Modified FFA Methoud Spreadsheet Detention Volume = 68118 CF
Retention pond =68118.0 * 1.5 = 102177 CF
Water Quality Capture Volume(WQCV)
WQCV=a(0.91i3-1.19i2+0.78i) Page SQ-24
for 40 hr Release a = 1
Required Storage =(WQCV/12)'Area Page SQ-24
Area = 271630 ft` = 6.24 AC
Required WQCV Storage = 0.107 AC-ft = 4669 ft3
Total Required Volume 102177 ft3= 2.35 AC-FT
Ponding Depth = 31.6-27.0 ft
4.6 FT
Weir Calculations Retention Pond
Emergency Over-Flow Weir Calculations
Q = 14.98 CFS
Using Broad-Crested-Weir Equation
Q = CLH15 with C =3.1
L = 15.00 ft
H = 0.5 ft
Q = 16.44 CFS >= 14.98 CFS
Riprap Calculations
From Page HS-67 V=Q/A
A = L*H = 7.500 ft2
V= 2.192031 ft/sec
From Eq. HS-16 Pd= (V2+ gc91/2 d=H= 0.5 ft
g = 32.2 ft/sec2
Pd = 4.57
From Figure HS-20 Use Type L Riprap
From Eq. HS-17 T= 1.75*D50 D50 = 9 in.
T = 15.75 in.
From Figure MD-22 Use Type "L" Riprap
Appendix A
Pond Volume Calculations
Average Area Method =((Al +A2)/2)* Stage Depth = Stage Volume(CF)
Elevation Contour Area
(NAVD 29) Volume of Acculative
( ) Stage(ft3) Volume(f13) Required Detention
4732.6 26787.29 15677.9 118012.0 equals 102177 CF
4732.0 25472.45 46798.9 102334.0 11-
volume @
4730.0 21326.45 38869.8 55535.1
4728.0 17543.34 16665.4 16665.4 4732.0 = 102334 CF
4727.0 15787.36 0.0
DETENTION VOLUME BY THE MODIFIED FAA METHOD
(See USDCM Volume 2 Storage Chapter for description of method)
Project: Varra Construction -
Basin ID: Lots A&B Detention Pond
(For catchments loss than 160 acres only. For larger catchments.use hydrograph routing method)
(NOTE:for catchment:larger than 50 acres,CUHP hydrograph and routing em recommended)
Determination of MINOR Detention Volume Using Modified FAA Method Determination of MAJOR Detention Volume Using Modified FM Method
Design Information pnputl: Deslon Information(Input):
Catchment Drainagelmperwnusnese I,= 4200 percent Catchment Drainage Impervloucnea I,= 42.00 ril
arte CatcAre CatchmenPted 00n10enlfl0 SS q= B,Sap feedee lepesnl0 050 o= 0.240
acorn
Return Period
MRCS Group Type= 9 ACOs me:D Retur Pedod fl N Rtetion Group Typo= a 7101*C2 ere
RmeoPcncntr Detention tiosrlWaternherol T^ 1. yearminutes.5,10.25,50,111001 Rlimern ePonoeeeieten elanpeol c= 1 I yeere(2.5.10.55.50,or 1007
Allmoel Ce nil Release
o lVlatereM1atl ic= dB/acre
Amealeen eleas of VlalereM1eE Tc= 14.4 _mehicre
Ono-houAllowablr UPr it Reetunr Pale ,= 1.20 541141 Allowable e-o Unit Pc Meador Pale q= 1.20 ironer*
Ono-hour Raleleill SFc F Pr= 1.81 rnchee Dee-hour lalPon P,= 2)0 ironer
Design Mtl nlallmF Formula 1=C.P,IICaeT,1"C, Coefcnt Ono mF Fermule 1=c.P11(CraT,l Cr
Coefficient TOnewo C,0 2850 Coefficient Two Cie 200
oeeNuat Two C 00 to Coefficient Two Cie 10
coelndal Three F= 0.100 Coeflid.m cure cr= 0.7B0
b mil ion of Av r eOutflow fr m h a In I I d: Determinetlon of Average Outflow from the Basin ICelculetedli
Runoff Coefficient co 011) Runoff Coefficient Ce 0.50
Inflow Peak Runoff Cede= 0.51 __da InIlmv Peak Runoff Op-In=_ f0_05__de
Allowable Peak Outflow Rale Opoul a 7.4e ale Allowable Peak Outflow Pale Opuu1= 7.49 4 cfe
Mod FAA Miner Storage Volume= 400 cubic feet Mod.FAA Majoreloreee Volume 14,435 _4.cubic feet
Mod.FAA Weer Storage Velum*= 0_000_ _ cre-11 Mod.FAA Moron Storage Volume= _ 0.]]1 mcsa.fr
30 u_Enter Rainfall Duration Incremental bereave Value Hoe to 0 6ter SMleuleel
Rainfall Reinlell Inflow Adieeoeenl Average Outflow Storage Rainfall Rolnlell meow Adjueienl Average Outflow Storaie
Duration Intently Volume Factor Outflow Volume Volume Duration Internally Volume Factor Outflow Volume Volume
mmutee inches/lir cubic feel de cubic feel cubic feel minute, bmecihr outdo feel no abic leer cubic feel
Ilorun (oeye0 (cutout) laaml loulup (4490.0 14410011 Frpull loorpull (smote) 100040 toepull (output) 10,10011
0 0po a 1 000 I 400 10 0 0.00 0 m rips a a __
Jo 2.00 1030] 00 535 0903 400 30 4.31 24227. ` 0]d L 555 0122 I 14204
1.01 uu] 2 484 10,)22 ]]c0 e0 27) 21153 0.02 aes 14)22 I 14au—
ppL
G0 121 15110 050 J 4]4 23.4B1 0946 v0 lie 25.173 one4]0 22,481 11811
120 Ono 1 307 0s 019 20201 12014 120 1?0_ J0 z]0 0 fi I
I ale 30.201 9,020
