City of Golden Stormwater Standards 

Manual 

October 2012 Revised April 2014 

Public Works Department Engineering Division Environmental Services Division 

City of Golden Stormwater Standards Manual 

Summary of Revisions 

April 2014 revision includes the following minor updates:  Add sediment barrier in sed basin detail, Appendix A Update active stormwater inspection form, Appendix C Update periodic stormwater inspection form, Appendix C Revise Stormwater Inspections, Compliance and Enforcement Fact Sheet, Appendix C

October 2012 revision of the City of Golden Stormwater Standards Manual reflects the integration of the City of Golden Stormwater Quality Control Design Guidance Manual and the City’s drainage standards, previously included in the Streets, Sidewalks and Drainage Specifications. 

October 2012 Revised April 2014 

Public Works Department Engineering Division Environmental Services Division http://www.cityofgolden.net/ 

Table of Contents Introduction ...................................................................................................................................... 1

Stormwater Management ......................................................................................................................... 1

Use of Manual ........................................................................................................................................... 1

References ................................................................................................................................................ 1

Stormwater Management: Drainage .................................................................................................. 2

General Requirements............................................................................................................................... 2

Submittals ................................................................................................................................................. 3

Stormwater Management: Pollutants .............................................................................................. 12

General Requirements............................................................................................................................. 12

Submittals ................................................................................................................................................ 13

Best Management Practices for Permanent Stormwater Control ......................................................... 13

Best Management Practices for Construction ........................................................................................ 13

Appendix A Standard Details ..........................................................................................................................

Appendix B Stormwater Infrastructure Certification form .............................................................................

Appendix C Stormwater Permit Application Packet .......................................................................................

Appendix D Revegetation Requirements ........................................................................................................

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Section I. Introduction

A. Stormwater ManagementUrbanization and development affect both the quantity and the quality of stormwater discharged toreceiving waters. Land disturbing activities such as construction expose soil and allow increased erosionand sediment transport. After construction is completed, the increase in impervious areas such asrooftops, parking lots and paved areas decreases the opportunity for stormwater to infiltrate into theground, increasing flow velocity and potential pollutant transport.

B. Use of ManualThe intent of the Stormwater Standards Manual (Manual) is to present design standards for theimplementation and use of Best Management Practices (BMPs) to manage stormwater for the purposesof water quality and flood control. It will be used by city staff when reviewing stormwater managementpractices. Individual methods shall be selected and implemented to best fit the conditions andrequirements of each site.

The Public Works Director, or designee, shall be authorized to make periodic updates and technicalamendments from time to time. Major revisions will be presented to City Council.

C. ReferencesThis Manual outlines methods for the control of stormwater for development and redevelopment. Thereader is referred to specific design criteria presented in the Urban Storm Drainage Criteria Manual(USDCM), volume 3, as amended.

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Section II. Stormwater Management

A. Stormwater Management: Drainage

The impervious areas associated with urbanization have been shown to increase the volume of runoffwhich has led to flooding in increased severity and degradation of water quality. A coordinatedapproach to managing the increased runoff volumes associated with development and redevelopment iscritical to ensuring the safety of citizens and health of our receiving waterways. The intent of thismanual is to provide standards for responsible management of runoff.

1. General Requirementsa. Flood Control

All development that results in a net increase of 10,000 square feet of impervious area shall provideflood control for the increased impervious area runoff. Runoff rates in the developed condition shallbe attenuated and released at historic rates.

b. WQCVBoth the Water Quality Capture Volume (WQCV) and Excess Urban Runoff Volume (EURV) arepermissible options for water quality. In the event that the WQCV is provided it shall be 120% of thecalculated WQCV and shall be in addition to the 100 year volume. EURV shall be included within the100 year volume.

c. Riparian SetbacksNo new development shall be permitted to construct structures or impervious surfaces within 50’ ofa channel designated as a major drainageway as measured from the top of bank. City of GoldenEngineering Division staff will determine top of bank location when not readily apparent.

d. FloodplainThe City of Golden has adopted the International Building Code (IBC) 2009 Appendix G for floodplainregulations. In addition to the requirements set forth in IBC 2009 Appendix G the City shall requirethe following additional requirements of all development within any FEMA designated Floodplain orany flood study or FHAD adopted by the City:

i. The design flood elevation for all new development shall be the Base flood elevation plus one(1) additional foot of freeboard.

ii. Physical map revisions in the City of Golden in which a floodway is delineated shall adhere to ahalf (1/2) foot rise criteria.

iii. Stream alteration activities shall not be constructed unless the project proponent demonstratesthrough a floodway analysis and report, sealed by a Colorado Registered Professional Engineer,that there are no adverse floodway impacts resulting from the project. This requirement onlyapplies on stream reaches with Base Flood Elevations established.

e. Standard DetailsWith the exception of the details provided in Appendix A, the City has adopted the standard detailsapplicable to drainage found in the latest version of the Colorado Department of Transportation

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M & S standards and the details provided in the latest version of the USDCM. In the event that a detail for a type of facility is provided in both documents, the City of Golden Engineering Division will decide which standard detail is applicable.

f. Steep SlopesGrading disturbance shall not occur on slopes over 25%. Properties with areas of greater than 25%slope should place development requiring grading disturbance on the site areas of less than 25%slope. Incidental slopes, including banks along waterways or small abnormalities of less than 100square feet within a lot shall not be counted toward this requirement.

2. Submittalsa. Drainage Report

Drainage reports must be formatted in accordance with the following outline and must contain allthe applicable information listed below:

I. GENERAL LOCATION AND DESCRIPTIONA. Location

1. Vicinity Map: A map showing the project location within the City. The project area shall beshaded; major arterial streets labeled; and major water courses and water bodies shall belabeled

2. Township, range, section, ¼ section3. Local streets within and adjacent to the subdivision with ROW width shown4. Major drainageways, facilities, and easements within or adjacent to the site

B. Description of Property1. Area in acres2. Existing ground cover (type of trees, shrubs, vegetation, general soil conditions, topography,

and slope)3. Major drainageways4. General project description5. Irrigation facilities6. Proposed land use

II. DRAINAGE BASINS AND SUB-BASINSA. Major Basin Description

1. Reference to major drainageway planning studies such as flood hazard delineation reports,major drainageway planning reports, and flood insurance rate maps

2. Major basin drainage characteristics, existing and planned land uses3. Identification of all irrigation facilities within the basin, which will influence or be influenced

by the local drainage designB. Sub-Basin Description

1. Discussion of historic and proposed drainage patterns of the property2. Discussion of offsite drainage flow patterns and impact on development under existing and

fully developed basin conditions

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III. DRAINAGE DESIGN CRITERIAA. Regulations: Discussion of the optional provisions selected or the deviation from the criteria, if

any, and its justificationB. Discussion on implementation of the "Four Step Process" including Runoff Reduction

Practices, Water Quality Capture Volume, Stabilizing Drainageways and Source Control BMPsC. Development Criteria Reference and Constraints

1. Discussion of previous drainage studies (i.e., project master plans) for the site that influenceor are influenced by the drainage design and how the plan will affect drainage design forthe site

2. Discussion of the effects of adjacent drainage studies3. Discussion of the drainage impact of site constraints such as streets, utilities, rapid transit,

existing structures, and development or site planD. Hydrological Criteria

1. Identify design rainfall2. Identify runoff calculation method3. Identify detention discharge and storage calculation method4. Identify design storm recurrence intervals5. Discussion and justification of other assumptions or calculation methods used that are not

referenced by the criteriaE. Hydraulic Criteria

1. Identify various capacity references2. Discussion of other drainage facility design criteria used that are not referenced in the

criteria3. If there are proposed modifications to areas within the 100-year floodplain or floodway, a

"Floodplain Modeling Report" must be submitted4. If there are proposed modifications to a natural drainageway where a 100-year floodplain

has not been designated, a "Floodplain Modeling Study" must be submittedF. Modifications of Criteria

1. Identify provisions by section number for which a modification is requested2. Provide justification for each modification requested

IV. DRAINAGE FACILITY DESIGNA. General Concept

1. Discussion of concept and typical drainage patterns2. Discussion of compliance with off-site runoff considerations3. Discussion of the content of tables, charts, figures, plates, or drawings presented in the

report4. Discussion of anticipated and proposed drainage patterns

B. Specific Details1. Discussion of drainage problems encountered and solutions at specific design points2. Discussion of detention storage and outlet design3. A summary table for each detention storage pond on the site to include:

