HomeMy WebLinkAbout20152623.tiff WELD COUNTY
CODE ORDINANCE 2015-11
IN THE MATTER OF REPEALING AND REENACTING, WITH AMENDMENTS, CHAPTER 8
PUBLIC WORKS AND CHAPTER 23 ZONING, OF THE WELD COUNTY CODE
BE IT ORDAINED BY THE BOARD OF COUNTY COMMISSIONERS OF THE COUNTY OF
WELD, STATE OF COLORADO:
WHEREAS, the Board of County Commissioners of the County of Weld, State of
Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is vested with
the authority of administering the affairs of Weld County, Colorado, and
WHEREAS, the Board of County Commissioners, on December 28, 2000, adopted Weld
County Code Ordinance 2000-1, enacting a comprehensive Code for the County of Weld,
including the codification of all previously adopted ordinances of a general and permanent nature
enacted on or before said date of adoption, and
WHEREAS, the Weld County Code is in need of revision and clarification with regard to
g
procedures, terms, and requirements therein.
NOW, THEREFORE, BE IT ORDAINED by the Board of County Commissioners of the
County of Weld, State of Colorado, that certain existing Chapters of the Weld County Code be,
and hereby are, repealed and re-enacted, with amendments, and the various Chapters are
revised to read as follows.
CHAPTER 8
PUBLIC WORKS II
Delete Article XI from Chapter 8, in its entirety. bQ n 0�- Cx( tlo tti
CHAPTER 23 — _u�UL6\44144__
ZONING ►Amend Section 23-1-90. Definitions. 1rLS..4p ±1-1,1-4
For the purposes of this Chapter, certain terms or words used herein shall be interpreted
as defined in this Section. The following specific words and phrases, when appearing in this
Chapter in uppercase letters, shall have the meanings stated in this Section:
ACCESSORY BUILDING or USE to NONURBAN SCALE DEVELOPMENT— No change.
Add NON-URBANIZING: An area greater than a '/4 mile from municipal boundaries, as amended.
Add URBANIZING: An area within 1/4 mile from municipal boundaries, as amended.
Remainder of Section — No change.
Chapter 23 Article XII will be added in its entirety.
PAGE 1 2015-2623
4135073 Pages: 1 of 12 ORD2015-11
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes. Clerk and Recorder. Weld County. CO
■III Ml�ll���r�i I�'I��i��+l��' J���X�i �LJ4�fa�+l I. 1a i, Ill III
ARTICLE XII
Storm Drainage Criteria
Division 1
General Provisions
Section 23-12-10. Intent.
A. The intent of the Weld County Storm Drainage Criteria is to provide minimum standards
to preserve and protect the public health, safety and general welfare in the
unincorporated lands of the County, pursuant to authority granted by Part 4 of Article 15
of Title 30, and Article 35 of Title 30, C.R.S.
B. Adequate drainage is necessary to preserve and promote the health, safety, general
welfare, and economic well being of the County. Drainage is a regional issue involving
multiple governmental jurisdictions and affecting all property parcels. This makes it
especially critical for drainage systems and programs to address both public and private
needs. The County should be directly involved to provide coordination and master
planning for area-wide drainage facilities.
C. Drainage plans should adhere to generally accepted engineering principles and
practices and should conform to applicable laws and regulations.
D. Application of these policies is supported by technical drainage criteria and data. When
designed and implemented in a comprehensive manner, drainage facilities can be
provided in a manner that will avoid water-related damage to infrastructure, maintain or
improve water quality, and enhance the health, safety, and general welfare of the
County.
Section 23-12-20. Adoption of Storm Drainage Standards.
A. The Urban Drainage and Flood Control District's "Urban Storm Drainage Criteria
Manual," (UDFCD Manual)consisting of Volume 1, Volume 2, and Volume 3, as currently
published or hereafter amended, is hereby adopted by reference, with the amendments
and additions which are set forth herein. All references to "District" or "The District"
within the UDFCD Manual shall be replaced with "Weld County". The provisions of this
Article shall be known as the "Weld County Storm Drainage Criteria." All facilities for
storm water management on properties located within the unincorporated lands of the
County, whether public or private, shall be designed and constructed in accordance with
such criteria, unless a master drainage plan specific to the area of the site has been
approved by the County. The Weld County Storm Drainage Criteria shall be available
on the Weld County Planning Department's Website.
B. The criteria and procedures contained in this Article XII are intended to supplement the
UDFCD Manual in ways specific to Weld County. In the case of a conflict between the
UDFCD Manual and the supplemental criteria and procedures in this Article XII, such
supplemental criteria and procedures shall take precedence over the UDFCD Manual.
4135073 Pages: 2 of 12
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes. Clerk and Recorder, Weld County. CO
■III l4.1�1l�:I��I���'L#�ti hil�:l�r��M�,�Iti'I�I LfII, I����:IrY��r�� 1I 111
PAGE 2 2015-2623
ORD2015-11
Section 23-12-30. Drainage Policy.
A. The Policy of Weld County shall be to pursue a jurisdictionally unified drainage effort to
assure an integrated drainage system and to cooperate with other regional and local
planning agencies on drainage matters.
B. For new development, the Policy of Weld County is to prohibit un-detained discharges to
roadside ditches located in the County right-of-way unless granted by a variance.
C. Except as set forth below, the Policy of Weld County shall be to require regional and/or
on-site detention for all future developments. Temporary or interim detention/retention
may be required if the downstream regional facilities have not yet been constructed per
the applicable master plan for that location. Stormwater retention facilities are normally
not allowed in Weld County, but will be considered for special circumstances.
D. The Policy of Weld County is to require detention of runoff from the 1-hour, 100-year,
storm falling on the developed site and release of the detained water at the historic
runoff rate of the 1-hour, 5-year storm falling on the undeveloped site for URBANIZING
areas and the historic runoff rate of the 1-hour, 10-year storm falling on the undeveloped
site for NON-URBANIZING areas. Historic is defined as an undeveloped site with a
2.0% imperviousness. If the urbanizing jurisdiction has adopted a different historic
runoff rate than that stated in this subsection, then the urbanizing jurisdiction runoff rate
shall apply.