150 043_ 1]308 ass 4.10 ]eva0 1 560 150 44 40020 055 457 28940 1833
_00 1] 10220 Cs 4.ce 1 42057 zs 450 le iZB1 zfia fi I' 4.04 1 <aem 1105'
210 oa5 _ 1.030 052 4,00 1 50,410 -31.464 30 1.12 I 44,102 052 4.00 J. 50410 -0 I 230_
240 L 050 10502 002 307 1 57.15] 2]504 240 1.02 I 45.041 I 0.53 10) 57,15] I 11,500
272 I 1154 20.120 OS] 3.04 0],40) 43,770 270 002 I 46.903 003 3.04 03,007 .1 0,934
=
3.02 300 1 000 — 20.0]] 052 I. j ]08]11 .40 000 0 0_00 48,159 0 52 3.02 ]0,0]0 2
3 040 21,105 52 I J01 ]].]]5 512]0 330 0.90 40,240 052 3,01 ]],275 28,120..121
300 ) 0.45 216]8 JI 053 I 3.00 1 04.114 -025]0 300 0.]5 I 60,550 i 052 I ]BD 04,114 32,050
30 I 041 11,041 02 I Sea 00,05] -0001] 20 O70 I 51180 052 1 300 00053 ( ]0050
420 I m30 22,]10 I 052 2.07 I 01,50] 20 000 520)0 I 0.02 3 0 0]_503 I -45,517
450 030 23000 053 ].e8 I 11.071 -011000 050 45 0.00 02007 052 3_00 111,0]1 0
514 _
010 015 23,000 53 B.9 111.071 -0048] nea 0.00 1 54430 052 ]00 111,011 0]300
540 1 032 2]03] DM I 3.B4 117.010 T- .94.484510 one 06] I 54.430 I 051 -01300
540 I 020 2]0]0 0 1 104 134500 107,320 572 I 016I 55012 I 051 304 121.200 -0147
600 020 2]100 051 I ].Ca 12,090 11]032 010 092 j 5502 a5 3 04202 131,010 050]0
030 020 24,105 051 03 144707 I 12]800 030 r 040 57077I 051 ].83 144,707 0110
000 037 24711 05 1.I 3 0 1 50] ..120.000 030 47 5757] 01 ]02 144.707 0]40
000 2] 24.715 001 I ].0] I 1515 130200 000 047 57,572 } OC 3.09 00240 B]ON
� 300
720 124 20103 0.01 I BZ 150205 2]700 2 I 044 50700 I 051 �. 52 104,e00 I -100_
720 025 25110 05 I 102 104.905 p79B )30 094 54]11 it 051 202 11,745 02180
750 m3a 25425 05 ]B2 1]1.]34 140,219 )50 002 0822] 1 0 5 I ].02 1]_]24 113]01
700 024 25040 151 ! aa1 179403 152e14 ]80 Lai i 50050 I D51 3.01 170,40] •110,013
010 .23 25,004 0.51 3 01 105,202 .151330 010 0.40 I ,351 0.51 181 115.202 .124,852
0. 1 1B1 101,041 I 0070 10 021 25012 J _051 ,4 ],81 f 100 91 1]2470 0)0 030 I 01308 _ 051 ]611 1100021 81 I 13]352
2
000 022 l 20471 051
021 _ 2 401 51 3.011 215150 105407 000 0.3) 1 8 ]B] 051
030 021 30162 51 200 212,150 I 102000 030 p,]0 0221] _ ,150 141.119
000 0,22 30740 05 100 210809 102050_ _ 00cia0 Los_ 0]0]1 051 I 2.00 SZ'a1B 150)51
02.000
101 0.50 2)0]0 051 200 226,037 100 100 0.34 I 42800 051 2'0 2180]7 j 102,570
1010 0 2,20) 0.51 180 i 23297 208170 1020 0A] 1 01484 051 I 1011 232,377 j 109002
0 1050 0 10 i 27,240 00 ],90 238110 F 211734 000 0]3 01208 I 051 100 220,110 01012
1070 0.18 27,500 051 ].70 249055I 210]00 1D10 0.21 04,202 051 270 24;055i 101.510
1000 0.10 27,]14 05 2 7 255504 .21W000 1110 0.22 0400] r 001 37 I 252004 0],027
ma le 2]075 0fi 3 7 250]]3 2]1,452 1140 II 52 55011 051 , 3.10 250]33 04,200
11]0 all 200]0 0 5i 1)0 200.0]] I 2]0,0]0 11]0 021 I 0571] a 51 3.]0 2000]] 200050
lzoo On 20,100 Osl a.]o 272.012 r .244,023 1200 ..— .—_0.20 1 05775 51 170 172,012 ( 07,Om
12]0 I 0 1 20]40 I 0.01 330310 378,551 25 211 1220 020 0E130 I 051 3.70 2]0,551 21].422
1200 010 21420 051 1]0 265.200 25)001 1200 0.30 41470 051 3.70 200.200 210,014
1280 20.035 051 270 211020 1_ 204304 1200 026 00017 1 _ 051 3.)0_ -I
010202.V21 1 2!!,219
1220 015 20010 051 ]70 200500 4 271,000 1330 02] 1 07,451 1 051 270 200]00 1 _2]2_020
1351 015 20017 0 370 3705_0 1 2]]100 1300 02) 01,0)1 I 051 237 11,540 240,040
1410 015 2005] 2]B ]13.207 t 1B4,100 1300 029 0].001 01 1]7 j ]120) 305.470
1410 015 20,103 r 051 3.70 ]10180 200,004 1410 I 020 54110 0.51 I 170 I ]10.020 i _251,051
1400 015 20]!1 151 3 ]20125 217300 1440 024 0421 r 051 I 3 7 ]x8,125 4 250,!57
14]0 014 F 20.45] 050 ]]0 3]405 1 ]04008 1470 020 r 007]5 I 150 I 3.]0 3].405 204]]0
1520 010 1 20,000 061 118 340,204 -i10,010 1500 025 r 50.030 I 0.50 I 326 340,204 271,100
1520 114 21)13 050 274 341.043 r .31],230 15]0 0.24 07.322 0.50 I 2 7]40,04] 277,011
1500 1.14 20.5211 050 2 70 I 153.002 ]21044 1500 I 0.24 00,623 050 1 2 1351002 1 284,000
75'40 014 10000 0 5 270 340421 3t 01 1500 I 0 20,010 0:0 ].70 I ]00421 •Z 511
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1050 013 30.201 I 050 770 372000 21000 IPSO 0.23 70477 I 050 310 371000 201410