• Stage-Storage Curve• Stage-Discharge Curve• Detention Pond Volume Required• Detention Pond Volume Provided

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• Water Quality Capture Volume (WQCV)• Water Quality Elevation• Spillway Elevation• Pond Freeboard• Outlet(s) size(s)

4. Discussion of maintenance access5. Discussion of easements and tracts for drainage purposes, including the conditions and

limitations for use6. Discussion of the facilities needed offsite for the conveyance of minor and major flows to

the major drainageway

V. CONCLUSIONSA. Compliance with Standards

1. Compliance with City of Golden Stormwater Standards Manual2. Compliance with any existing Master Drainage Plans3. Compliance with the City's floodplain regulations4. Compliance with applicable State and Federal regulations

B. Drainage Concept1. Effectiveness of drainage design to control damage from storm runoff2. Influence of proposed development on the Master Drainage Plan recommendation(s)

VI. REFERENCESReference all criteria and technical information used

VII. APPENDICESA. Hydrologic Computations

1. Land use assumptions regarding adjacent properties2. Initial and major storm runoff at specific design points3. Historic and fully developed runoff computations at specific design points4. Hydrographs at critical design points5. Time of concentration and runoff coefficients for each basin

B. Hydraulic Computations1. Culvert capacities2. Storm sewer capacity. Allowable models include StormCAD, UDSewer, FlowMaster, and

Extran. Other models will be accepted on a case by case basis upon prior approval from theCity

3. Street flow calculations for the 2-year and 100-year events regarding street encroachment,theoretical capacity, and allowable gutter flow

4. Storm inlet capacity including inlet control rating at connection(s) to storm sewer system5. Open channel design6. Check dam and/or channel drop design7. Detention facility design including area/volume capacity, outlet capacity, soil analysis, and

ground water table elevations8. Downstream/outfall system capacity to the major drainageway system9. Design of erosion protection measures for culverts, and storm sewer outlets

C. Letters of intent to acquire all necessary off-site easementsD. Water quality design calculations

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E. Printed copies of input and output files for all computer models used in the analysis and designF. Digital copies of input and output files for all computer models used in the analysis and design

b. Drainage PlanThe drawings must contain all the applicable information listed below. All drawings shall be preparedby a Colorado Registered Civil Engineer and must be on a reproducible medium of one or moresheets with an outer dimension of twenty-four by thirty-four (24 x 36) inches

The plan set should include the following sheets:a) Vicinity Mapb) Drainage Planc) Floodplain Pland) Grading Plane) Erosion Control Plan

The Drainage Report and associated drawings must include the following information in aggregate: a) The name of the subdivision or projectb) The date of preparation, the scale, and symbol designating true northc) The boundary lines of the subdivision or project, right-of-way lines of streets, easements and

other rights of way, irrigation ditches, detention ponds, watercourses, and lot lines, with accuratebearings and distances

d) Designations of all streets and other rights of way, including dimensions and names of suchstreets

e) The location and dimensions of any easementsf) Existing and proposed contours at two foot intervals. Spot elevations or one foot contours where

two foot contours do not show on the property or where needed to depict the grading. Spotelevations may be needed in critical areas, especially adjacent to existing developed property

g) The location, size, and type of all storm sewersh) The location, size, and type of all inlets, cross pans, manholes, and other storm sewer

appurtenancesi) Profile views for all subsurface drainage facilities showing their size, slope, lengths, design storm

hydraulic grade lines (2-year and 100-year), cover, details of structures or City Standard details,and relationship with existing utilities

j) The location, size, and type of all culverts, including box culvertsk) The location, size, and type of all open channels, including irrigation ditches with profile views

where applicablel) The location, size, and type of all existing utilitiesm) Cross-sectional views of all open channels, including irrigation ditches, trickle channels, spillway

structures, etc. These views must include applicable easement/right-of-way boundaries andwater surface elevations such as the 100-year storm depth, 2-year storm depth, major stormfreeboard, and operating irrigation level

n) Capacity, discharge, outlet structure, spillways, permanent pool water level (if any), and 100-yearhigh water level for all detention ponds, including both the water quality and water quantityelevations. Cross-hatching of the area inundated by the 100-year water surface elevation isrecommended

o) Water surface profiles for all major open channels, or as requiredp) Show the lowest floor elevation (the basement floor elevation or the bottom of the crawl space)

and grade at foundation elevations of all buildings

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q) Spot elevations critical to describe drainage features and their function (e.g., inlets, cross pans,spillways, inlets/outlets of manholes, culverts, and storm sewers)

r) Drainage sub-basin boundaries and concentration points for the developed site clearly delineatedand labeled

s) A summary table of site hydrology, including offsite flows entering the site for the 10-year and100-year design storms, basin numbers, basin areas, runoff coefficients, and onsite flows for the10-year and 100-year design storms at the concentration points

t) A summary table for each detention pond on the site to include:• Stage-Storage Curve• Stage-Discharge Curve• Detention pond volume required• Detention pond volume provided• Water Quality Capture Volume (WQCV)• Water Quality Elevation• Spillway Elevation• Pond Freeboard• Outlet(s) size(s)

u) A vicinity map showing the project location within the city. The project area shall be shaded, andmajor arterial streets labeled. The map shall be a minimum size of 6" x 6", with a scale rangingfrom 1"=1000' to 1"=3000'

v) Letters of intent to acquire all necessary offsite easements shall be included with the submittalw) If SWMM modeling is used, a sub-basin map and a SWMM schematic diagram are required to

depict the sub-basins and conveyance elements represented in the modelx) General notes relating to the design of the drainage features of the development are required on

the utility plan cover sheet. (Additional notes are required by other departments, such asEngineering and Water/Wastewater.) The required drainage notes are as follows:

1) All street, sanitary sewer, storm sewer and water construction shall conform to CityStandards and Specifications current at date of execution of the Development Agreementpertaining to this development. Any construction occurring three years after the execution ofthe development agreement shall require re-examination of the plans by the Director whomay require that they be made to conform to standards and specifications current at thattime.

2) The type, size, location, and number of all known underground utilities are approximate asshown on the drawings. It shall be the responsibility of the contractor to verify the existenceand location of all underground utilities along the route of the work. Before commencingnew construction, the contractor shall be responsible for locating unknown undergroundutilities.

3) These plans have been reviewed by the City for concept only. The review does not implyresponsibility by the reviewing department, the City Engineer, or the City for accuracy orcorrectness of the calculations. Furthermore, the review does not imply that the quantities ofthe items on the plans are the final quantities required. The review shall not be construed inany reason as acceptance of financial responsibility by the City for additional quantities ofitems shown that may be required during the construction phase.

4) Maintenance of onsite drainage facilities shall be the responsibility of the property owners.

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5) If fill or dredged material is discharged into waters of the United States, a USACE 404 permitis required.

6) If construction affects any Colorado Highway, a Colorado Department of TransportationRight‐of‐Way permit is required.

c. Drainage CertificationAfter construction is complete and prior to final inspection by the City the design engineer (or aProfessional Engineer registered in the state of Colorado) shall submit, to the City of Golden PublicWorks Department, Engineering Division, a signed and sealed certification of the constructed stormfacilities.  The certification shall include a statement that the constructed facilities are inconformance with the approved drainage plan(s). The certification shall also include the “asdesigned” and “as constructed”: WQCV or EURV 10 year orifice elevation Top of pond outlet elevation 100 year restriction plate orientation Total Pond Volume

Overflow elevation width and depth Trickle channel longitudinal slope Trickle channel cross section

d. Stormwater Infrastructure CertificationAfter drainage facility construction is complete and prior to final inspection by the City, thecontractor shall submit to the City of Golden Public Works Department, Engineering Division a set ofred‐line plans or as‐builts showing any deviations from the approved plans, a video inspection of allinstalled pipes and a completed Stormwater Infrastructure Certification.  The Certification form canbe found in Appendix B.

e. Runoff CalculationBoth the Colorado Urban Hydrograph Procedure (CUHP) and the Rational Method are allowablemethods for runoff calculation within the watershed size limitations in the following table.

Applicability of Hydrologic Methods Watershed Size (acres) 

Is the Rational Method Applicable? 

Is CUHP Applicable? 