E. Weld County will not accept any detention or retention pond that does not drain in less
than 72 hours, causes injury to water rights, or is in violation of state or federal law.
Upon evaluation, improvements may be necessary to downstream capacity.
F. Exceptions to stormwater detention shall not jeopardize the public health, safety, and
welfare of public and private property and shall be limited to the following:
1. No stormwater detention will be required for sites that meet any of the following
conditions. Requirements of the Municipal Separate Storm Sewer System (MS4)
areas remain applicable.
a. Use by Right or Accessory Use in the A (Agricultural) Zone District.
b. Zoning Permits in the A (Agricultural) Zone District.
c. A second dwelling permit in the A (Agricultural) Zone District.
d. Towers including, but not limited to, cell, wind, and telecommunication towers.
e. Pipelines or transmission lines.
f. Gravel pits if the stormwater drains into the gravel pit.
g. Residential developments where all the following conditions exist:
1. Nine (9) lots or fewer.
2. The average lot size is equal to, or greater than, three (3) acres per lot.
3. Downstream roadway criteria are not exceeded.
PAGE 3 2015-2623
4135073 Pages: 3 of 12 ORD2015-11
08/19/2015 11 :12 AM R Fee:$0.00
Carly Koppes, Clerk and Recorder. Weld County, CO
OHM I
4. The total post-development imperviousness for the rural residential
development does not exceed ten percent (10%), assuming that all internal
roads and driveways are paved, or will eventually be paved.
h. Development of sites where the change of use does not increase the
imperviousness of the site.
i. URBANIZING areas where the total project stormwater runoff of less than, or
equal to, 5 cubic feet per second (cfs) for the 1-hour, 100-year, storm event.
j. NON-URBANIZING areas where the total project stormwater runoff of less than,
or equal to, 10 cfs for the 1-hour, 100-year, storm event.
k. Parcels with total area less than, or equal to, a 1.0 gross acre.
I. Individual parcel with an unobstructed flow path and no other parcel(s) between
the Federal Emergency Management Administration (FEMA) regulatory
9 Y 9 9 rY
floodplain channel and the project.
m. A parcel greater than 1 gross acre and less than, or equal to, 5 gross acres in
size is allowed a onetime exception for a new 1,000 sq ft building or equivalent
imperviousness.
n. A parcel greater than 5 gross acres in size is allowed a onetime exception for a
new 2,000 sq ft building or equivalent imperviousness.
o. Approved by a variance.
Section 23-12-40. Rainfall.
The designer shall use the most appropriate and best available data for the project area in
determining the rainfall quantities.
Section 23-12-50. Runoff.
A. The Rational Method should not be used to determine runoff for basins larger than 160
acres. In areas located in the southwest portion of Weld County and where areas are
larger than 160 acres that have drainage characteristics similar to an urban area, the
Colorado Urban Hydrograph Procedure (CUHP) is an acceptable model for determining
runoff amounts. The CUHP model can be used for basins from 0 to 3,000 acres. The
parameter adjustments provided in the runoff chapter of the UDFCD Manual (Volume 1)
should be used when dealing with basins that are larger than 160 acres.
B. The CUHP model is not applicable in non-urban areas, including those areas in Weld
County that are outside of the Denver Metropolitan area. The U.S. Army Corps of
Engineers (USACE) HEC-HMS model is more applicable for mixed suburban-agricultural
areas. The HEC-HMS model can be used on watersheds and drainage basins larger than
160 acres provided the modeling follows the parameters in the HEC-HMS User's Manual,
the HEC-HMS Technical Reference Manual, and the HEC-HMS Application's Guide.
C. Weld County in its discretion may accept other methodologies as deemed appropriate by
the design engineer.
''AGE 4 2015-2623
4135073 Pages: 4 of 12
08/19/2015 11:12 AM R Fee:$0.00$0.00 ORD2015-11
Carly Koppes. Clerk and Recorder, Weld County, CO
11111
Section 23-12-60. Street Drainage.
A. Design Depth Criteria.
1. The primary design objective is to keep the encroachment of stormwater on the street
or road below an acceptable limit for a given flood return period. When stormwater
collects on a street and flows down a gutter or swale, the stormwater encroaches into
the roadway. If left unchecked, the encroachment will hinder traffic flow and may
become hazardous. The maximum encroachment depth is outlined in the table below:
Road Encroachment
Minor Major
Road Design Design
Max Encroachment
Classification Storm Max Encroachment Storm
over crown
Local 10 yr May spread to crown 100 yr 18"
Collector 25 yr Leave one lane open 100 yr 12"
Arterial 50 yr No encroachment in lanes 100 yr 0"
B. Inlets.
1. The design guidelines provided in the streets/inlets/storm sewers chapter of the
UDFCD Manual (Volume 1) should be used when designing stormwater inlets. The
standard inlets permitted for use in Weld County streets are shown in the following
table:
Inlet type permitted (CDOT Types)
Curb opening inlet Type R All street types with 6 inch vertical curb
Grated inlet Type C All streets with a roadside ditch or swale
Grated inlet Type 13 Alley or private drives with a valley gutter
Combination inlet Type 13 All street types with 6 inch vertical curb
PAGE 5 2015-2623
4135073 Pages: 5 of 12 ORD2015-11
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes. Clerk and Recorder, Weld County. CO
1111 11111
2. In order to account for factors which decrease the capacity of the inlets—such as
debris plugging, pavement overlaying, and variations in design assumptions—the
theoretical capacity calculated for inlets is to be reduced by the factors presented in
the following table for standard inlets in Weld County.
Percent of
Condition Inlet Type Theoretical Capacity
Allowed
Sump or continuous grade CDOT Type R
5 ft length 88
10 ft length 92
15 ft length 95
Continuous grade Combination Type 13 66
Sump Grated Type C 50
Grated Type 13 50
Combination Type 13 65
C. Pipes.
1. The design guidelines provided in the streets/inlets/storm sewers chapter of the
UDFCD Manual (Volume 1) should be used when designing stormwater pipes.
2. The Department of Public Works should be contacted to determine which types of
storm sewer pipes are permissible for use in public rights-of-way or public drainage
easements.