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1710 0 1i ]0425 650 ]70 357,170 15704] 1712 017 7143i7 I 050 3 70 257]]0 .90392
1740 0,13 =2540 050 I ]is 204117 ]02509 11 0 i 0.22 79,2113 0.50 1100 I 304,117 211524
1770 013 30052 050 377 400,057 270,105 1770 I 032 71040 050 211 I 400,057 -]20,310
1
1500 i 012 30,71] 0 52 ]77 40].543 I -90023 1000 I p.21 71,810 i 055 I 3.77 I 4Di050 . .]35,700
Mod.FAA Minor S1ore0*Volume(cubic ILl= 400 Mod.FAA Major Storage Velum.rouble 110= 14,435
Mod.FAA M[nor Storage Volu malacre.lt1= 00002 Mod,FAA Meier 01wa0*Volum*lacre-Ill= 02111
UDFCD DETENTION VOLUME ESTIMATING WORKBOOK Version 2.2.Released January 201(1
"FA Donohoe foal 2015 050 i'eumlaery,700,1{,O4 FAA 0112121114,144 PM
DETENTION VOLUME BY THE MODIFIED FAA METHOD
(See USDCM Volume 2 Storage Chapter or description of method)
Project: Varra Construction
Basin ID: Lots A&B Detention Pond
Inflow and Outflow Volumes vs.Rainfall Duration
500,000
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UDFCO DETENTION VOLUME ESTIMATING WORKBOOK Version 22.2.Released January 2010
=4/4 Ctlnn Wu Finn 2014.000 Cm, me]FAA 04212014 4 m PM
Final Drainage Report
Reststop Storage
Scott McBride, Owner
31555 WCR 27.
Greeley, CO
June 11, 2014
"I hereby certify that this report for the final drainage design of Reststop Storage was
prepared by me (or under my direct supervision) in accordance with the provisions of the
Weld County storm drainage criteria for the owners thereof."
Mark A. Taylor
Registered Professional Engineer
State of Colorado No. 46065
1
Table of Contents
1. General Location 3
A. Location 3
B. Description of Property 3
II. Drainage Basins and Sub-basins 3
A. Major Basin Description 3
B. Sub-Basin Description 4
III. Drainage Design Criteria 4
A. Regulations 4
B. Development Criteria References and Constraints 5
C. Hydrological Criteria 5
D. Hydraulic Criteria 5
IV. Drainage Facility Design 5
A. General Concept 5
B. Specific Details 5
V. Conclusions 6
A. Compliance with the Weld County CODE 6
B. Drainage Concepts 6
Appendix A
Table of Contents
Page Data
1 — 1 Vicinity Map
1 - 7 Site Soil Survey Data
1 —6 Rational Method and Retention Pond calculations
1. General Location
A. Location
I. The Final Plan Drainage Report is for a parcel located in part of the
North half of Section 30, Township 6 North, Range 66 West of the 6th
P.M.
2. Weld County Road 27 is located along the eastern side of the parcel.
Railroad ROW is located to the southwest of the parcel and just north
of WCR 64 %z. The access to the site is by the use WCR 27. This
railroad crossing may possibly be closed by Weld County at a future
date. This grading plan accounts for the future road configuration.
3. There are no major open channels, lakes, or irrigation facilities within
or adjacent to the proposed development. The proposed changes do not
adversely affect the site.
4. The areas to the west, north and east are undeveloped and are areas
that are farmed. WCR 27 is located just to the east of the site. There
is a railroad ROW just to the south of the parcel.
B. Description of Property
1. The area covered in this drainage report is approximately 6.24 acres.
2. The existing ground cover, on the site is sparse as the site was tilled
and is presently fallow. Some low weeds do exist on the development
site. The site has two soil types, Kim loam and Onley fine sand loam,
and both are type B (Hydrologic soil type).
3. There are no major open channels on or adjacent to the site.
4. The proposed site development would consist approximately 285
storage stalls for recreation vehicle, a caretaker unit, RV dump site and
a retention pond. Recycled asphalt will be used for the drive surfaces
of the development. The proposed road center lines will generally
follow the existing ground elevations and will follow the existing
natural flow patterns from the northwest to the southeast. Storm water
facilities for the site will be retention pond which is located at the low
point of the site near WCR 27.
5. There are no irrigation facilities on this site. Local concrete irrigation
ditch on adjacent property to the north and west of site.
