ACKNOWLEDGEMENTS The City of Georgetown would like to thank the Lexington-Fayette Urban County Government (LFUCG) and the Sanitation District No. 1 of Northern Kentucky (SD1) for allowing the City to use the information presented in their respective Best Management Practice Manuals for the background, technical guidance and BMP Fact Sheets chapters. To review a list of the participants in LFUCG or SD1’s manuals or to view their documents visit:
http://www.lexingtonky.gov/index.aspx?page=780
http://www.sd1.org/ProjectsandPrograms/DevelopersandEngineersStormWaterInformation.aspx
In addition, the City of Georgetown would like to thank Strand Associates, Inc.® for working with us to compile this Stormwater Best Management Practices Manual with existing Georgetown requirements, updated policies, and local criteria to provide standards to assure quality and consistency in the design and construction of stormwater infrastructure within the City.
Finally, thank you to all those who took the time and effort to provide review comments and constructive suggestions on the draft versions of the Manual.
Acknowledgements
TABLE OF CONTENTS Chapter 1 - Introduction 1.1 Introduction and Purpose .............................................................................................................. 1-1 1.2 Goals and Objectives .................................................................................................................... 1-2 1.3 Local Conditions ........................................................................................................................... 1-3 1.3.A Climate and Hydrology 1.3.B Water Resources 1.3.C Geology 1.3.D Soils 1.4 Definitions ..................................................................................................................................... 1-8 1.4.A Public Drainage System 1.4.B Waters of Scott County 1.4.C Stormwater Facilities 1.4.D Floodplain 1.5 Acronyms .................................................................................................................................... 1-10
Chapter 2 - General Stormwater Standards and Permitting Requirements 2.1 General Stormwater Standards for New Development .................................................................. 2-1 2.1.A Construction in Waters of Scott County 2.1.B Regional Stormwater Management 2.1.C Ownership of Post-Construction Stormwater BMPs 2.1.D Lot Drainage in Residential Development 2.1.E Ownership and Maintenance of Drainage Easements 2.1.F Coordination with the National Flood Insurance Program 2.2 Permitting Requirements ............................................................................................................... 2-4 2.2.A Land Disturbance Permit 2.2.B KDOW KPDES NOI 2.2.C KDOW Floodplain Construction Permits 2.2.D 401 and 404 Permits- KDOW and USACE 2.2.E FEMA
Chapter 3 - Stormwater Management Plan Requirements 3.1 Stormwater Management Plan ...................................................................................................... 3-1 3.1.A Construction Plans 3.1.A.1 Existing Site Conditions Submittal Requirements 3.1.A.2 Proposed Site Improvements Submittal Requirements 3.1.A.3 Record Drawings 3.1.A.4 As-Built Drawings Table of Contents – 1
3.1.B Drainage Reports 3.1.C Additional Requirements 3.2 Stormwater Facility Maintenance Inspections ............................................................................... 3-7 3.2.A Stormwater Facility Construction Inspections 3.2.B Stormwater Facility Completion Certification 3.2.B Post-Construction Annual Inspection 3.3 Performance Security ................................................................................................................... 3-9
Chapter 4 - Stormwater Management Design Criteria 4.1 Approved Hydrologic Analysis Methods ........................................................................................ 4-1 4.1.A Design Storms 4.1.B Runoff Computation Methods 4.1.C Rational Method 4.1.D Time of Concentration 4.1.E Runoff Coefficients 4.1.F Soil Conservation Service Method 4.1.G Kentucky Transportation Cabinet Method 4.1.H Modified Rational Method 4.2 Water Quantity Design Criteria for New and Redevelopment ........................................................ 4-5 4.2.A Quantity Impacts 4.2.B Peak Flow Design Criteria 4.2.B.1 Detention/Retention Design Methods 4.2.B.2 Pre- and Post-Development Runoff Control 4.2.B.3 Storage Volume and Design Discharge 4.2.B.4 Design Standards 4.2.B.5 Maintenance Responsibilities 4.3 Water Quality Design Criteria for New and Redevelopment ........................................................ 4-10 4.3.A Impacts to Water Quality 4.3.B Water Quality Volume Criteria 4.3.C Targeted Pollutants 4.3.D Water Quality Credits 4.4 Groundwater Recharge Design Criteria....................................................................................... 4-15 4.5 Storm Sewer System Design Criteria .......................................................................................... 4-18 4.6 Culvert and Bridge Design Criteria .............................................................................................. 4-20 4.7 Open Channel Design Criteria .................................................................................................... 4-21 4.7.A Design Standards 4.7.B Manning’s Equation 4.8 Off-Site Mitigation........................................................................................................................ 4-23