0 to 5  Yes  Yes (1) 

6 to 90  Yes  Yes (1) 

91 to 160  Yes  Yes 

161 to 3,000  No  Yes (2) 

Greater than 3,000  No  Yes if subdivided into smaller catchments(2) 

(1) If one‐minute unit hydrograph is used.

2) Subdividing into smaller sub‐catchments and routing the resultant hydrographs using SWMM may be needed toaccurately model a catchment with areas of different soil types or percentages of imperviousness.

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Detailed information on both the Rational Method and the Colorado Urban Hydrograph Procedure can be found in the Urban Storm Drainage Criteria Manual (USDCM) Volume 1.

f. ConveyanceStreets are an integral part of the urban drainage system and may be used for transporting stormrunoff up to design limits. The design engineer should recognize that the primary purpose of streetsis for traffic, and therefore the use of streets for storm runoff must be restricted. The policy of theCity is to allow the use of streets for drainage within the limitations described in the followingtables, subject to City approval.

Allowable Use of Streets for MINOR Storm Runoff Street Functional Classification Maximum Theoretical Depth

Local street No curb overtopping. Flow may spread to crown of street. Flow may spread to back of sidewalk for a 4-inch combo curb/sidewalk.

Collector street No curb overtopping. Flow spread must leave at least one 10-foot lane free of water, 5 feet either side of street crown.

Arterial street No curb overtopping. Flow spread must leave at least two 10-foot lanes free of water, 10 feet either side of street crown or median.

Allowable Use of Streets for MAJOR Storm Runoff Street Functional Classification Maximum Theoretical Depth

Local street and collector street Residential dwellings, public, commercial and industrial buildings shall not be inundated at the ground line. The depth of water at the gutter flow line shall not exceed 12 inches.

Arterial street Residential dwellings, public, commercial and industrial buildings shall not be inundated at the ground line. To allow for emergency vehicles, the depth of water shall not exceed 6-inches at the street crown and 12 inches at the gutterflow line, whichever is more restrictive.

g. Storm sewersStorm sewers are a part of the drainage system and are required when the other parts of the systemno longer have capacity for additional runoff. Except as modified herein, the design of storm sewersshall be in accordance with the Storm Sewer section of the STREETS/INLETS/STORM SEWERS chapterof the USDCM.

All new or reconstructed storm sewers shall be sized to convey the major event (100 year) flows inexcess of the allowable street conveyance capacity.

All direction changes, both horizontal and vertical, shall be achieved through a manhole. Bends,longitudinal bending and joint deflection are prohibited.

Contractor shall submit to the City, for approval, shop drawings for all pipe and fittings.

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Polyvinyl Chloride (PVC), High Density Polyethylene (HDPE) and Reinforced Concrete Pipe (RCP) are the only permissible pipe materials for stormwater sewer installations in the City of Golden. All pipes shall meet the material and handling specifications set forth by the Urban Drainage and Flood Control District. UDFCD specifications can be found at the websites listed below:

PVC http://udfcd.org/wp-content/uploads/uploads/resources/specifications/Division%2033%20-%20Utilities/33_41_03_Polyvinyl_Chloride_Pipe.pdf

HDPE http://udfcd.org/wp-content/uploads/uploads/resources/specifications/Division%2033%20-%20Utilities/33_41_01_High-Density_Polyethylene_Pipe.pdf

RCP http://udfcd.org/wp-content/uploads/uploads/resources/specifications/Division%2033%20-%20Utilities/33_41_00_Reinforced_Concrete_Pipe.pdf

h. Best Management Practices (BMPs)The following BMPs should be evaluated for development and redevelopment with consideration ofpollutant removal, flood attenuation and long-term maintenance given site conditions and land use.For specific design criteria for the accepted BMPs listed below, refer to the most current version ofthe USDCM Vol. 3, Chapter 4, "Treatment BMPs" found athttp://udfcd.org/wp-content/uploads/uploads/vol3%20criteria%20manual/04_Chapter_4_Treatment_BMPs.pdf. Where more specific criteria are warranted, it isnoted below: Grass Swale Grass Buffer Bioretention/Rain Garden/Porous Landscape Detention Green Roof Extended Detention Basin: Both the WQCV and full spectrum EURV are permissible options for

water quality. In the event that the WQCV is provided it shall be 120% of the calculated WQCVand shall be in addition to the 100 year volume. EURV shall be included within the 100 yearvolume.

Sand Filter Retention Pond Constructed Wetland Pond Constructed Wetland Channel Permeable Pavements Underground BMPs

o Detention Vaults are prohibited in areas not within a designated Urban Renewal District.Vaults allowed to be installed within an Urban Renewal Area must meet the following:− single chamber− constructed of concrete− have a sloped bottom− be constructed with adequate access to facilitate safe maintenance− must have separate upstream water quality BMPs

o Underground Water Quality BMPs may be allowed for water quality purposes only, providedthat they meet the USDCM removal rates and test data is available for semi arid climates.Further, the maintenance procedures of any permitted proprietary BMPs must meet therequirements of City of Golden Engineering Division.

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The City of Golden encourages the innovative use and application of measures to control stormwater. As with any field of technology, methods and applications of BMPs designed to control stormwater are expected to grow, improve and change. Owners of land undergoing development or significant redevelopment are encouraged to utilize the best available technology. Updates to this Manual will be used periodically to reflect major changes in methodology or application of BMPs or other control measures.

i. Operation and MaintenanceAn important part of all storm drainage facilities is the continued maintenance of the facilities toensure they will function as designed.

Inspection access and maintenance access must be provided to all storm drainage facilities to ensurewater quality and continuous operational capability of the system. Said access shall be granted viaeasement, on the plat, or by other instrument to the City. The property owner shall be responsiblefor the maintenance of all drainage facilities including, but not limited to, inlets, pipes, channels,ditches, hydraulic structures, and detention basins located on their lands unless modified by thesubdivision improvements agreement.

j. Right to EnterTo ensure the public health, safety and welfare, the City shall have the right to enter said property

for the purposes of inspection, operation and/or maintenance of the storm drainage facilities.Should a property owner fail to adequately maintain and/or operate storm drainage facilities, andafter sufficient notice is provided by the City, the City may perform maintenance. All suchmaintenance costs incurred by the City will be assessed to the property owner.

k. EasementsThe easements required to provide adequate inspection, operation and/or maintenance access areas follows:

Facility Type Minimum Easement Width Single pipe 20’ minimum width. Pipe centered in easement. An additional 2’ width

for every 1’ of depth over 5’ as measured from invert. Multiple pipes 10’ minimum on either side from outside edge of pipe(s). Additional 1’ of

width on either side of pipe(s) for every 1’ of depth over 5’ as measured from invert.

Open channels & swales Q100 < 20 cfs: 20 feet Q100 <100cfs: 25 feet Q100 >101cfs: see USDCM vol.1

Detention basins Sufficient to contain storage, freeboard, release structures, and associated facilities, plus no less than 10 feet for inspection and maintenance access around the entire perimeter. For multiple lots, a dedicated tract of land is required.

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Section II. Stormwater Management cont.

B. Stormwater Management: Pollutants - Sources and Controls

Commonly recognized pollutants in urban stormwater runoff include sediment, nutrients, pathogens,road salts, hydrocarbons, metals, temperature, and volume. Structural and Non-structural BMPs areused to prevent, reduce and/or remove pollutants in stormwater flows and/or maintain/restorehydrologic conditions. This Manual provides design criteria to minimize pollutants and reduce impactsto stormwater quality that occur during construction, and provide long-term stormwater management.

l. General Requirementsa. Water Quality

Permanent water quality control to minimize pollutants is required for any activity resulting in,or contributing to, a total disturbed area greater than one half (½) acre and areas less than onehalf (½) acre which are part of a Common Plan of Development or Sale. This requirement maynot apply when:

i. land disturbance to undeveloped land that will remain undeveloped following disturbanceand will be reclaimed in accordance with the City of Golden Revegetation Requirements.

ii. disturbance is associated with road rehabilitation that does not increase the imperviousfootprint.

b. Design StandardsStormwater quality measures shall be integrated into the design. Where open space areas arerequired the design must allow, at a minimum, the first inch of stormwater runoff to travelthrough swales, rain gardens, or other permeable surfaces. All measures shall be designed topromote water quality of stormwater run-off through the use of BMPs.

c. Stormwater Quality PermitA Stormwater Quality Permit is required for any activity resulting in, or contributing to, a totaldisturbed area greater than one half (½) acre and areas less than one half (½) acre which are apart of a Common Plan of Development or Sale.A State Permit for Stormwater Discharges Associated with Construction Activities is requiredonly if more than five acres will be disturbed. The City is a designated Qualifying Local Programby the Colorado Department of Public Health and Environment Water Quality Control Division.Construction sites less than five (5) acres are automatically covered under the State’sStormwater Permit for Construction Activities with a City permit. Sites greater than five (5)acres require a State Stormwater Construction Permit in addition to the City permit. ContactCDPHE at https://www.colorado.gov/pacific/cdphe/wq-construction-permits or303-692-3500 for more information.