6. The ground water table is assumed to be just below the surface as
moist to saturated soils are present in the low area of the site near
WCR 27.
Il. Drainage Basins and Sub-Basins
A. Major Basin Description
1. Weld County Public Works was contacted in regards to existing
drainage reports and Master Drainage plans in the area. No
information was available. The site is within the "North Greeley Rail
Corridor Subarea Plan" and there are no drainage studies referenced in
the plan.
3
2. The site is located in the Cache La Poudre River basin. The site is
approximately %2 mile north of the floodplain on Community Panel
080266 0608 C.
3. There are no irrigation facilities on this site. Local concrete irrigation
ditch is located on western and northern sides of the site.
4. The drainage plan has 2 foot existing and proposed contours for the
proposed development and retention pond area.
B. Sub-Basin Description
1. The historic drainage pattern of the site is as follows. In general
Stormwater flows at this site flow to the Southeast at 1.0 to 1.5%
grades. At this time there is no culvert under WCR 27 at the low point
of the site and there is nowhere for storm water flows to drain, so a
retention pond was used to detain storm flows on the site.
2. Topographic data has been obtained for the project to a minimum of
50 feet beyond the limits of the subdivision. Topographic data, to the
east, was obtained out to include WCR 27. Offsite storm water flows
from the north are routed around the site by a irrigation ditch on the
parcel to the north and west of this site. Off-Site drainage from the
north and west has little to no impact during most storm events.
III. Drainage Design Criteria
A. Regulations
1. The 10 and 100 year storm events were used to design and develop
the drainage system for this development per the Weld County
regulations.
2. There are no existing master drainage studies or plans for the area.
The site is surrounded by irrigated farming to the north and west
that would have minimal flows on to this site. To the east is WCR
27 and to the south of the site is Colorado and Southern Railroad
ROW and tracks.
3. The proposed drainage pattern will be as follows: the site will
generally have sheet flow and small swale flows to the retention
pond located at the low point of the site just west of WCR 27.
4. No request for variances is being requested; however the choice of
retention over detention will be discussed in this section. The
owner and developer have requested the use of retention pond for
storm water facilities for this site. Detention was examined and the
site has no historic release for drainage flows. There are no
culverts under WCR 27 or the Railroad ROW and the property to
the south and east of the site are higher than this site. With no
release for a detention pond the use of a retention pond is a viable
solution. The site soils, by a site open hole inspection, are very
well drained, sandy loam. The assumed percolation rate at the site
is assumed to be approximately 15 min. /in. Using 15 min. /in. and
4
a ponding depth of 5.65 feet, the retention pond would drain in
16.8 hours. The use of the retention pond would likely have an
effect on the local water table during large storm events, the effects
would be short term. The existing ground water elevation is
assumed to be approximately 2 feet below the existing ground
elevation and this value was obtained from the property owner. A
benefit of using a retention pond is there will be no impact on the
drainage system downstream of the site. During the 100 year
storm event, flood waters may flow into the proposed retention
pond, as it is over sized by a safety factor of 1.5.
B. Development Criteria Reference and Constraints
1. The 10 year flow rates were used for the design of drainage swales and
culverts. The retention pond was sized for 1.5 times the 24 hour 100 year
storm event.
C. Hydrological Criteria
1. Intensity Duration Frequency (IDF) curves for the City of Greeley were
used for this report.
2. The 100 year storm value was calculated using the FFA method for the 24
time period with an inflow volume of 68114 CF. Copies of the output are
attached in Appendix A. An imperviousness value of 43 percent, type "B"
soils and an area of 6.24 AC was entered into the program. A factor of
safety of 1.5 is then applied to the 24 hour volume and produces a
retention volume of 102,177 CF per 24 hour period, see appendix A. The
retention pond has a volume of 118,012 CF. The WQCV for this site was
calculated to be 4,669 CF. The pond has a bottom elevation of 4,727.0, a
100 year water surface of 4,732.6, and a weir elevation of 4,732.6. This
method has been used in the past to determine the Retention Volume for
other project designed, by this office, in Weld County and is outline in the
Urban Storm Drainage criteria Manual, Volume 2, page SO-12.
D. Hydraulic Criteria
1. The Retention Pond calculations are discussed above in this report.
2. There is no outlet structure for the Retention pond as there is no outlet
flow. Flows above the 100 year storm will crest the retention pond and
pond along the west side of WCR 27.
IV. Drainage Facility Design
A. General Proposed Concepts
1. The 10 year storm event will be routed thru the site using overland
flow, swale sections and culverts to the proposed retention pond in
the southeast corner of the site.
B. Specific Details
1. The drainage problem encountered in the conceptual design of the
drainage plan for this site is the lack of culverts downstream of the
5
project site and the site elevation as compared to the surrounding
area. The proposed solution is the use of retention instead of
detention, see item 1 above.
2. The site will have a fence along the property lines so the proposed
retention pond will be enclosed. Maintenance access would occur
on the south side of the retention pond from the site drives. The
side slope used in the design of the retention pond is 3:1, this slope
is the maximum permitted by Weld County in storm water pond
design.
3. The site is has one basin that drains to the proposed retention pond.
Some of the site will drain to the borrow ditch along WCR 27 and
pond along the road below the retention pond.
4. The retention pond has a 15.0 foot overflow structure that is sized
to handle the 100 year flow from the site.
5. The proposed storm water system will be easily maintained as it is
a retention pond site sheet flows. The drainage swales have side
slopes of 3:1 and greater. The proposed retention pond has design
slopes of 3:1.
6. The Maintenance Plan will consist of seeding all landscaped areas
and the retention pond with native grasses. The native grasses will
be mowed and kept shorter than 12"per Weld County Code.