Table of Contents – 2
Chapter 5 - Stormwater BMP Fact Sheets 5.1 Options for Stormwater Management ............................................................................................ 5-1 5.2 Approved BMP Fact Sheets ......................................................................................................... 5-2 Description Site Suitability Design Criteria Design Procedure Design Schematics Maintenance Considerations Typical Inspection Checklist 5.2.A Bioretention/Rain Gardens 5.2.B Bioinfiltration Swales 5.2.C Permeable Pavement 5.2.D Extended Detention Basins 5.2.E Wet Ponds 5.2.F Prefabricated Devices 5.2.G Sand Filters 5.2.H Constructed Wetlands 5.2.I Vegetated Filter Strips 5.2.J Riparian Buffers 5.2.K Terraforming 5.2.L Rooftop Disconnections 5.2.M Vegetated Channels
(Note: Fact Sheets are provided as a separate PDF file)
Appendices Appendix A - Long-Term O&M Agreement Appendix B - Plant Selection Appendix C - Bioretention Soil Mix Appendix D - Stormwater Post-Construction BMP Installation Inspection Report Appendix E - Post-Construction BMP Installation Certification Appendix F - Stormwater Management Plan Submittal Checklist
Table of Contents – 3
CHAPTER 1 Introduction 1.1
INTRODUCTION AND PURPOSE The City of Georgetown (City) and Scott County boast some of the most prestigious streams in Kentucky, including the North Elkhorn, South Elkhorn, and Eagle Creeks, which are used extensively for fishing and recreation and provide community assets that are important to the local economy. The City also obtains the majority of its water supply from the Royal Spring Aquifer, a natural resource unique in Kentucky, which is fed by groundwater recharge. Management of both stormwater quantity and quality in developed and developing areas transpired from the desire to protect human life, property, aquatic habitats. The United States Environmental Protection Agency’s (USEPA’s) National Pollutant Discharge Elimination System (NPDES) municipal and industrial permit requirements, total maximum daily loads (TMDLs), and watershed assessments are in place to facilitate protection of these habitats. The City developed this Stormwater Best Management Practices Manual (BMP Manual) as necessary guidance in response to growing community stormwater needs and evolving stormwater regulatory requirements. The BMP Manual provides an effective tool for the community to reduce both stormwater quality and quantity impacts, protect downstream areas and receiving waters, recharge the Royal Springs Aquifer, provide a means to maintain the integrity and durability of existing and proposed stormwater systems, and comply with increasingly more stringent post-construction requirements. The USEPA’s NPDES Phase II Rule applies to operators of regulated small municipal separate storm sewer systems (MS4) serving a population of less than 100,000 people in urbanized areas. The USEPA has delegated responsibility for the MS4 program to the Kentucky Energy and Environment Cabinet, of which the Kentucky Division of Water (KDOW) is a part. KDOW has designated the City as a Phase II community that must comply with the NPDES regulations that have been adopted by KDOW in accordance with 401 KAR 5:060 Section 12. The City, as the owner and operator of a small MS4, is required to reduce the discharge of pollutants from the MS4 waters of the Commonwealth and the United States to the “maximum extent practicable” to protect water quality. The Phase II Rule outlines six minimum control measures to help MS4s address this goal. The minimum control measures as defined by the USEPA are as follows:
Public Education and Outreach
Public Involvement and Participation
Illicit Discharge Detection and Elimination
Control of Construction Site Runoff
Post-Construction Stormwater Management
Pollution Prevention and Good Housekeeping
The purpose of the BMP Manual is to provide standards to assure quality and consistency in the design and construction of stormwater infrastructure that becomes owned or regulated by the City. By providing standard criteria to the engineers who study and design drainage infrastructure, the City is establishing uniformity in the design assumptions and general methods that are used for this purpose. The BMP Manual sets forth basic principles for effective stormwater management associated with land development and the need to address stormwater quantity, quality, and groundwater recharge. In serving this purpose, the BMP Manual outlines minimum standards for design, maintenance requirements for post-construction BMPs, and other guidance on the City’s stormwater program. 1–1