Section 23-12-70. Major Drainage.
A. Design Flows.
1. The major drainage system must be able to convey the fully developed flow from a
watershed for the 1-hour, 100-year event without significant damage to the system.
B. Open Channel Design Principles.
1. Grass-lined open channels conveying less than 50 cfs may reduce the minimum
1.0-foot freeboard requirement to the freeboard required to convey 1.33 times the
24-hour, 100-year design flow. The reduced freeboard may only occur if a 1.0-foot
minimum freeboard is not physically possible and a variance request is submitted.
"AGE 6 2015-2623
4135073 Pages: 6 of 12 ORD2015-11
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes, Clerk and Recorder, Weld County. CO
NIJ,in III
2. Maximum side slopes may be as steep as 3H:1 V. However, the design engineer
should address how the channels will be maintained since it may not be safe to mow
on slopes that are greater than 4H:1 V.
Section 23-12-80. Culverts.
A. Sizing.
1. The Department of Public Works should be contacted to determine which types of
storm sewer pipes are permissible for use in public rights-of-way or public drainage
easements.
2. Culverts must be designed to the following maximum headwater to depth HW/D
requirements.
Design Storm HW/D
10 Yr 1.0
100 Yr 1.5
B. Materials.
Culverts that are to be installed in a public right-of-way that is routinely burned must be
made of either concrete or metal. Plastic pipes will not be allowed in public rights-of-way
that are subject to weed burning.
Section 23-12-90. Storage.
A. Detention Criteria.
1. Detention ponds shall be sized to store the stormwater runoff generated by the
1-hour, 100-year storm falling on the developed site and release of the detained
water at the historic runoff rate of the 1-hour, 5-year storm falling on the undeveloped
site for URBANIZING areas and the historic runoff rate of the 1-hour, 10-year storm
falling on the undeveloped site for NON-URBANIZING areas. Historic is defined as
an undeveloped site with a 2.0% imperviousness.
2. The detention pond must include volume for the water quality capture volume. Water
quality capture volume may be included as a portion of the total 100-year detention
pond volume.
3. Off-site flows can be routed as follows:
a. Over the spillway; or
b. Routed around the site.
4. The elevation of the top of the detention pond embankment, except at the spillway,
must be a minimum of 1-foot above the 100-year water surface elevation in the
detention pond.
PAGE 7 2015-2623
4135073 Pages: 7 of 12 ORD2015-11
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes, Clerk and Recorder; Weld County, CO
III �1�1r�'G�1�r�«'i'a'r1Fic r i :i':l;EP�'kg. iI II
5. There should be no more than two levels of controls, in addition to the water quality
capture volume controls, for detention ponds. Outlet works should be sized and
structurally designed to release at no more than the 1-hour, 5-year historic release
rate in URBANIZING and 1-hour, 10-year historic release rate in NON-URBANIZING
without structural or hydraulic failure. Historic is defined as an undeveloped site with a
2.0% imperviousness. The outlet pipe must contain a minimum of two concrete cutoff
walls embedded a minimum of 18 inches into undisturbed earthen soil. The cutoff
walls must be a minimum of 8 inches thick. The outlet pipe bedding material must
consist of native earthen soil, not granular bedding material, to at least the first
downstream manhole or daylight point.
6. Each detention pond shall contain an emergency spillway capable of conveying the
peak 100-year storm discharge draining into the detention pond. The invert of the
emergency spillway must be equal to, or above, the 100-year water surface
elevation. The depth of flow out of the emergency spillway shall be less than 6
inches. The spillway must have effective erosion protection. In order to protect the
emergency spillway from catastrophic erosion failure, buried riprap shall be placed
from the emergency spillway downhill to the embankment toe of slope and covered
with 6 inches of topsoil. The riprap must be sized at the time of final engineering
design. Grouting of the riprap may be required.
7. In order to prevent damage to publicly-owned infrastructure (roads, roadside
ditches), a concrete cutoff wall 8 inches thick, 3 feet deep, and extending a minimum
of 5 feet into the embankment on each side of the emergency spillway opening, is
required on all privately-maintained detention ponds and required on all regional
detention ponds. The concrete cutoff wall permanently defines the emergency
spillway opening. The emergency spillway elevation must be tied back into the top
of the embankment using a maximum slope of 4:1.
8. The design of the detention facility must provide evidence that the pond will drain in
less than 72 hours. A detention pond that does not drain in less than 72 hours, can
cause injury to water rights, or is in violation of State or Federal law will not be
accepted.
B. Retention Criteria.
1. Retention facilities are not allowed in Weld County without the issuance of a
variance.
2. Retention facilities must be designed to contain 1.5 times the volume of the runoff
generated by the 24-hour, 100-year storm, plus 1 foot of freeboard.
3. The design of the retention facility must include an emergency spillway and must
show that a spill will not adversely impact downstream properties or residences. The
spillway must be designed in accordance with the detention pond spillway
requirements.
4. The design of the retention facility must provide evidence that the pond will drain
through the bottom (sides slopes cannot be used in calculation) in less than 72
hours. A retention pond that does not drain in less than 72 hours, can cause injury to
water rights, or is in violation of state or federal law will not be accepted.
PAGE 8 2015-2623
4135073 Pages: 8 of 12 ORD2015-11
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes, Clerk and Recorder, Weld County CO
11111
C. Erosion Protection Design Criteria.
Erosion protection for storage facilities needs to be designed to ensure that the
sediment does not leave the site or impact downstream properties. It may be necessary
to install straw bales, riprap, erosion control logs, erosion control blankets, etc. on the
storage facility side slopes to ensure that erosion does not occur until the reseeded
vegetation is established. The Best Management Practices outlined in the UDFCD
Manual (Volume 3) should be used.
Section 23-12-100. Revegetation.
A. Weld County utilizes the information provided in the Revegetation Chapter of the
UDFCD Manual (Volume 2), and the Best Management Practices Chapter of the
UDFCD Manual (Volume 3). Weld County has seed mixes that are applicable to areas
of the County that are highly recommended. These seed mixes can be found under the
Weld County Public Works Website, Weed Management Section. If noxious weeds, as
listed in Weld County Code Chapter 15, exist on-site, the appropriate steps need to be
taken before, during, and after work is completed to control their spread.