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2. Submittalsa. Stormwater Quality Permit Application

A Permittee must be designated on the permit. The Permittee must be an individual personwho will be the responsible party for the project. Authorized agent(s) are typically site personnelwho can ensure quick response to BMP repairs and/or failures.

b. Stormwater Management PlanPlease refer to the SWMP Fact Sheet in Appendix A for plan requirements.

c. Performance SecurityThe Performance Security must be a check or an irrevocable letter of credit. The amount isbased on the cost of material and installation of all BMPs identified on the SWMP, plus theamount to stabilize the entire proposed disturbed area (seed and mulch).

The Performance Security will only be used in the event that the City has to take correctiveaction. Such action will follow a written request to the Permittee. When the City must utilizethe Performance Security, a 15% administrative fee will be assessed and drawn from thePerformance Security. If the City does not draw from the Performance Security it will bereturned upon final stabilization, plus interest at the rate currently earned by the City. It is theresponsibility of the Permittee to request the release of the Performance Security.

3. Best Management Practices (BMPs) for Permanent Stormwater ControlThe BMPs in Part II.A.2.h. should be evaluated for development and redevelopment with consideration of pollutant removal, flood attenuation and long-term maintenance given site conditions and land use. For specific design criteria for the accepted BMPs, refer to the most current version of the USDCM Vol. 3, Chapter 4, "Treatment BMPs" found at http://udfcd.org/wp-content/uploads/uploads/vol3 criteria manual/04_Chapter_4_Treatment_BMPs.pdf. Where more specific criteria are warranted, it is noted in Part II.A.2.h.

The City of Golden encourages the innovative use and application of measures to control stormwater. As with any field of technology, methods and applications of BMPs designed to control stormwater are expected to grow, improve and change. Owners of land undergoing development or significant redevelopment are encouraged to utilize the best available technology. Updates to this Manual will be used periodically to reflect major changes in methodology or application of BMPs or other control measures.

4. Best Management Practices (BMPs) for ConstructionThe following BMPs should be evaluated for appropriateness with consideration of site conditions and the type of construction, to control erosion and sediment and waste. For specific design criteria and construction details for the accepted BMPs listed below, refer to the most current version of the USDCM Vol. 3, Chapter 7, "Construction BMPs" found at http://udfcd.org/wp-content/uploads/uploads/vol3 criteria manual/Chapter 7 Construction BMPs.pdf. Where more specific criteria are warranted, it is noted below:

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Erosion Controls Sediment Controls Site Management Materials Management Surface Roughening Silt Fence Construction

Sequencing/Phasing Concrete Washout

Temporary and Permanent Seeding (1)

Sediment Control Log Protection of Existing Vegetation

Stockpile Management

Soil Binders Straw Bale Barrier Construction Fence Good Housekeeping Practices

Mulching (1) Rock Sock Vehicle Tracking Control Materials Management

Compost Blanket/Berm

Inlet Protection Stabilized Construction Roadway

Concrete Washout

Rolled Erosion Control Products (1)

Sediment Basin Stabilized Staging Area

Temporary Slope Drain

Sediment Trap Street Sweeping/Vacuuming

Temporary Outlet Protection

Vegetative Buffers Temporary Diversion Channel

Rough Cut Street Control

Chemical Treatment Dewatering Operations

Earth Dikes/Drainage Swales

Temporary Stream Crossing

Terracing Temporary Batch Plant

Check Dams Paving and Grinding Operations

Streambank Stabilization Wind Erosion/Dust Control

(1) Refer to the City of Golden Revegetation Requirements, Appendix D

The City of Golden encourages the innovative use and application of measures to controlstormwater. As with any field of technology, methods and applications of BMPs designed to controlstormwater are expected to grow, improve and change. Owners of land undergoing developmentor significant redevelopment are encouraged to utilize the best available technology. Updates tothis Manual will be used periodically to reflect major changes in methodology or application ofBMPs or other control measures.

15

AppendixA

Standard Details 

Storm Inlet Tie‐in City Storm Manhole Lids Sediment Barrier in Sediment BasinCut Back Curb

STEP 2: AFTER PLACING NEW PIPE, CUT PIPE FLUSH WITH INSIDE OF INLET WALL AND POUR PATCH AND EXTERNAL COLLAR MONOLITHICALLY AGAINST A FORM PLACED ON INSIDE WALL USE #5 REBAR AT FOUR CORNERS OF PATCHED AREA TO COLLAR AND #4 AROUND COLLAR. COLLAR SHALL BE A MINIMUM OF TWELVE (12) INCHES LARGER THAN THE OUTSIDE DIAMETER OF THE NEW STORM PIPE AND A MINIMUM OF SIX (6) INCHES THICK.

,-------7

I #5 + ____ ....._I

I I

+" I I 6" MINI I MIN

I .....__,, I

I \.--,-,.,,�-.,.___J I L�__.':' _____ _J

COLLAR

P'TTERtl, .' llltllllUII €JF EIGIFF (§) lflCIIES i "l'CI i' lll"fl 11!1 fllli' 11)1 IHAM! Iii' t\l 1111

I\IEW PIPE !i'i"ERI f\E i'lfl6/ PIPE c9111 I PF 11

Ml�JIMUM OF TOJ (1 O) l�JCI IES ABOVE Tl IE EXISTl�IC FLOOR OF TFIE l�ILET. CUT MUST BE HWH l�ISILJE TO Po:EVE�IT SPALU�IG OF IMLE I WAI I A DR( Iii ARC ORE E!f;Hi 11,H HES

1 o"

MIN

6" MIN

STEP 3: REPAIR ANY IRREGULARITIES ON INSIDE OF INLET WALL WITH NON-SHRINK GROUT.

DIRECTOR OF PUBLIC WORKS

APPRU? A_ .

CITY EN��

TIE INTO EXISTING INLET WITH NEW STORM PIPE

SCALE: NTS

DEPARTMENT OF PUBLIC WORKS DA TE: FEB 2007

DETAIL NO.

X

L

2" _r[51mm]

3" [76mm]

TOP OF COVER

1" (25mm) LETTERING (RECESSED FLUSH)

LETTERING

1 /2" [13mm] LETTERINGRECESSED

1" (25mm) LETTERINGRECESSED FLUSH

r---- 23[ 6¼� m] IA

---------J I 1 " I I

_1 [25mm]

L 7 1/4" I [184mm1

20 11/16" DIA. [526mm] --------i

SECTION OF COVER

r! 7/8" [22mm]

BOTTOM OF COVER

PICKSLOT DETAIL

...J MACHINED SURFACE

EAST JORDAN IRON WORKS, INC.

P.O. BOX 439 EAST JORDAN, Ml. 49727

1-800-874-4100 FAX 231 -536-4458

DRAWN SMH

APPROVED

DATE 12/03/01

DATE

2405ACOVER

PRODUCT NO.

00240574

CATALOG NO.

2405A

REF. PRODUCT DRAWING

00240573

EST. WT.

COVER: 135 LBS 61kg

OPEN AREA N/A

MAT'L SPEC.

COVER - GRAY IRON ASTM A48 CL35

LOAD RATING

HEAVY DUTY

2x2 STAKES

WASHED ¾" GRAVEL IN WIRE CYLINDER OR SEDIMENT CONTROL LOG (TYP)

BARRIER TO BE IMBEDDED TWO INCHES INTO SOIL

36"

GRAVEL CYLINDER ABUTS AGAINST SIDE OF STRUCTURE

SEDIMENT BARRIER

FOR OUTLET STRUCTURE

CITY OF GOLDEN

SEDIMENT BARRIER

SCALE: NTS

DEPARTMENT OF PUBLIC WORKS DA TE: JUNE 2 006

DETAIL NO.