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GOALS AND OBJECTIVES Chapter 19, Article V Division III of the Georgetown Code of Ordinances, Section One: Control of Post-Construction Stormwater Runoff enacts the Georgetown/Scott County Subdivision and Development Regulations Section 1105. The Post-Construction Ordinance sets the prerequisite for this Stormwater BMP Manual. The BMP Manual seeks to expand upon the Post-Construction Ordinance’s goal to establish a set of water quality and quantity policies to provide effective and comprehensive guidance for the regulation of stormwater runoff from all public and private developments for the purpose of preserving local water resources from degradation. Disturbance to natural landscapes as a result of human activity is one of the most challenging issues facing stormwater management. Land development changes not only the physical but also the chemical and biological conditions of natural waterways and water resources. This BMP Manual provides guidance on the techniques and measures that can be implemented to meet a set of stormwater management minimum standards for new and redevelopment projects. The BMP Manual is designed to provide the site designer or engineer, as well as the local plan reviewer or inspector, with the information required to effectively address and control water quality, quantity, and groundwater recharge on a development site. This includes guidance on hydrologic techniques, criteria for the selection and design of structural stormwater controls, drainage system design, and construction and maintenance information. This BMP Manual prescribes the various methods that can be employed to effectively implement stormwater management practices to mitigate problems associated with stormwater runoff from new or redevelopment. This is accomplished by:
Protecting the municipal separate storm sewer system (MS4), community waters, and water of the Commonwealth.
Developing land in a way that minimizes its impact on a watershed, and reduces both the amount of runoff and pollutants generated, as well as proving groundwater recharge.
Maintaining after development, as nearly as possible, the pre-development runoff characteristics to reduce the adverse impacts of stream channel erosion, pollution, siltation and sedimentation, and local flooding caused by development.
Improving stormwater quality and treating post-construction stormwater runoff through stormwater management controls before it is discharged to a waterway and to ensure that these management controls are properly maintained and pose no threat to public safety.
Providing long-term responsibility for and maintenance of stormwater BMPs that are employed for fulfillment of these objectives.
The BMP Manual will be used by the City to review stormwater management plans and provide technical advice to meet the post-construction stormwater requirements. Parties involved with site development will use the BMP Manual for technical guidance and information including preparation of stormwater management plans, hydrologic techniques, selection and design of appropriate stormwater controls, drainage (hydraulic) design, and construction and maintenance of post-construction BMPs. Appendix A of the Manual includes the long-term operation and maintenance agreement to ensure all BMPs are maintained to function as designed. Where reference is made to a City of Georgetown’s Ordinance, the most current ordinance shall apply.
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1.3
LOCATION CONDITIONS 1.3. A Climate and Hydrology The climate in Georgetown, Kentucky is continental with a wide range of temperatures from winter to summer. Its location north of the Gulf of Mexico allows for plentiful amounts of precipitation that can vary extensively by season. This area of Kentucky within the Inner Bluegrass Region is in the transition area between the humid subtropical climate and the humid continental climate. This can cause significant variations between the four seasons from year to year. Temperature and precipitation patterns are summarized in Table 1.3-1. Table 1.3-1 Georgetown Temperature and Precipitation Patterns TEMPERATURE Normal (30-year record) Average annual (2012) Record highest, July 2012 (68-year record) Record lowest, January 1963 (67-year record) PRECIPITATION Normal (30-year record) Record total precipitation (2014) Sources Weather Underground; ThinkKentucky.com; NOAA.gov
55.5°F 57.6°F 105°F -21°F 45.17 inches 55.99 inches
1.3.B Water Resources The City is located within the Lower Subbasin of the Kentucky River Basin and contributes to five smaller subwatersheds: Cane Run, North Elkhorn Creek, Lanes Run, Dry Run, and McCracken Creek shown in Figure 1.3-1 and Figure 1.3-2. The Kentucky River Basin runs down the Eastern Kentucky Coal Fields, Knobs, and Bluegrass Regions to the Ohio River. Georgetown is located within the Lower Subbasin, which includes the most heavily populated region of the basin.