B. Seeding and Planting.
In addition to the site preparation guidelines outlined in the revegetation chapter of the
UDFCD Manual (Volume 2), if mulching with straw, the straw must be free of seeds and
weeds.
Section 23-12-110. Stormwater Quality.
A. A water quality feature is intended to improve water quality from the impacts of site
development. A water quality feature can be an existing low spot on the property that
currently collects water or an excavated area. The size required is based upon site
imperviousness. This depression is intended to allow stormwater runoff from the site to
collect and settle out any contaminants prior to flowing offsite to neighboring properties
or downstream waterways.
B. An accepted methodology for a water quality feature design can be found in the UDFCD
Manual, Volume 3, Best Management Practices.
Section 23-12-120. Best Management Practices.
Weld County uses the Best Management Practices that are outlined in the UDFCD Manual
(Volume 3) Best Management Practices.
Section 23-12-130. Maintenance.
A. Culverts located outside County-maintained road rights-of-way are not maintained by
Weld County. The owners of those culverts are responsible for their maintenance.
Culverts that are part of a subdivision drainage plan are maintained by the respective
homeowner's association. Those culverts should be maintained and cleaned out
annually, per the drainage report maintenance plan, or on an as-needed basis to ensure
proper drainage of the subdivision.
PAGE 9 2015-2623
4135073 Pages: 9 of 12 ORD2015-11
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes: Clerk and Recorder; Weld County. CO
1111 MIr1 � hail frai all MICA ki III II I
B. To assist drainage pond owners with maintenance, an operations and maintenance
manual for detention facilities and associated infrastructure must be developed and
included with the final drainage report.
C. The property owner/developer, not Weld County, is responsible for site maintenance
and revegetation.
D. Weld County will require that all submittals include an operations and maintenance
manual for all water quality and detention pond facilities. The operations and
maintenance manuals shall also be distributed to the applicable homeowners'
association and/or business park association (or equivalent). The operations manuals
will include instructions on safe and correct operations, repair and maintenance of all
installed equipment and facilities and recommended inspection schedules.
E. Access must be provided to the drainage facilities for long term maintenance.
Section 23-12-140. Enforcement.
The enforcement of this Article shall be in accordance with Article X of this Chapter.
Section 23-12-150. Stormwater Drainage Criteria Variances.
The following variance procedures are intended to allow additional exceptions to the code
explicitly listed in Section 23-12-30 provided certain requirements are met. Subsection A
below is intended to be a lower cost option which allows anyone to apply for a variance with
or without stamped engineering documentation. Subsection B below is intended to be
used when more detailed analysis and engineering support is required.
A. An applicant may request a variance for their site when conditions do not meet the
drainage exemptions described previously and impacts to the site and offsite properties
are insignificant. Requests will be reviewed by the Planning Director or his/her designee.
No variance will be considered if it may jeopardize the public health, safety, welfare and
public and private property. In order to be granted, the variance request must:
1. Demonstrate that granting of the variance will still adequately protect public health,
safety, and general welfare.
2. Demonstrate there are no adverse impacts, from stormwater runoff, to the public
rights of way and/or offsite properties as a result of the project.
Any engineer's supporting documentation or analysis has to be signed and stamped by
a licensed PE in the state of Colorado.
If the applicant's variance request is denied for not satisfying the above criteria and in
the sole discretion of the planning director or his or her designee, the applicant has the
option to follow the variance request in Subsection B below or appeal the denial to the
Board of Adjustment.
B. The applicant's engineer may request a variance. The variance request shall be
stamped and signed by a professional civil engineer licensed to practice in the State of
PAGE 10 2015-2623
4135073 Pages: 10 of 12 ORD2015-1 1
08/19/2015 11 :12 RM R Fee:$0.00
Carly Koppes. Clerk and Recorder. Weld County, CO
■III ki lid par f`l'y JklitillitrPI RIF;'ii4f`, 17,411iiiii BI II I
Colorado. Requests will be reviewed by the Planning Director or his/her designee. In
order to be granted, the variance request must:
1. Describe the design criteria of the Weld County Code of which a variance is being
requested.
2. Describe the proposed alternative with engineering rationale which supports the
intent of the Weld County Code.
3. Meet the design intent of the Weld County Code.
4. Demonstrate that granting of the variance will still adequately protect public health,
safety, and general welfare.
5. Demonstrate there are no adverse impacts, from stormwater runoff, to the public
rights of way and/or offsite properties as a result of the project.
An applicant can appeal to the Board of Adjustments the Director of Planning Services
decision regarding the variance per Article VI of this chapter.
C. Variance requests, if accepted, are not precedent setting and are based upon specific
site constraints.
BE IT FURTHER ORDAINED by the Board that the Clerk to the Board be, and hereby is,
directed to arrange for Colorado Code Publishing to supplement the Weld County Code with the
amendments contained herein, to coincide with chapters, articles, divisions, sections, and
subsections as they currently exist within said Code; and to resolve any inconsistencies regarding
capitalization, grammar, and numbering or placement of chapters, articles, divisions, sections,
and subsections in said Code.
BE IT FURTHER ORDAINED by the Board, if any section, subsection, paragraph,
sentence, clause, or phrase of this Ordinance is for any reason held or decided to be
unconstitutional, such decision shall not affect the validity of the remaining portions hereof. The
Board of County Commissioners hereby declares that it would have enacted this Ordinance in
each and every section, subsection, paragraph, sentence, clause, and phrase thereof irrespective
of the fact that any one or more sections, subsections, paragraphs, sentences, clauses, or
phrases might be declared to be unconstitutional or invalid.
PAGE 11 2015-2623
4135073 Pages: 11 of 12 ORD2015-11
08/19/2015 11:12 AM R Fee:$0.00
Carly Koppes, Clerk and Recorder; Weld County: CO
101 M lid RITf'Iti.!Irilidri+itN3II L!1 FY. Ill 111
The above and foregoing Ordinance Number 2015-11 was, on motion duly made and
seconded, adopted by the following vote on the 3rd day of August, A.D., 2015.