Sedimentation is to be removed from the retention pond as needed.
After the site has stabilized, the retention pond should be cleaned
of accumulated sediment. The proposed drainage swales and
retention pond shall be inspected after major storms and
damage/erosion damage shall be repaired in a timely manner to
minimize further damage.
V. Conclusions
A. Compliance with the Weld County Code.
1. The storm water system design is compliant with the Weld
County Code for storm water system design.
B. Drainage Concept
1. The effectiveness of the drainage design in routing drainage
flows by means of sheet flow to the retention pond. The
retention pond will control flooding on the site and to the
adjacent downstream property located to the south and east
during the 100 year storm event. The retention pond will detain
in excess of the 100 year flow volumes flood downstream of the
site.
2. Riprap is to be installed on the retention pond overflow structure.
3. References
a. Urban Storm Drainage Criteria Manual, Volume I,
II, III. Revise April 2008.
b. Weld County Addendum to the Urban Storm
Drainage Criteria Manual, October 2006.
6
c. Urban Storm Drainage Web Site for Spreadsheet
Models.
d. City of Greeley Storm Drainage Manual Vol. II,
March 2007.
e. Civil Engineering Reference Manual, Lindeburg
Eleventh Edition.
f Colorado Department of Public Health and
Environment, SWMP Permit.
g. USDA Natural Resource Conservation Service,
Web Soil Survey, National Cooperative Soil
Survey, Accessed May 20145.
h. Weld County Engineering and Construction
Criteria, April 2012, Draft Copy.
7
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Custom Soil Resource Report
Map Unit Legend
Weld County,Colorado,Southern Part(CO618)
Map Unit Symbol Map Unit Name Acres In AOI Percent of AOI
32 Kim loam, 1 to 3 percent slopes 10.8 75.1%
46 Olney fine sandy loam,0 to 1 3,6 24.9%
percent slopes
Totals for Area of Interest 14.4 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the soils
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas.A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils.On the landscape,
however,the soils are natural phenomena,and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class.Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
classes. Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management.These are called contrasting,or dissimilar,components.They generally
are in small areas and could not be mapped separately because of the scale used.
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each.A few areas of minor components may not have been
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
have similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
10
Custom Soil Resource Report
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example,Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas.Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar.Alpha-
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management.The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform.An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them.Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
11
Custom Soil Resource Report
Weld County, Colorado, Southern Part
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
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed eolian deposits derived from sedimentary rock
Typical profile
H1 -0 to 12 inches: moderately alkaline, loam
H2- 12 to 40 inches: moderately alkaline, loam
H3-40 to 60 inches: moderately alkaline, fine sandy loam
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural 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 in profile: 15 percent
Available water storage in profile: Moderate (about 9.0 inches)
Interpretive groups
Farmland classification: Prime farmland if irrigated
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067BY002CO)
Minor Components
Otero
Percent of map unit: 10 percent
12
Custom Soil Resource Report
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
Typical profile
H1 -0 to 10 inches: neutral, fine sandy loam
H2- 10 to 20 inches: neutral, sandy clay loam
H3-20 to 25 inches: moderately alkaline, sandy clay loam
1-14-25 to 60 inches: strongly alkaline, fine sandy loam
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
Natural 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 in profile: 15 percent
Salinity, maximum in profile: Nonsaline(0.0 to 2.0 mmhos/cm)
Available water storage in profile: Moderate (about 7.0 inches)
Interpretive groups
Farmland classification: Prime farmland if irrigated and the product of I (soil
erodibility) x C (climate factor)does not exceed 60
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 4c
Hydrologic Soil Group: B
Ecological site: Sandy Plains (R067BY024CO)
13
Custom Soil Resource Report
Minor Components
Zigweid
Percent of map unit: 8 percent
Vona
Percent of map unit: 7 percent
14
Appendix A
Percent Imperviousness Existing
Site Area = 271630 ft2 Percent Imperviousness from Table RO-3
Paved 1.00
Existing Site Conditions Gravel 0.40
Paved 0 ft` Roofs/Concrete 0.90
Packed Gravel 0 ft2 Greenbelts/Landscaping 0.02
Roofs/Conc 0 ft2
Landscaping/Undev. 271630 ft` = 6.24 AC
Percent Imperviousness Existing = 0.02 = I
Time of Concentration tc Historic
L = 657 ft C5 = 0.09 Table RO-5
Delta = 8 ft
S = 0.0122 ft/ft
= (0.395'(1.1-05)*L°'5)/S°.33 (Min.) Eq. RO-3
t1= 43.80 min.
or
V= C„* S„,°'5 (ft/sec) EQ. RO-4
From Table RO -2 C„= 5
V= 0.5517 ft/sec
t1= L/V = 1190.8 sec = 19.85 Min.