IP

16 

AppendixB

Stormwater Infrastructure Certification  

Page 1 of 1

CITY OF GOLDEN Stormwater Infrastructure Certification

1465 10TH STREET GOLDEN, CO 80401

JOE PUHR CIVIL ENGINEER

303-384-8115 (FAX) 303-384-8161

TO BE COMPLETED BY DESIGN ENGINEER AND RETURNED PRIOR TO ISSUANCE OF CERTIFICATE OF OCCUPANCY

Property Location Address: Permit Number: Location Description: Parcel Size (acre):

Permanent BMP Type: Check all that apply. Extended Detention Basin Retention Pond Bioretention (PLD, Rain Garden) Grass Swale Grass Buffer Sand Filter Constructed Wetland Pond Green Roof Constructed Wetland Channel Permeable PavementStormwater Collection System: If additional space is needed complete on additional form and attach. Pipe System: Size: Length: Material: Size: Length: Material: Surface System: (gutters, pans, channels, etc...) Width(ft): Depth(ft): Max. Longitudinal Slope(%): Surface Material: Width(ft): Depth(ft): Max. Longitudinal Slope(%): Surface Material: Flood Control: Design 100 Year Volume(CF): Constructed 100 Year Volume(CF): Design 100 Year WSEL: Constructed 100 Year WSEL: Design 10 Year Volume(CF): Constructed 10 Year Volume(CF): Design 10 Year WSEL: Constructed 10 Year WSEL: Water Quality: Design WQCV(CF): Constructed WQCV(CF): Design WQCV WSEL: Constructed WQCV WSEL:

I hereby certify that the stormwater and drainage facilities for the above referenced project have been constructed in conformance with the approved design. Further I certify that any deviation from the design has been documented and approved, in writing, by the City of Golden and that said documentation has been provided to the City of Golden.

Signature: Date:

Affix Professional Engineer Seal

AppendixC

Stormwater Permit Application Packet 

Permit Fact Sheet Fee Schedule Permit Application SWMP Fact Sheet Inspections, Compliance and Enforcement Fact Sheet Inspection Report – active Inspection Report – periodic 

17 

CITY OF GOLDEN Stormwater Quality Permit

Fact Sheet

1445 TENTH STREET GOLDEN, CO 80401

303-384-8188 (FAX) 303-384-8161

Rev Sept 2012

Why is a Stormwater Quality Permit Required? The stormwater program is mandated under the National Pollutant Discharge Elimination System (NPDES), a component of the Clean Water Act. The requirement is intended to reduce the amount of pollutants entering streams, rivers, lakes, and wetlands as a result of runoff from residential, commercial and industrial areas. Large construction sites have been under a requirement to obtain permit coverage since 1992 (Phase I of the program). Small construction sites have been under a requirement to obtain permit coverage since July 1, 2002.

When is a Stormwater Quality Permit Required from the City? A Stormwater Quality Permit is required if you will disturb one half acre or more (≥1/2) OR if you will disturb less than one half acre that is part of a larger common plan of development or sale. A “common plan of development or sale” includes sites where multiple, separate and distinct construction activities may be taking place at different times, on different schedules, or under separate ownership, but under a single plan. This includes, but is not limited to, phased projects with multiple filings or lots, and projects in a contiguous area that may be unrelated but still under the same contract. This also includes development of all lots and parcels within an approved subdivision or Planned Unit Development, regardless of the size of the individual lots or parcels that occurs within the first five years following recordation of the final subdivision plat or Planned Unit Development document.

When is a Stormwater Permit Required from the State? The City is a designated Qualifying Local Program by the Colorado Department of Public Health and Environment Water Quality Control Division. Construction sites less than five acres are automatically covered under the State’s Stormwater General Permit for Construction Activities with a City permit. Sites greater than five acres require a State Stormwater Construction Permit in addition to the City permit. Contact CDPHE at https://www.colorado.gov/pacific/cdphe/wq-construction-permits or 303-692-3500 for more information.

What is Necessary to Obtain a Stormwater Quality Permit? Permit application A Permittee must be designated on the permit. The Permittee must be an individual person

who will be the responsible party for the project. Authorized agent(s) are typically site personnel who can ensurequick response to BMP repairs and/or failures.

Stormwater Management Plan (SWMP) Please refer to the SWMP Fact Sheet for plan requirements. Performance Security Must be a check or an irrevocable letter of credit. The Performance Security is based on the

cost of material and installation of all BMPs called for on the SWMP. The Performance Security will only be used inthe event that the City has to take corrective action. Such action will follow a written request to the Permittee.When the City must utilize the Performance Security a 15% administrative cost will be assessed and drawn from thePerformance Security. If the City does not draw from the Performance Security it will be returned upon finalstabilization, plus interest at the rate currently earned by the City. It is the responsibility of the Permittee torequest the release of the Performance Security.

CITY OF GOLDEN Stormwater Quality Permit

Fee Schedule

1445 TENTH STREET GOLDEN, CO 80401

303-384-8188(FAX) 303-384-8161

Effective January 1, 2010, per City of Golden Resolution 1997, the following fees will be assessed: • Stormwater Quality Permit $350 for initial permit and SWMP review• Stormwater Quality Permit renewal - $125 for annual renewal• Stormwater Quality Permit reinspection fee - $40

The Performance Security is a separate requirement. Please see the Permit Application.

CITY OF GOLDEN Stormwater Quality Permit Application

1445 TENTH STREETGOLDEN, CO 80401

303-384-8188(FAX) 303-384-8161

Permit required for all land disturbances equal to or greater than ½ acre OR if you will disturb less than one half acre that is part of a larger common plan of development or sale.

Project Information Project Name:

Address/Location:

Contact Information

Owner

Name:

Contact Person:

Address:

Phone: Fax:

Mobile: Email:

Contractor

Name:

Contact Person:

Address:

Phone: Fax:

Mobile: Email:

Other

Name:

Contact Person:

Address:

Phone: Fax:

Mobile Email:

Designate a permittee from the above list:

List, in addition to the permittee, site personnel who will have authority to make modifications:

Project Information:

Project Size (acres):

Brief Description of Project:

Project Schedule: (provide further detail with the Stormwater Quality Management Plan)

Expected work start date:

Expected work completion date:

Performance Security:

Stormwater Quality Control Features: (for security escrow calculation) Item description Quantity Unit $/Unit Total

Total Performance Security $

As a condition for the issuance of a stormwater quality permit, applicants shall be required to provide security in the form of cash escrow or an irrevocable letter of credit. The amount of the security shall be based upon the cost of the work required to ensure compliance with the permit’s terms and conditions. The security, with interest at the rate currently earned by the city, less any deductions, shall be released upon the city’s determination that the Permittee has successfully completed all work required by the permit. If the Permittee does not successfully complete all required work or violates any requirement of the permit, the city may take corrective measures and charge the cost of such to the Permittee. Such costs shall include the actual cost of any work deemed necessary by the city plus administrative and inspection costs and penalties pursuant to the city’s stormwater quality enforcement policy. In determining the cost of work, a 15% administrative fee shall be assessed. If the total of such costs exceeds the security, the Permittee shall be responsible for payment of the remaining balance within thirty calendar days of receipt of an accounting of such from the city. It is the Permittee’s responsibility to request a release of the Performance Security. Please note that eligibility for a full release is determined by adequate permanent stormwater quality control features, including established vegetation. In most cases, a minimum of one year from the date of seeding is necessary to determine vegetation establishment.

NOTE: This permit is separate from any permits required by the Colorado Department of Public Health and Environment, Water Quality Control Division under the Colorado Discharge Permit System.

FOR OFFICE USE

Application received:

Stormwater Quality Control Plan received:

Total Performance Security collected: $

Date paid: Method of Payment:

CITY OF GOLDEN Stormwater Management Plan

Fact Sheet

1445 TENTH STREET GOLDEN, CO 80401

303-384-8188 (FAX) 303-384-8161

Rev Sept 2012

A Stormwater Management Plan (SWMP) is required for a City of Golden Stormwater Quality Permit. A SWMP must include a description of all stormwater management controls that will be implemented as part of the construction activity to control pollutants in stormwater discharges. Consult the City of Golden Stormwater Standards Manual for approved practices and details. The Manual can be found at http://www.cityofgolden.net/media/StormwaterStandardsManual.pdf. Refer to the CDPHE Water Quality Control Division for CDPS requirements and a more thorough discussion on preparing a SWMP at https://www.colorado.gov/pacific/sites/default/files/STORMWATER MANAGEMENT PLAN PREPARATION GUIDANCE.pdf.