BOARD OF COUNTY COMMISSIONERS
W D COUNTY, OLORADO
ATTEST: datAgeo
�• ��
Barbara Kirk eyer, C air
Weld County Clerk to the Th3)-4-Leg...----- —
/ Mike Freeman, Pro-Tern
D ty Clerk to the oard � 1. EXCUSED
Z an P. Con ay
APP D RM: V 1861 itt , a Y7
t %,�►�` I e A. Cozad
ty Attorney � ,N •\
♦,,,,,,,.I Steve Moreno
Publication: May 20, 2015
First Reading: June 22, 2015
Publication: July 1, 2015, in the Greeley Tribune
Second Reading: July 13, 2015
Publication: July 22, 2015, in the Greeley Tribune
Final Reading: August 3, 2015
Publication: August 12, 2015, in the Greeley Tribune
Effective: August 17, 2015
PAGE 12 2015-2623
4135073 Pages: 12 of 12 ORD2015-11
08/19/2015 11 :12 AM R Fee:$0.00
Carly Koppes. Clerk and Recorder. Weld County CO
lIII RIF/1Rn LT'I"I fig In iii I1 04f,101,0KRiiiiiii 1I III
WELD COUNTY
CODE ORDINANCE 2015-11
IN THE MATTER OF REPEALING AND REENACTING, WITH AMENDMENTS, CHAPTER 8
PUBLIC WORKS AND CHAPTER 23 ZONING, OF THE WELD COUNTY CODE
BE IT ORDAINED BY THE BOARD OF COUNTY COMMISSIONERS OF THE COUNTY OF
WELD, STATE OF COLORADO:
WHEREAS, the Board of County Commissioners of the County of Weld, State of
Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is vested with
the authority of administering the affairs of Weld County, Colorado, and
WHEREAS, the Board of County Commissioners, on December 28, 2000, adopted Weld
County Code Ordinance 2000-1, enacting a comprehensive Code for the County of Weld,
including the codification of all previously adopted ordinances of a general and permanent nature
enacted on or before said date of adoption, and
WHEREAS, the Weld County Code is in need of revision and clarification with regard to
procedures, terms, and requirements therein.
NOW, THEREFORE, BE IT ORDAINED by the Board of County Commissioners of the
County of Weld, State of Colorado, that certain existing Chapters of the Weld County Code be,
and hereby are, repealed and re-enacted, with amendments, and the various Chapters are
revised to read as follows.
CHAPTER 8
PUBLIC WORKS
Delete Article XI from Chapter 8, in its entirety.
CHAPTER 23
ZONING
Amend Section 23-1-90. Definitions.
For the purposes of this Chapter, certain terms or words used herein shall be interpreted
as defined in this Section. The following specific words and phrases, when appearing in this
Chapter in uppercase letters, shall have the meanings stated in this Section:
ACCESSORY BUILDING or USE to NONURBAN SCALE DEVELOPMENT — No change.
Add NON-URBANIZING: An area greater than a 1/4 mile from municipal boundaries, as amended.
Add URBANIZING: An area within IA mile from municipal boundaries, as amended.
Remainder of Section — No change.
Chapter 23 Article XII will be added in its entirety.
PAGE 1 2015-2623
ORD2015-11
ARTICLE XII
Storm Drainage Criteria
Division 1
General Provisions
Section 23-12-10. Intent.
A. The intent of the Weld County Storm Drainage Criteria is to provide minimum standards
to preserve and protect the public health, safety and general welfare in the
unincorporated lands of the County, pursuant to authority granted by Part 4 of Article 15
of Title 30, and Article 35 of Title 30, C.R.S.
B. Adequate drainage is necessary to preserve and promote the health, safety, general
welfare, and economic well being of the County. Drainage is a regional issue involving
multiple governmental jurisdictions and affecting all property parcels. This makes it
especially critical for drainage systems and programs to address both public and private
needs. The County should be directly involved to provide coordination and master
planning for area-wide drainage facilities.
C. Drainage plans should adhere to generally accepted engineering principles and
practices and should conform to applicable laws and regulations.
D. Application of these policies is supported by technical drainage criteria and data. When
designed and implemented in a comprehensive manner, drainage facilities can be
provided in a manner that will avoid water-related damage to infrastructure, maintain or
improve water quality, and enhance the health, safety, and general welfare of the
County.
Section 23-12-20. Adoption of Storm Drainage Standards.
A. The Urban Drainage and Flood Control District's "Urban Storm Drainage Criteria
Manual," (UDFCD Manual) consisting of Volume 1, Volume 2, and Volume 3, as currently
published or hereafter amended, is hereby adopted by reference, with the amendments
and additions which are set forth herein. All references to "District" or "The District"
within the UDFCD Manual shall be replaced with "Weld County". The provisions of this
Article shall be known as the "Weld County Storm Drainage Criteria." All facilities for
storm water management on properties located within the unincorporated lands of the
County, whether public or private, shall be designed and constructed in accordance with
such criteria, unless a master drainage plan specific to the area of the site has been
approved by the County. The Weld County Storm Drainage Criteria shall be available
on the Weld County Planning Department's Website.
B. The criteria and procedures contained in this Article XII are intended to supplement the
UDFCD Manual in ways specific to Weld County. In the case of a conflict between the
UDFCD Manual and the supplemental criteria and procedures in this Article XII, such
supplemental criteria and procedures shall take precedence over the UDFCD Manual.
PAGE 2 2015-2623
ORD2015-11
Section 23 - 12 -30 . Drainage Policy .
A . The Policy of Weld County shall be to pursue a jurisdictionally unified drainage effort to
assure an integrated drainage system and to cooperate with other regional and local
planning agencies on drainage matters .
B . For new development , the Policy of Weld County is to prohibit un -detained discharges to
roadside ditches located in the County right-of-way unless granted by a variance .g y
C . Except as set forth below , the Policy of Weld County shall be to require regional and/or
on -site detention for all future developments . Temporary or interim detention/retention
may be required if the downstream regional facilities have not yet been constructed per
the applicable master plan for that location . Stormwater retention facilities are normally
not allowed in Weld County , but will be considered for special circumstances .