Use 19.85 Min.fort;Historic
Historic Release Rate per AC = Q10= O10110
or
Historic Release Rate = Q10 = C10110a
O10 = 0.17
110 = 3.5
a= 6.24
O10 = O10110= 0.60 CFS/AC
or
O10 = C10110a= 3.71 CFS
Percent Imperviousness Total Developed Area
Site Area = 271630 ft2 = 6.24 AC
Paved 8700 ft2 Paved 1.00
Recycled Asphalt 168082 ft` Recycled Asphalt 0.45
Roofs/Conc 32050 ft2 Roofs/Concrete 0.90
Landscaping/open S 62798 ft2 Greenbelts/Landscaping 0.02
Percent Imperviousness Proposed = 0.42 = I
From Modified FFA Methoud Spreadsheet Detention Volume= 68118 CF
Retention pond = 68118.0 * 1.5= 102177 CF
Water Quality Capture Volume(WQCV)
WQCV=a(0.91i3-1.19i2+0.781) Page SQ-24
for 40 hr Release a = 1
Required Storage =(WQCV/12)*Area Page SQ-24
Area = 271630 ft` = 6.24 AC
Required WQCV Storage = 0.107 AC-ft = 4669 ft3
Total Required Volume 102177 ft3= 2.35 AC-FT
Ponding Depth = 31.6-27.0 ft
4.6 FT
Weir Calculations Retention Pond
Emergency Over-Flow Weir Calculations
Q = 14.98 CFS
Using Broad-Crested-Weir Equation
Q = CLH''5 with C = 3.1
L = 15.00 ft
H = 0.5 ft
Q = 16.44 CFS >= 14.98 CFS
Riprap Calculations
From Page HS-67 V= Q/A
A = L*H = 7.500 ft2
V= 2.192031 ft/sec
From Eq. HS-16 Pd =(V2+gd)1/2 d=H= 0.5 ft
g = 32.2 ft/sec2
Pd = 4.57
From Figure HS-20 Use Type L Riprap
From Eq. HS-17 T = 1.75`D50 D50 = 9 in.
T = 15.75 in.
From Figure MD-22 Use Type "L" Riprap
Appendix A
Pond Volume Calculations
Average Area Method =((Al +A2)/2) * Stage Depth = Stage Volume(CF)
Elevation Contour Area
(NAVD 29) Volume of Acculative
(ft2) Stage(ft3) Volume(ft3) Required Detention
4732.6 26787.29 15677.9 118012.0 equals 102177 CF
4732.0 25472.45 46798.9 102334.0 volume @
4730.0 21326.45 38869.8 55535.1 4732.0 = 102334 CF
4728.0 17543.34 16665.4 16665.4
4727.0 15787.36 0.0
DETENTION VOLUME BY THE MODIFIED FAA METHOD
(See USOCM Volume 2 Storage Chapter for description of method)
Project: Varra Construction
Uusin ID: Lots A&B Detention Pond
(For catchments less than 160 acres only. For larger catchments,use hydrogreph routing method)
(NOTE.for catchments larger than 90 acres,CUHP hydrograph and routing fro recommended)
Determination of MINOR Detention Volume Using Modified FAA Method Determination of MAJOR Detention Volume Using Modified FAA Method
pesl0n Information 11nou11: Doslan fnformnllon llnoutt:
Cachment Drainage Imperriaueneua I,•_ 42.00 pe,cme Ca uhm.nt Dnlneae Impe,vlouenese I,, 42.00 pe,eenl
Cakhreenl Drainage Are. A= 6.340 Pore. Catchment Dealnage Are. A• 8.240 aces
Predevolopment NRCS Soil Group Typo= ft A,B.C.of 0 Predevalopmenl NRCS Soil Group Typo• a A.0,C.or 0
Return Period k r Detention CcnEcl T a 10 years 12.6 10.25,50,or 100) Retain Pariad for Detention Control T=j . 100 1y.ere I2,0.10,26.60 or 107i
Timis of Concentration at Watershed 7e= 14 a minute Time of Cancene.tion at Watershed To• 14.4 minute.
Allowstde Unit Rele.e Rate 0= 5.20 cfel.ere Allswablo Unit Relooce Rote q•, 1.20_ cfebacre
One-hoer Precmiktion P,_ '.6 inches One-hour Precipilstien P,• 270 Inches
Design Rainfall IDF Formula to C,'P„/(CeT,I•0, Da.lon Rainfall IDF Form uts In C,'P,I(c,.T,)•C,
Coefficient One C,= 20 50 Coefficient One O.• 2850
Coefebnl Two Co= 10 Coefficient Two Co• 10
Coefficient Three C,= 0.709 Coefficient Thee C,•`0.740
DoterminatIOn of AverpQe Outflow from th IC e Basin elculatod{: De4onnlnatlon of Average Outflow from the Basin fCalculate&}&
Runoff Coefficient c a_ 0.37 Runoff Coefficient C a 0.50
Inflow Peak Runoff Qp•In= 0.51__cf. Inflow Peak Runoff Qp-In= 10.86— de
Allowable Peak Mellow Rote Qp-out•, 40_7, , _ecf. Allowable Peak Outflow Rsb 0p'cut a 7_40 __de
Mod.FAA Minor Storage Volume• 400 _.wile fell Mod.FAA Major Storage Volume a 14.435_ euhle feel
Mod FAA Minor Storage Volume o 4000 J .efa41 Mod.FAA Hafer Storage Volume=__ 0331 re-ft
30 4-Enter Rainfall Duration Incremental Increase Value lief.foe 0 lore—W..1,0
R.Inf.11 Rainfall Inflow Adjp.Manl Average Outflow Storage R.Inl.li Rabd.il Inflow Adjustment Average Outflow Sharpe
Duration Ink/tally Volume Faclor Outflow Volume Volume Duration Intensity Volume Factor Outflow Volum. Volume
minuW ind,ear ht cubic feel ete cubic lent cubic feel minutes Ind,e.lhr cubic feel d. whiff feel abk Mt
anvil) (output) louteul) fauteuil Ieuloull (atpulL faulputi hnputl 10010.4) laulpull tuulpug 10ulou 1 loulodt foulppfl
o moo o 0.00 1 moo I o o o 0.00_ 1 _o __ 6a_ 0.00 _ 0 _ o _
30 2,00 10_303 0.74 510 0.002 400 __ 30_..___... 4.21 24,227_ 474 6.65 -
30 0,903 14,744
c _._
e0 r 1..1 _� 13363 0.02 4,44 14722 y360 _ -O0 "_- 2.77-- - 31,150 DM 4.66 14,722 14,434
OD _ I 1.21 15_118 0.50 4.34 23,401 •4,346 __ 00 _ 200 __ _ 36,273 ,_ 0.55 - 4.54 _ _ 23,401 11,011
...