The SWMP shall be prepared in accordance with good engineering, hydrologic and pollution control practices. The SWMP does not need to be prepared by a registered engineer. The Plan must describe the implementation of Best Management Practices (BMPs) that will be used to reduce the pollutants in stormwater discharges associated with construction activity and post-construction runoff.

The SWMP must be regularly updated and reflect site conditions at all times. Possible modifications may include replacing BMPs, adding BMPs, and identifying additional potential sources of pollution. Hand-written notations, initialed and dated, are adequate for most plan updates.

An efficient record-keeping system is a helpful tool in managing inspection and maintenance reports. It is strongly recommended that a logbook be maintained for inspection reports, maintenance records, spill response, weather conditions, training, correspondence, etc. The documents must be kept on site when construction activities are occurring (site office, trailer, box or truck) and be made available to EPA, State and local inspectors.

SWMP Contents The following should be used as a guide in preparing the SWMP. Each item must be addressed in the SWMP, or referenced in the SWMP if another plan or document containing the information will be used.

1. Stormwater Quality StatementInclude the following statement on the Plan:

Stormwater quality best management practices shall be implemented to minimize soil erosion, sedimentation, increased pollutant loads and changed water flow characteristics resulting from land disturbing activity, to the maximum extent practicable, so as to minimize pollution of receiving waters.

2. Site Descriptiona) A description of the construction activityb) A proposed construction schedulec) Total area of the site, and total disturbed area, including offsite staging/storage areasd) A description of the soil and soil erosion potentiale) A description of the existing vegetation at the site, including coverage

2. Site Description cont.f) The location and description of potential pollution sources. At a minimum, each of the following must

be evaluated and identified in the SWMP if determined to be a potential pollution source:i) Disturbed and stockpiled soil, including dust and contaminated soilii) Vehicle trackingiii) Materials handling and material storageiv) Equipment maintenance and fuelingv) Waste management including concrete washoutvi) Asphalt or concrete batch plants

g) The location and description of any anticipated non-stormwater discharges such as uncontaminatedsprings and landscape irrigation return flows. Note that construction dewatering cannot be dischargedto surface waters or to storm sewer systems without separate CDPS permit coverage.Uncontaminated dewatering water can be discharged to the ground if it is identified in the SWMP withBMPs adequate to control pollutants, and if the discharge does not leave the site as surface runoff.

h) The name of the receiving water(s) and the size, type and location of any outfall or, if the discharge isto a municipal separate storm sewer, the name of the system, the location of the storm sewerdischarge, and the ultimate receiving water(s)

3. Location and description of appropriate control measures (BMPs)The Plan must indicate locations for and descriptions of existing control measures and additional controlmeasures that will be used. Approved details must be included for each BMP indicated. The plan shouldclearly describe the implementation of BMPs relevant to each phase of site development:

a) before clearing and grading begins,b) during all phases of construction (temporary construction BMPs)c) post-construction/final stabilization (permanent BMPs)d) identify staging areas, materials handling and material storage, and spill prevention measures

appropriate to the site

4. Inspection and Maintenance ProceduresThe plan must include inspection and maintenance procedures to ensure BMPs are effective and in goodoperating condition. The following are required minimum procedures:

a) Inspections1) Perform every 14 days, and within 24 hours of a stormwater event that causes surface erosion.

Perform every month on sites where construction is complete, but final stabilization is pending2) During each inspection, observe disturbed areas, the site perimeter, material storage areas, and

BMPs3) Complete an inspection report for each inspection performed4) Keep inspection reports on site

b) Maintenance1) Perform maintenance and repairs as soon as possible on items or areas identified in the inspection

report. Most repairs should be completed within 24 to 48 hours.2) Perform maintenance as indicated in the City of Golden Stormwater Standards Manual, per

manufacturer’s specifications, or other sources determined to be acceptable

rev Apr 2014

Stormwater Quality Construction Site Program Inspections, Compliance and Enforcement

Inspections

The construction site operator is required to perform routine inspections to effectively address maintenance and repair of BMPs. These must be performed every 14 days and within 24 hours of a storm event that causes surface erosion. The construction site operator is encouraged participate in inspections with the City to enable effective communication and quick response to any stormwater quality control deficiencies.

Compliance

Maintenance, repair or installation of BMPs that is noted during the inspection is required to be completed as soon as possible – typically within 24 to 48 hours.

The following outlines typical non-compliance issues and possible enforcement actions. For more detailed information, please refer to Municipal Code chapter 13.30.

Non-Compliance Issues

Failure to obtain a City of Golden Stormwater Quality Permit Failure to obtain a State Stormwater General Permit for Construction Activities if the project is

greater than 5 acres Failure to abide by the conditions of the Stormwater Quality Permit Failure to properly install, maintain, replace and/or remove Failure to implement the Stormwater Management Plan Failure to modify the Stormwater Management Plan to reflect field changes Direct discharge of pollutant(s) to the storm sewer system

Enforcement Actions

If the non-compliance issues are observed during an inspection, the following actions may be taken: Verbal warning Written Compliance Order Revocation of permits Denial of further review or future inspections and/or permits Stop Work Order Hiring a private contractor and/or city crew to perform work – cost of work will be deducted from the

Performance Security

rev Apr 2014

Priority Violations: may result in an immediate issuance of a Stop Work Order. Priority Violations may include: work without a permit; working beyond limits of permitted area; discharge of contaminated water into storm sewer system; washing a roadway; washing concrete trucks in unapproved locations; failure to correct routine violations.

Routine Violations: may result in a written notice detailing non-compliant items and a compliance date. Failure to meet the compliance deadline may result in revocation of permits, denial of further review or future inspections and/or permits, Stop Work Order, or hiring a private contractor and/or city crew to perform the work. Routine Violations may include: failure to abide by the conditions of the Stormwater Quality Permit, and failure to properly install, maintain, replace and/or remove BMPs .

rev Feb 2014

Active Site Stormwater Inspection Report

Project Name: Project Address/Location: Date: Time: Temp: Weather: dry/rain/snow/wind Contact: Inspection by: Inspection type: routine/post-event

Construction Activities Today Planned for This Week Planned for Next Week Grading Excavation Utility Construction Foundations Structural Work Asphalt Paving Landscaping

BMPs To Be

Constructed Good

Condition Requires

Maintenance Needs

Replacement PS Permanent Seed / Sod MU Mulch SR Surface Roughening ECB Erosion Blanket DD Diversion Ditch / Berm CD Check Dams SB Sediment Basin OP Outlet Protection SF Silt Fence SCL Sediment Control Log RS Rock Sock IP Inlet Protection VTC Vehicle Tracking Pad

Street Sweeping CWA Concrete Washout Trash/Waste/Fuel leaks Material Storage/Stockpiles

Required Compliance Action:

rev Feb 2014

Periodic Stormwater Inspection Report

Project Name: Project Address/Location: Contact: Inspection by: Date:

BMPs Adequate Requires Maintenance Requires Immediate Protection

Sod Seed Mulch Erosion Control Blanket Grass Buffer Grass Swale Bioretention Green Roof Extended Detention Basin Sand Filter Retention Pond Constructed Wetland Pond Constructed Wetland Channel Permeable Pavement Other:

Comments:

18

Appendix D

Revegetation Requirements

These requirements are to be used in place of Temporary and Permanent Seeding, Mulching, and Rolled Erosion Control Products included in USDCM vol. 3 as noted in section II.B.4.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

CITY OF GOLDEN REVEGETATION REQUIREMENTS

PART 1 - GENERAL

1.1 Description.

A. This section covers soil preparation, fertilizing, seeding, mulching, installation oferosion control fabrics, watering and initial care, final inspection and approval, andthe guarantee period for temporarily and permanently revegetated areas.

B. This section addresses work within the limits of disturbance as shown on theDrawings. However, if disturbance does occur outside of this designated area, thissection will also pertain to those areas which have been disturbed.

PART 2 - MATERIALS

2.1 Quality.

All materials used for revegetation shall be new and without flaws or defects of any type, and shall be the best of their class and kind.

2.2 Handling and Storage.

Protect all materials used for revegetation from damage, deterioration, or loss of any kind while in transit, storage and during installation.