D . The Policy of Weld County is to require detention of runoff from the 1 - hour, 100-year ,
storm falling on the developed site and release of the detained water at the historic
runoff rate of the 1 -hour, 5-year storm falling on the undeveloped site for URBANIZING
areas and the historic runoff rate of the 1 - hour, 10-year storm falling on the undeveloped
site for NON - URBANIZING areas . Historic is defined as an undeveloped site with a
2 . 0% imperviousness . If the urbanizing jurisdiction has adopted a different historic
runoff rate than that stated in this subsection , then the urbanizing jurisdiction runoff rate
shall apply .
E . Weld County will not accept any detention or retention pond that does not drain in less
than 72 hours , causes injury to water rights , or is in violation of state or federal law .
Upon evaluation , improvements may be necessary to downstream capacity .
F . Exceptions to stormwater detention shall not jeopardize the public health , safety , and
welfare of public and private property and shall be limited to the following :
1 . No stormwater detention will be required for sites that meet any of the following
conditions . Requirements of the Municipal Separate Storm Sewer System ( MS4 )
areas remain applicable .
a . Use by Right or Accessory Use in the A (Agricultural ) Zone District .
b . Zoning Permits in the A (Agricultural ) Zone District .
c . A second dwelling permit in the A (Agricultural ) Zone District .
d . Towers including , but not limited to , cell , wind , and telecommunication towers .
e . Pipelines or transmission lines .
f. Gravel pits if the stormwater drains into the gravel pit .
g . Residential developments where all the following conditions exist :
1 . Nine ( 9) lots or fewer .
2 . The average lot size is equal to , or greater than , three ( 3 ) acres per lot .
3 . Downstream roadway criteria are not exceeded .
PAGE 3 2015-2623
ORD2015- 11
4 . The total post-development imperviousness for the rural residential
development does not exceed ten percent ( 10 % ) , assuming that all internal
roads and driveways are paved , or will eventually be paved .
h . Development of sites where the change of use does not increase the
imperviousness of the site .
i . URBANIZING areas where the total project stormwater runoff of less than , or
equal to , 5 cubic feet per second ( cfs ) for the 1 - hour , 100-year , storm event .
j . NON - URBANIZING areas where the total project stormwater runoff of less than ,
or equal to , 10 cfs for the 1 - hour , 100-year , storm event .
k . Parcels with total area less than , or equal to , a 1 . 0 gross acre .
I . Individual parcel with an unobstructed flow path and no other parcel ( s ) between
the Federal Emergency Management Administration ( FEMA) regulatory
floodplain channel and the project .
m . A parcel greater than 1 gross acre and less than , or equal to , 5 gross acres in
size is allowed a onetime exception for a new 1 , 000 sq ft building or equivalent
imperviousness .
n . A parcel greater than 5 gross acres in size is allowed a onetime exception for a
new 2 , 000 sq ft building or equivalent imperviousness .
o . Approved by a variance .
Section 23-12 -40 . Rainfall .
The designer shall use the most appropriate and best available data for the project area in
determining the rainfall quantities .
Section 23 -12 -50 . Runoff.
A . The Rational Method should not be used to determine runoff for basins larger than 160
acres . In areas located in the southwest portion of Weld County and where areas are
larger than 160 acres that have drainage characteristics similar to an urban area , the
Colorado Urban Hydrograph Procedure (CUHP ) is an acceptable model for determining
runoff amounts . The CUHP model can be used for basins from 0 to 3 , 000 acres . The
parameter adjustments provided in the runoff chapter of the UDFCD Manual (Volume 1 )
should be used when dealing with basins that are larger than 160 acres .
B . The CUHP model is not applicable in non - urban areas , including those areas in Weld
County that are outside of the Denver Metropolitan area . The U . S . Army Corps of
Engineers ( USACE ) HEC- HMS model is more applicable for mixed suburban -agricultural
areas . The HEC- HMS model can be used on watersheds and drainage basins larger than
160 acres provided the modeling follows the parameters in the HEC- HMS User' s Manual ,
the HEC - HMS Technical Reference Manual , and the HEC - HMS Application ' s Guide .
C . Weld County in its discretion may accept other methodologies as deemed appropriate by
the design engineer.
PAGE 4 2015-2623
ORD2015- 11
Section 23-12-60. Street Drainage.
A. Design Depth Criteria.
1. The primary design objective is to keep the encroachment of stormwater on the street
or road below an acceptable limit for a given flood return period. When stormwater
collects on a street and flows down a gutter or swale, the stormwater encroaches into
the roadway. If left unchecked, the encroachment will hinder traffic flow and may
become hazardous. The maximum encroachment depth is outlined in the table below:
Road Encroachment
Minor Major
Road Design Design Max Encroachment
Classification Storm Max Encroachment Storm
over crown
Local 10 yr May spread to crown 100 yr 18"
Collector 25 yr Leave one lane open 100 yr 12"
Arterial 50 yr No encroachment in lanes 100 yr 0"
B. Inlets.
1. The design guidelines provided in the streets/inlets/storm sewers chapter of the
UDFCD Manual (Volume 1) should be used when designing stormwater inlets. The
standard inlets permitted for use in Weld County streets are shown in the following
table:
Inlet type permitted (CDOT Types)
Curb opening inlet Type R All street types with 6 inch vertical curb
Grated inlet Type C All streets with a roadside ditch or swale
Grated inlet Type 13 Alley or private drives with a valley gutter
Combination inlet Type 13 All street types with 6 inch vertical curb
PAGE 5 2015-2623
ORD2015-11
2. In order to account for factors which decrease the capacity of the inlets—such as
debris plugging, pavement overlaying, and variations in design assumptions—the
theoretical capacity calculated for inlets is to be reduced by the factors presented in
the following table for standard inlets in Weld County.
Percent of
Condition Inlet Type Theoretical Capacity
Allowed
Sump or continuous grade CDOT Type R
5 ft length 88
10 ft length 92
15 ft length 95
Continuous grade Combination Type 13 66
Sump Grated Type C 50
Grated Type 13 50
Combination Type 13 65
C. Pipes.
1. The design guidelines provided in the streets/inlets/storm sewers chapter of the
UDFCD Manual (Volume 1) should be used when designing stormwater pipes.