120 0.00 10.307 0,50 - 4.10 •-30,20► •13,014 120 1,70 __ 5423• 000 4.10 30,201"_� 4036
160 _ 0.64
17_388 ^ 0.55 _ - _4,10 34040 __-14555 160 -.• 1.44 40.673 0.06 4.10 32040 3.033 -
160 0.73 10_220. ....0.54.. 4,04 ..- 43675 •26..60 180 1.24 _ 42,614 0.54 4.04 ___ 43,070 --- -1,105
._____._.-.. - - ----
._,. 210 I 0.63 15,535 _ 063 400 5D418 -31,404 210 _ 1,12 44,102 0.13 _ 4.00 55616 -0,235
240- -- D_69 14603 0.63 ""-107 " 57,157 "-"-STAIN "--" 24D -- _tA2 1 46040 _ 0.53 107 67,757 _ _ -►1,604• "~
-.. 270 _ 064 •- 23126 0.63 •_ _ 104 • 63.607 • • •.3,770 _ 270 _ D_W 46.907 aa3-- 1w 63,097 '] .1.,034
300 0.60 20,637.." 0.52 102 _ra�___. -04060 300 0_80 .0.164 6.52 '- •..302 74030 •22.452_
330 0 41 1--21_105 052 101 . 77_376 -sane _330 - .._ 4)00 40,246 012 _-- 3.w..... • 77_375 .20.520
380 0.43 21,636 -- 032 100 64,114 -02.570 300 575 - - 54360 0_62 3 BD 04.114 _ •73401
300 I 041 21.041• 052 ••. 166 . _00.603 • ..4.913 _- 300-_ 0.70 j. 51,706 0.52 ".. 184_ __...00053 42660 _
420 _I a35 _22.316_ 0.52 I _ 3.87 I 07.503 42270 420 M00 1 62.070 I 0.52 -• •-367 07.503 42617~
400 L 0.30 22.673 11.62 3110 104,732 -05650 400 003 I •__ 63_604__ 402 .... 3.60 - 104.512 -61.427_.
460 0.35 33,006 0.52 3.64 1►3,071 •66_003 4ao 0.60 -j 83687 -0.52 2_56 - 111,071 -67,306
610 0.33 23327 0,55 3.65 _ 117,010 •04,464 510 •" 0.67 84,430 0.51 �•_ 3.05_"�-�117,610 _ 43,300
'Tali-- - 0.72 22,025 0 61 I 164 __ 124540 __ •100,025_ 640 0.55 - 56,137 0.61 - 364 ►2.,640 _ _ -00,412 _
0711 030 23.010 - 031 l _ 3.84 131,260 -107,370_ 570 0.62 55.812 2,51 7.84 131,280 -75,477
_ ao0 020 x4.1.5 • Qa1 I iai 13ame •113,.32 _ 000 OAR) -I 50.457 0.51 303 17.075 6t,eTo�
O 30 _020 I 24.481 _f oat 103 144.767 .120305 030__ 0.40 - 67.077 0.51 `102 114,767 -57.000
MD 027 24.718 061 I 117 151,606--- 125.700 050 mar _ 67.972 451 163 151,600 _ -13,634
0 222 24.502 •031 . 3.02 -711 164246 .204 590 0.48 outs 00031 SBZ _ 16a245 •100000 _
720 0 25 25,190 0.01 , 122_ _104.085_ •130,758 72D D.44 50.790 __-..0.51 _- -3.62 164.665 "•"-104106
750 0.24 22426 0 61 •3.82 171,724 --140,296 750 142 50,333 031_-_ -"362 "- 171,724 -112,301
700 1 024 25,045 451 i 3,61 175,.03 . .._ ._ _-._
••,_162_614_ 700 0.41 _ E0050 I 0.61 301 170.463 1"^11 a0t5 ,
010 023 24464 0.65 I 3.81 _ 166,222 -154336 110 0.40 50.361 0.61 341 585,202 •124,662
642 •0.22 2.072 a61 -181 - !., 101.041 "•-106,400 640 ""- 470 I 64876 061 3 9I 101,0.1 •131.100
.___. _.-.. •-20,27- . 0 . .11 ---172.455 " 67o._.._ 436 1 61.2110 _---- 051 -5.11 106,541 -137,372 _
e 7o 0.22 ! 2e n4 051 I 311 104,681
...' -_. ..�- � . -•'-" -17aWY 900 "_0.37 --11.767 0.61 7,00 204420 -►43650
..▪. ... 621 ! 22.71 -air I 100 204420 . =--._ -
_0�0 0_71 1 20,002_ o.e1" a" a.00 212.151 _-164,407 930 .._ 0.35-- I"62,xta 5.65 - 3_80 _-_212,156.. "-140046
630 I" "0.25 25.146 -031 3.60 -_} 210666 102,040---ego ..0.35 1 "62,140 061.. -"1eD 310,.05 _tae tsl
_ 160 _.. 024 27.1-0 • • 001 • 380 I 225.037 •104.608 050 0.34 I 03071 "�- 0.61 3..a 226637 -•702606_
111!0 I 0.19 ( 27�I27 fief 160 ) 232ari 405,170 1220 0,3 i•
!3404 • 051 182 232,377 486.693
1060 0119 I 17,100 • 651 I 160 _ __230.116 •x11.736 1960 0.13 03600 00..61 100 230.110 i75i2e
iaw 0.15 I 22,$41 031 • _e7o i46.tis6 .xla3ae 1080 0.30 3 .84.282 I ast 130 x45.656 1 •181.573 .