2.3 Fertilizer.

Commercial product of uniform composition, free flowing and conforming to applicable State and Federal laws. Deliver in original, unopened containers. Application rates shall be based upon recommendations of soils laboratory and shall be reviewed by the CITY. Biosol organic fertilizer is preferred to synthetic fertilizer.

2.4 Herbicide.

Where site conditions warrant or is determined by the CITY, use "Roundup" herbicide as a one percent (1%) application solution or other approved equal that is recommended and legally approved.

2.5 Soil Conditioners.

Where topsoil has been stripped or is absent from the soil horizon, soils conditioners may be required by the CITY. Acceptable organic soil amendment may include mycorrhizal inoculums, humate conditioners or certified Class II compost product produced on a site compliant with and in accordance with current Colorado Department of Health and Environment (CDPHE) regulations pertaining to Solid Waste Composting. Compost shall be a totally organic product that has been aerobically and naturally processed without the addition of coarse wood chips. Organic material shall be tilled to a minimum depth of eight inches (8”) or per manufacturer’s specification. The application of granular humate is acceptable.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

2.6 Temporary Revegetation Seed.

Furnish in bags or containers clearly labeled to show the name and address of the supplier, the seed name, the lot number, net weight, percent of weed seed content and the guaranteed percent of purity and germination. All seed shall be free from noxious weeds as listed in the Colorado Noxious Weed Act; seed shall be fresh, clean, new crop seed. Do not use seed which has become wet, moldy or otherwise damaged in transit or storage.

No. Species Growth Season Pounds of Live Seed/acre

Planting Depth (in)

1. Oats Cool 35 - 50 1 - 2

2. Spring Wheat Cool 25 - 35 1 - 2

3. Spring Barley Cool 25 - 35 1 - 2

4. Annual Ryegrass Cool 10 - 15 ½

5. Millet Warm 3 - 15 ½ - ¾

6. Sudangrass Warm 5 - 10 ½ - ¾

7. Sorghum Warm 5 - 10 ½ - ¾

8. Winter Wheat Cool 20 - 35 1 - 2

9. Winter Barley Cool 20 - 35 1 - 2

10. Winter Rye Cool 20 - 35 1 - 2

11. Triticale Cool 25 - 40 1 - 2

Adapted from Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 - Best Management Practices

Successful seeding of annual grass resulting in adequate plant growth will usually produce enough dead plant material residue to provide protection from wind and water erosion for an additional year. This assumes that the cover is not disturbed or mowed closer than 8 inches.

Hydraulic seeding may be substituted for drilling only where slopes are steeper than 3:1 or where access limitations exist.

Seeding rates should be doubled if seed is broadcast; or increased by 50 percent if done by a Brillion drill or by hydraulic seeding.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

2.7 Permanent Revegetation Seed.

A. Furnish in bags or containers clearly labeled to show the name and address of thesupplier, the seed name, the lot number, net weight, percent of weed seed contentand the guaranteed percent of purity and germination.

B. All seed shall be free from noxious weeds as listed in the Colorado Noxious WeedAct; seed shall be fresh, clean, new crop seed. Do not use seed which has becomewet, moldy or otherwise damaged in transit or storage.

C. The seed shall be mixed in proportions, generally matching the followingrecommended mix designs of the indicated manufacturer’s (or approved equals), asindicated and as necessary to obtain the application rate specified.

D. The following mixes are preferred. The City will review alternatives for approval.

1. Rocky Mountain Native Mix from Arkansas Valley Seeds

Common Name Variety Percent Lbs/Acre

Slender Wheatgrass Revenue 25

Mountain Brome Bromar 20

Blue Grama Hachita 20

Idaho Fescue Winchester 15

Buffalograss Bison 10

Green Needlegrass Lodorm 5

Indian Ricegrass Paloma 5

Total 100% 20

Hydraulic seeding may be substituted for drilling only where slopes are steeper than 3:1 or where access limitations exist.

Seeding rates should be doubled if seed is broadcast; or increased by 50 percent if done by a Brillion drill or by hydraulic seeding.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

2. Foothills Native Mix from Pawnee Buttes Seed

Common Name Variety Percent Lbs/Acre

Indian Ricegrass Paloma 10

Little Bluestem Camper 10

Blue Grama Hachita 10

Indiangrass Cheyenne 10

Sandberg Bluegrass High Plains 10 Rocky Mountain

Fescue Native 10

Sideoats Gramma Butte 10

Green Needlegrass Lodorm 10

Big Bluestem Roundtree 8

Sand Dropseed Reliable 2

Western Wheatgrass Arriba 10

Total 100% 25

3. Short Grass Prairie Mix from Western Native Seed

Common Name Variety Percent Lbs/Acre

Buffalograss Bison 40

Western Wheatgrass Arriba 30

Blue Grama Hachita 24

Galleta Grass Viva 3

Sand Dropseed Reliable 1.5

Needle & Thread Native 1.5

Total 100% 20

CITY OF GOLDEN REVEGETATION REQUIREMENTS

4. Mix for Detention Ponds.

Common Name Variety Percent Lbs/Acre

Buffalograss Texoka 4 9.0

Blue Grama Hachita 39 6.0

Switchgrass Blackwell 18 6.0

Western Wheatgrass Barton 4 5.0

Sand Dropseed Reliable 14 1.0

Inland Saltgrass Native 14 3.0

Prairie Cordgrass Native 7 5.0

Total 100% 35.0

Where there is persistent water, add the following:

Common Name Variety Percent Ozs/Acre

Wooly Sedge Native 1.4 4.0

Nebraska Sedge Native 2.3 4.0

Baltic Rush Native 53.1 4.0

Louisiana Sage Artemsia ludoviciana 19.4 1.0

Aster Native 5.2 3.0

Showy Milkweed Asclepias speciosa 0.3 2.0

Swamp Milkweed Asclepias incarnata 0.3 2.0

Wild Bergamot Monarda fistulosa 6.0 3.0

Yarrow Achillea millefolium 12.0 1.0

Total 100% 24.0

CITY OF GOLDEN REVEGETATION REQUIREMENTS

5. Invasive, Exotic Grasses to AVOID for Revegetation

Common Name Species Comments

Canada Bluegrass Poa compressa

Creeping Bentgrass Agrostis stolonifera

Extensively rhizomotous, highly competitive with native species

Crested Wheatgrass Agropyron desertorum Forms monoculture

Hard or Sheep Fescue Festuca ovina

Intermediate Wheatgrass

Agropyron intermedium Outcompetes native species

Kentucky Bluegrass Poa pratensis

Meadow Fescue Festuca pratensis

Meadow Foxtail Alopecurus pratensis

Orchardgrass Dactylis glomerata

Quackgrass Agropyron repensVery aggressive, highly competitive with native species

Reed Canary Grass Phalaris arundinacea

Replaces native species in riparian areas

Ryegrass: Italian, annual ryegrass, common rye

Loluim perenne

Smooth Brome Bromopsis inermis Outcompetes native species

Tall Fescue Festuca arundinacea

Timothy Phleum pratense

Adapted from the Colorado Native Plant Society, 2002

The plants listed above are invasive, exotic species which threaten or potentially threaten natural areas, agricultural lands, and gardens. While there are thousands of introduced plants which pose no threat, there are some that become invasive, displacing and outcompeting native vegetation.

2.8 Mulch.

A. Mulch shall be clean, weed-and seed-free, long stemmed grass hay (preferred) orcereal grain straw. Mulch should be applied evenly at a rate of two tons per acre. Atleast fifty percent (50%) of the mulch, by weight, should be ten inches or more inlength. For steep slopes (slopes steeper than 3:1), drainage swales, in areas ofanticipated heavy runoff, and other special situations, blankets anchored withstaples, are required instead of mulch.

B. Hydromulch: Degradable green dyed virgin wood cellulose fiber, free from weeds orother foreign matter toxic to seed germination. Apply product according to

CITY OF GOLDEN REVEGETATION REQUIREMENTS

manufacturer's specifications at a minimum rate of two thousand (2,000) pounds/acre.

C. Compost Blanket: The use of a Class I Compost Blanket is an acceptable alternativeto crimped mulch for stabilizing exposed soils, but shall not be used in drainagewaysor concentrated flow areas.

2.9 Organic Tackifier/Binder.

A. All mulched areas shall receive an application of an organic mulch tackifier/binder.Use a non-toxic, non-corrosive, all organic powder which forms a firm resilient, re-wettable membrane.