2. The Department of Public Works should be contacted to determine which types of
storm sewer pipes are permissible for use in public rights-of-way or public drainage
easements.
Section 23-12-70. Major Drainage.
A. Design Flows.
1. The major drainage system must be able to convey the fully developed flow from a
watershed for the 1-hour, 100-year event without significant damage to the system.
B. Open Channel Design Principles.
1. Grass-lined open channels conveying less than 50 cfs may reduce the minimum
1.0-foot freeboard requirement to the freeboard required to convey 1.33 times the
24-hour, 100-year design flow. The reduced freeboard may only occur if a 1.0-foot
minimum freeboard is not physically possible and a variance request is submitted.
PAGE 6 2015-2623
ORD2015-11
2. Maximum side slopes may be as steep as 3H:1V. However, the design engineer
should address how the channels will be maintained since it may not be safe to mow
on slopes that are greater than 4H:1 V.
Section 23-12-80. Culverts.
A. Sizing.
1. The Department of Public Works should be contacted to determine which types of
storm sewer pipes are permissible for use in public rights-of-way or public drainage
easements.
2. Culverts must be designed to the following maximum headwater to depth HW/D
requirements.
Design Storm HW/D
10 Yr 1.0
100 Yr 1.5
B. Materials.
Culverts that are to be installed in a public right-of-way that is routinely burned must be
made of either concrete or metal. Plastic pipes will not be allowed in public rights-of-way
that are subject to weed burning.
Section 23-12-90. Storage.
A. Detention Criteria.
1. Detention ponds shall be sized to store the stormwater runoff generated by the
1-hour, 100-year storm falling on the developed site and release of the detained
water at the historic runoff rate of the 1-hour, 5-year storm falling on the undeveloped
site for URBANIZING areas and the historic runoff rate of the 1-hour, 10-year storm
falling on the undeveloped site for NON-URBANIZING areas. Historic is defined as
an undeveloped site with a 2.0% imperviousness.
2. The detention pond must include volume for the water quality capture volume. Water
quality capture volume may be included as a portion of the total 100-year detention
pond volume.
3. Off-site flows can be routed as follows:
a. Over the spillway; or
b. Routed around the site.
4. The elevation of the top of the detention pond embankment, except at the spillway,
must be a minimum of 1-foot above the 100-year water surface elevation in the
detention pond.
PAGE 7 2015-2623
ORD2015-11
5. There should be no more than two levels of controls, in addition to the water quality
capture volume controls, for detention ponds. Outlet works should be sized and
structurally designed to release at no more than the 1-hour, 5-year historic release
rate in URBANIZING and 1-hour, 10-year historic release rate in NON-URBANIZING
without structural or hydraulic failure. Historic is defined as an undeveloped site with a
2.0% imperviousness. The outlet pipe must contain a minimum of two concrete cutoff
walls embedded a minimum of 18 inches into undisturbed earthen soil. The cutoff
walls must be a minimum of 8 inches thick. The outlet pipe bedding material must
consist of native earthen soil, not granular bedding material, to at least the first
downstream manhole or daylight point.
6. Each detention pond shall contain an emergency spillway capable of conveying the
peak 100-year storm discharge draining into the detention pond. The invert of the
emergency spillway must be equal to, or above, the 100-year water surface
elevation. The depth of flow out of the emergency spillway shall be less than 6
inches. The spillway must have effective erosion protection. In order to protect the
emergency spillway from catastrophic erosion failure, buried riprap shall be placed
from the emergency spillway downhill to the embankment toe of slope and covered
with 6 inches of topsoil. The riprap must be sized at the time of final engineering
design. Grouting of the riprap may be required.
7. In order to prevent damage to publicly-owned infrastructure (roads, roadside
ditches), a concrete cutoff wall 8 inches thick, 3 feet deep, and extending a minimum
of 5 feet into the embankment on each side of the emergency spillway opening, is
required on all privately-maintained detention ponds and required on all regional
detention ponds. The concrete cutoff wall permanently defines the emergency
spillway opening. The emergency spillway elevation must be tied back into the top
of the embankment using a maximum slope of 4:1.
8. The design of the detention facility must provide evidence that the pond will drain in
less than 72 hours. A detention pond that does not drain in less than 72 hours, can
cause injury to water rights, or is in violation of State or Federal law will not be
accepted.
B. Retention Criteria.
1. Retention facilities are not allowed in Weld County without the issuance of a
variance.
2. Retention facilities must be designed to contain 1.5 times the volume of the runoff
generated by the 24-hour, 100-year storm, plus 1 foot of freeboard.
3. The design of the retention facility must include an emergency spillway and must
show that a spill will not adversely impact downstream properties or residences. The
spillway must be designed in accordance with the detention pond spillway
requirements.
4. The design of the retention facility must provide evidence that the pond will drain
through the bottom (sides slopes cannot be used in calculation) in less than 72
hours. A retention pond that does not drain in less than 72 hours, can cause injury to
water rights, or is in violation of state or federal law will not be accepted.
PAGE 8 2015-2623
ORD2015-11
C. Erosion Protection Design Criteria.
Erosion protection for storage facilities needs to be designed to ensure that the
sediment does not leave the site or impact downstream properties. It may be necessary
to install straw bales, riprap, erosion control logs, erosion control blankets, etc. on the
storage facility side slopes to ensure that erosion does not occur until the reseeded
vegetation is established. The Best Management Practices outlined in the UDFCD
Manual (Volume 3) should be used.
Section 23-12-100. Revegetation.
A. Weld County utilizes the information provided in the Revegetation Chapter of the
UDFCD Manual (Volume 2), and the Best Management Practices Chapter of the
UDFCD Manual (Volume 3). Weld County has seed mixes that are applicable to areas
of the County that are highly recommended. These seed mixes can be found under the
Weld County Public Works Website, Weed Management Section. If noxious weeds, as
listed in Weld County Code Chapter 15, exist on-site, the appropriate steps need to be
taken before, during, and after work is completed to control their spread.