1110 5.-10 ( 27,714 -Eli I •070 I 652.562 . _224680 • •""1139 "eat I 04,867 -+ obi" 33-70 ._`..252.50, .187,0-
1140 016 27,076 5.41 370 i 240,07 -231.466_ _ 1340 0.20 I 05,044 0"51 • • 0,76 • 260.337...; ••104.210
7170 0_77 26,5 4 065 3.70 260,073 -232078 1175 0.30 I 62,453 0.61 370 _268.073 [ -200.560_
1200 1 0.17 26164 0.61 ) 3.70 I 277,872 44.1_023 1207 020 1 06776 061 I 370 272.012 I -257_037
i
12311 I 017 j 24340 j 037 • 7.70_ 270,557 I__•261.211_ 1230 " "620 66.120 I 4.61 170 275651 213422
1340 _ I 0.18 2&480 0.51 _ , 375 ) 204,200 { -267,601_• _ 1220 0.20 66.470 031 170 256,290 I .210,014
1290 I 0 10 ! 24635 051 ' 179 1 203.029 -204,704 1200 025• ' 60,•17 I 0_51 I 3 70 260.329 j -220,213
...
1320 I 0.35 x0_775 051 r 3,7(5 200769 -270900 1320 027 I 67011 0.61 I 33-76 209.760 -212216
1750 0 75 I 24011 0.51 l 176 300,628 -277_510 5350 527 67,470 I 2.67 I 370 376,556 -236.220
5'3 I 015 24057 Oat 378 313,247 ._264,100 1360 028 i 07101 I 0.61 3,70 313247 .545,4411
1415 s 015 I 70,703 037 170 110.080 •200,704 1410 f 025 l 6.115 I 9.61 STe 310280 I 4.16.9"
14.0 • Ole i 29320 0.55 176 120,725 407220 14.D 02b 82425 t 0,51 378 326725 45x297
ii70 0.1
I 4 10.4—ii "006 7.7e 233•305 304
- .Cca 1470 0.25 6[,730 I050 370 333..65 1 404730
1600 0.14 1 20,580 I _0_SD • 3.74 _ 3402. -415,2la 1500 025 ' 60_038 pea 176 340..204_ -271,706
1570 0.14 1 24713 1 450 3 75 ' 340,043 -377.230 1535 224 00,332 • 060 3 70 "340.043 -277.011
1500 1 014 20.630 0.60 I 3 78 1 353,002 -323,544 1505 0.24 10,023 I 0.50 I• 170 353,6.2 1 -264.050
1500 614 29001 050 170 700.421 •110,401 1500 ! 023 • 54010 I 050 170 260421 400611
1620 0.13 33,002 180 376 367,101 •137,0713 coda a.23 I 70,103 • 0.60 I 178 167,161 -394.507
1454 0.13 20.501 5.00 336 373.000 -243,600 1660 123 • 70,472 030 3.10 371.000 .303,478
1110 013 30,376 055 376 305,0.9 I .60.421 7060 0.73 70738 ass 7e 381035 .300,603
1710 I 013 1 34435 Tao ,I 3.70 3977,376 -365_943 1710 072 • 71,017 060 • 3.76 303,330 •310.362
1740 013 30.000 050 ! 370 304.117 I •163,560 1725 0:22 15,283 0.60 i 3.70 30450i -3ia.sia
3770 cis 20,002 gag 337 i0ae57 -375150 1772 ' 052 75,046 0.55 ` 077 400.57 -336,110
two
1 8.12 30.773 0.63 177 • 007..50. -372623 1800 I 0.21 ' _
71.806 065 I 3 77 I 407.590 •335.750
Mod.FAA Minor Slarag.Velum.(cubic ft.)s 100 Mod FAA Major Storage Volum.(cubic 1t.)0 14,435
Mud FAA Minor Waage Volume(.ere.R.)a 0.0092 Mud FAA Melee Storage Volum.(.ore•II 1° 0.1714
UDFCD DETENTION VOLUME ESTIMATING WORKBOOK Version 2.2.Released Januar,2010
'FA O.1.10en f utei 2014.650 evi..minery.M0.90.d FAA 8R2/2214.4 ea FM
DETENTION VOLUME BY THE MODIFIED FAA METHOD
(See USDCM Volume 1 Storage Chapter for description of method)
Project:Varra Construction
Basin ID: Lots A 8 B Detention Pond
Inflow and Outflow Volumes vs.Rainfall Duration
500,000
I
400,000 — — _ - -__.. — — —--- — --
I
300,000 ------ - — -- — -- —
zoo,00D — -
100,000 --
—o
1
0 -
a 0 co • 4a0 6 800 1 0 1ar0 1.10 1610 1210 2000
. oB po°°000
o •000 • •
X700,000 _°n —
••
- •
0°°°°°'°000 ••••
-200,000 — _ --•,00000I o•••••
S.
—
-300.000 — — -- °°°°o •.
00°•000
•••••O
o00O 00
-400,000 -- - — - --
I
-500.000
Duration(Minutes)
dMma.aeon lneo.Polum. Mxn,vmmamou.vewm. a •im,seam elnnc.vale,,. wqo.mum l,men vale,,. M.w te,,Cana.vale,,. . M.le,lea..a,o•.c.vm.m.
UDFCD DETENTION VOLUME ESTIMATING WORKBOOK Version 2 2,Released January 2010
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