B. Manufacturers:

a. Regular application: Nilex Plantango Insul-ari, or approved equal, at two hundred(200) pounds per acre.

b. Steep (3:1 or greater) slopes or unstable soil: Rantec Guardian Tackifier, orapproved equal, at one-hundred twenty (120) pounds per acre.

2.10 Erosion Control Blanket.

A. An erosion control blanket shall be used on slopes equal to or steeper than three toone (3:1) and in swale bottoms or in areas of concentrated flows (i.e. detention pondlow flow areas, inlets, and outlets), except where sod is used. Biodegradable nettingmust be used.

B. Manufacturers:

1. Slope Application: Type SC 150 BN, North American Green, or approved equal.

2. Areas receiving flows: Type C 125 BN, North American Green, or approvedequal.

2.11 Water.

The CONTRACTOR will be required to provide all water necessary for hydraulic spray applications. The City bulk water sales station is located on the north end of Golden at 1151Catamount Drive, adjacent to the City of Golden maintenance shops. This station provides bulk water to contractors without the need for the customer to rent a hydrant meter. A standard 2.5" male fire hose connection is installed on the station. The discharge from the station is currently set at approximately 250 gpm. Contractors will be required to set up a prepaid account with the City of Golden. Accounts may be opened at the City of Golden Public Works office located at 1445 10th Street. Be prepared to provide company and truck information, including license plate numbers and truck capacity.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

PART 3 - EXECUTION

3.1 Limits of Exposure.

A. After construction begins, soil surface stabilization shall be applied with fourteen (14)days to all disturbed areas that may or may not be at final grade but will remainundisturbed for periods longer than thirty (30) calendar days or for an indeterminatelength of time. The maximum time limit of land exposure for the following erosioncontrol measures is shown by the following table:

Erosion Control Method Maximum Allowable Period of Exposure

(months)

Surface Roughening 1

Mulching 12

Temporary Revegetation 6 - 12

Permanent Revegetation 12 or more

Soil Stockpile Revegetation 2

Early Application of Road Base 1

Modified from Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual Volume 3 - Best Management Practices

3.2 Site Preparation.

A. Clearing and Grubbing: All damaged native shrubbery and trees adjacent to thedisturbed areas must be correctively pruned or removed. All large rocks, boulders,and construction debris must be removed from the site by the CONTRACTOR.

B. Grading: The disturbed area must be fine graded to allow for tractor-driven mowingmachinery. Transition from the disturbed areas to the original grade must have aneven, natural, and maintainable appearance.

3.3 Soil Preparation.

A. If needed prior to seeding, spray all areas that are to be seeded with "Roundup"herbicide or approved equal using a one percent (1%) solution as directed onpackaging. Do not contaminate surface waters during application(s) and leaveadequate residual time for the chemicals prior to seeding.

B. Thoroughly till all areas which are to be seeded and are 3:1 or flatter; areas thatpreviously supported vehicular traffic shall be tilled to a depth of twelve (12) inches,till all remaining areas to a depth of four (4) inches. Slopes which are steeper than3:1 shall be raked so that the top one-quarter (¼) inches of soil are loose and friablebefore seeding. Work the soil only when moisture conditions are suitable. Removerocks and other objects two (2) inches or greater in any dimension.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

C. Where required, apply soils conditioners immediately after fine grading.

D. Spread fertilizer and other soil amendments, when necessary, over all areas to beseeded by broadcast or drill seeding methods. Mix amendments into the top two (2)inches of soil by use of a harrow or rake until a uniform mixture is obtained with nopockets of soil or amendments remaining.

E. Correct irregularities in the ground surface resulting from soil preparation operationsand slope to drain. Confirm that all work is returned to final grade, per constructionplans, prior to seeding.

3.4 Seeding.

A. Seed all areas which have been disturbed as a result of construction operations.

B. Seed all areas which are flatter than 3:1 with a mechanical power-drawn drill whenpossible. When access is not possible, broadcast seeding is allowable. Allbroadcast seeding must be raked in prior to mulching.

C. Areas which are equal to or steeper than 3:1 shall:

1. Include the use of erosion control blankets.

2. Hydroseeding/mulching shall be used only in areas that are not accessible byother equipment/methods.

D. Seeding shall occur immediately after soil preparation and prior to erosion controlblanket installation.

E. Do not seed during windy weather or when the ground is frozen, muddy or untillable.

F. Seed at the rates specified in "PART 2 - MATERIALS."

G. Drill seeding: Set depth bands to a depth of three and one-half inches (3 ½”). Set tospace rows not more than seven inches (7”) apart. Sow seeds of different sizes fromat least two (2) separate hoppers adjusted to provide the proper coverage. The drillmust have the capacity to handle fluffy seeds adequately.

H. Broadcast seeding: Do not broadcast seed except in small areas which are notaccessible by machine methods. Distribute seed as evenly as possible. Rake in orotherwise cover seed with soil to a depth of one eighth inch (1/8”) to one quarter inch(1/4”).

I. Hydraulic seeding: Apply seed and fertilizer at the recommended rates. Performhydraulic spray applications in such a manner that the liquid carrier will uniformlydistribute the material over the entire area to be seeded at rates not less thanindicated herein. Equipment used for hydraulic seeding must meet the followingcriteria:

1. Equipment shall include a pump capable of being operated at one hundred(100) gallons per minute, at one hundred (100) psi.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

2. Equipment shall have an acceptable gauge and a nozzle adaptable tohydraulic seeding requirements.

3. Storage tanks shall have a means of agitation and a means of estimation ofthe volume used or remaining in the tank.

3.5 Mulch Application.

A. Mulch will be required for all seeded areas. Mulch should be applied immediatelyfollowing seeding operations.

B. Crimped Hay: Mulch areas with two (2) tons/acre grass hay or cereal grain straw.Spread uniformly by hand or mechanically. Immediately following application,stabilize mulch by means of crimping such that mulch is anchored at least two inches(2”) into the soil.. Follow with application of tackifier.

C. Hydromulch with tackifier: Mulch with hydromulch and tackifier. After seeding, applymulch in a separate hydraulic spray application. Combine mulch with water to createa slurry and apply according to manufacturer's specifications at a minimum rate oftwo thousand (2,000) pounds/acre. Perform hydraulic application of mulch in such amanner that the liquid carrier will uniformly distribute the material over the entireseeded area at rates not less than described herein. Do not perform hydraulic sprayapplications during windy weather.

3.6 Erosion Control Blanket.

A. After seeding, an approved erosion control blanket must be placed vertically on theslope. Bury upslope end in a narrow trench six inches (6”) deep and tamp trenchfirmly closed. Adjacent rolls should have a four inch (4”) overlap. Staple edges andcenters at two foot (2’) intervals. Slope shall be prepared to maximize contact withblanket. Correction of gaps and separation due to rocks or other debris will berequired.

B. All drainage swales shall be covered by erosion control blankets

3.7 Protection of Seeded Areas.

Protect seeded areas from unnecessary pedestrian or vehicular traffic until well established through the use of fences, barricades and signage. Provide any additional erosion control measures which are necessary for the successful establishment of vegetation.

3.8 Re-seeding and Repair.

Reseed and mulch areas where there is not a satisfactory stand of grass immediately following the CITY’s evaluation. The CONTRACTOR, at his discretion, may repair any areas at any time prior to a CITY evaluation.

3.9 Maintenance and Acceptance.

Care for seeded areas, including weed control and watering until Final Acceptance by the CITY. Seeded areas shall monitored monthly and be evaluated after one (1) full growing season. Acceptance depends on evidence of a satisfactory stand of grass and weed control.

CITY OF GOLDEN REVEGETATION REQUIREMENTS

A satisfactory stand of grass is defined as where a minimum of seventy percent (70%) of a planted area has an evenly distributed grass cover and a minimum of three (3) to four (4) desirable plants per square foot with limited occurrence of State listed Noxious Weed species.

3.10 Roads and Soil Stockpiles.

All non-paved portions of road cut, fill, and parking lot areas should be seeded and mulched as soon as possible after final grading has occurred, but in no case later than fourteen (14) days after the grading has been completed.

If stockpiles are located within close proximity to a drainageway (i.e., 100 feet) additional sediment control measures, such as a temporary diversion dike or silt fence, shall be provided.

END OF SECTION