B. Seeding and Planting.
In addition to the site preparation guidelines outlined in the revegetation chapter of the
UDFCD Manual (Volume 2), if mulching with straw, the straw must be free of seeds and
weeds.
Section 23-12-110. Stormwater Quality.
A. A water quality feature is intended to improve water quality from the impacts of site
development. A water quality feature can be an existing low spot on the property that
currently collects water or an excavated area. The size required is based upon site
imperviousness. This depression is intended to allow stormwater runoff from the site to
collect and settle out any contaminants prior to flowing offsite to neighboring properties
or downstream waterways.
B. An accepted methodology for a water quality feature design can be found in the UDFCD
Manual, Volume 3, Best Management Practices.
Section 23-12-120. Best Management Practices.
Weld County uses the Best Management Practices that are outlined in the UDFCD Manual
(Volume 3) Best Management Practices.
Section 23-12-130. Maintenance.
A. Culverts located outside County-maintained road rights-of-way are not maintained by
Weld County. The owners of those culverts are responsible for their maintenance.
Culverts that are part of a subdivision drainage plan are maintained by the respective
homeowner's association. Those culverts should be maintained and cleaned out
annually, per the drainage report maintenance plan, or on an as-needed basis to ensure
proper drainage of the subdivision.
PAGE 9 2015-2623
ORD2015-11
B. To assist drainage pond owners with maintenance, an operations and maintenance
manual for detention facilities and associated infrastructure must be developed and
included with the final drainage report.
C. The property owner/developer, not Weld County, is responsible for site maintenance
and revegetation.
D. Weld County will require that all submittals include an operations and maintenance
manual for all water quality and detention pond facilities. The operations and
maintenance manuals shall also be distributed to the applicable homeowners'
association and/or business park association (or equivalent). The operations manuals
will include instructions on safe and correct operations, repair and maintenance of all
installed equipment and facilities and recommended inspection schedules.
E. Access must be provided to the drainage facilities for long term maintenance.
Section 23-12-140. Enforcement.
The enforcement of this Article shall be in accordance with Article X of this Chapter.
Section 23-12-150. Stormwater Drainage Criteria Variances.
The following variance procedures are intended to allow additional exceptions to the code
explicitly listed in Section 23-12-30 provided certain requirements are met. Subsection A
below is intended to be a lower cost option which allows anyone to apply for a variance with
or without stamped engineering documentation. Subsection B below is intended to be
used when more detailed analysis and engineering support is required.
A. An applicant may request a variance for their site when conditions do not meet the
drainage exemptions described previously and impacts to the site and offsite properties
are insignificant. Requests will be reviewed by the Planning Director or his/her designee.
No variance will be considered if it may jeopardize the public health, safety, welfare and
public and private property. In order to be granted, the variance request must:
1. Demonstrate that granting of the variance will still adequately protect public health,
safety, and general welfare.
2. Demonstrate there are no adverse impacts, from stormwater runoff, to the public
rights of way and/or offsite properties as a result of the project.
Any engineer's supporting documentation or analysis has to be signed and stamped by
a licensed PE in the state of Colorado.
If the applicant's variance request is denied for not satisfying the above criteria and in
the sole discretion of the planning director or his or her designee, the applicant has the
option to follow the variance request in Subsection B below or appeal the denial to the
Board of Adjustment.
B. The applicant's engineer may request a variance. The variance request shall be
stamped and signed by a professional civil engineer licensed to practice in the State of
PAGE 10 2015-2623
ORD2015-11
Colorado. Requests will be reviewed by the Planning Director or his/her designee. In
order to be granted, the variance request must:
1. Describe the design criteria of the Weld County Code of which a variance is being
requested.
2. Describe the proposed alternative with engineering rationale which supports the
intent of the Weld County Code.
3. Meet the design intent of the Weld County Code.
4. Demonstrate that granting of the variance will still adequately protect public health,
safety, and general welfare.
5. Demonstrate there are no adverse impacts, from stormwater runoff, to the public
rights of way and/or offsite properties as a result of the project.
An applicant can appeal to the Board of Adjustments the Director of Planning Services
decision regarding the variance per Article VI of this chapter.
C. Variance requests, if accepted, are not precedent setting and are based upon specific
site constraints.
BE IT FURTHER ORDAINED by the Board that the Clerk to the Board be, and hereby is,
directed to arrange for Colorado Code Publishing to supplement the Weld County Code with the
amendments contained herein, to coincide with chapters, articles, divisions, sections, and
subsections as they currently exist within said Code; and to resolve any inconsistencies regarding
capitalization, grammar, and numbering or placement of chapters, articles, divisions, sections,
and subsections in said Code.
BE IT FURTHER ORDAINED by the Board, if any section, subsection, paragraph,
sentence, clause, or phrase of this Ordinance is for any reason held or decided to be
unconstitutional, such decision shall not affect the validity of the remaining portions hereof. The
Board of County Commissioners hereby declares that it would have enacted this Ordinance in
each and every section, subsection, paragraph, sentence, clause, and phrase thereof irrespective
of the fact that any one or more sections, subsections, paragraphs, sentences, clauses, or
phrases might be declared to be unconstitutional or invalid.
PAGE 11 2015-2623
ORD2015-11
The above and foregoing Ordinance Number 2015-11 was, on motion duly made and
seconded, adopted by the following vote on the 3rd day of August, A.D., 2015.
BOARD OF COUNTY COMMISSIONERS
WELD COUNTY, COLORADO
ATTEST:
Barbara Kirkmeyer, Chair
Weld County Clerk to the Board
Mike Freeman, Pro-Tern
BY:
Deputy Clerk to the Board EXCUSED
Sean P. Conway
APPROVED AS TO FORM:
Julie A. Cozad
County Attorney
Steve Moreno
Publication: May 20, 2015
First Reading: June 22, 2015
Publication: July 1, 2015, in the Greeley Tribune
Second Reading: July 13, 2015
Publication: July 22, 2015, in the Greeley Tribune
Final Reading: August 3, 2015
Publication: August 12, 2015, in the Greeley Tribune
Effective: August 17, 2015
PAGE 12 2015-2623
ORD2015-11
Hello