Figure 1.3-1 Kentucky River Basin
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Figure 1.3-2 Southern Scott County’s Watersheds Most of the local watersheds in the City are influenced by the impacts of civilization ranging from rural agricultural activities to suburban and commercial/industrial pressures to highly impervious urbanized areas. To keep track of the quality of Kentucky’s streams and lakes, KDOW updates the Kentucky 303(d) List (which identifies streams and lakes as impaired for identified pollutants or as not meeting one or more of the water quality standards) every two years. In general, impaired uses for these waterbodies include primary and secondary contact recreation and warm water aquatic habitat as either partially supporting or non-supporting. Typical pollutants of concern include bacteria, nutrients, and sediments. Currently, Cane Run is the only waterbody the City contributes runoff to with an approved TMDL. The TMDL for fecal coliform was approved in 2013. In addition, Dry Run and Royal Spring are listed on the 2012 303(d) List for impaired waters for nutrient, nitrogen, phosphorous, and sedimentation impairments. Many of the City’s waters are used extensively for fishing and recreation and protection of these resources is vital to the environment, public health, and the economy.
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As the main recharge area for the Royal Spring Aquifer, Cane Run originates in central Fayette County and flows north to discharge into the North Elkhorn Creek, draining approximately 44.6 square miles of Fayette and Scott Counties (Figure 1.3-3). Cane Run feeds the Royal Springs Aquifer, the primary drinking water source for the City, through a series of swallow holes that are hydraulically connected to the main karst conduit of Royal Spring. The Royal Spring Aquifer is susceptible to pollution within the Royal Spring karst basin where sink holes, streams, and caverns allow pollutants to easily enter into the groundwater system. The University of Kentucky’s College of Agriculture was awarded an EPA 319(h) grant to develop a watershed-based plan to outline strategies that will reduce, remediate, and prevent the effects of nonpoint source pollution in the watershed. The primary goal of the Cane Run and Royal Spring Watershed-Based Plan (WBP) is to reduce the effects of nonpoint sources of pollution in the watershed to allow the watershed to meet or exceed KDOW water quality standards.
Figure 1.3-3 Royal Spring Aquifer and Sinkholes
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1.3.C Geology The City lies within the Inner Bluegrass Region developed during the Ordovician Period, over 440 million years ago. This area is predominantly characterized by the exposed limestone or dolomite bedrock that lies at, or very near, the surface and is denoted as part of the Lexington limestone formation. The limestone through this part of Kentucky is nearly 320 feet thick as it extends through the Georgetown/Scott County area (Figure 1.3-4). According to the Kentucky Geological Survey, the characteristic gently rolling hills of the region are caused by weathering of limestone that has been pushed up along the crest of the Cincinnati Arch. In addition, the City’s location within the Inner Bluegrass Region is subject to the potential hazards of karst geology. Weathering of the limestone produces sink holes, sinking streams, springs, and caves as water passes through the horizontal weaknesses and vertical openings of the bedrock. Figure 1.3-4 Overview of Southern Scott County Geology
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1.3.D Soils Most of the City is comprised of silty loam-based soils ranging in slopes from 0 to 12 percent. The upper soil layer is underlain by clay, silty clay, and in some cases, weathered and unweathered bedrock. The National Resource Conservation Service (NRCS) has a classification system for soils that denotes the stormwater runoff potential of the soil; these are called the hydrologic soil groups (HSG). Group A has the lowest runoff potential as these soils consist of sandy soils and high infiltration rates. Group B has a moderate runoff potential with soils that have moderately fine to moderately coarse textures. Group C soils are typically sandy clay loam soils having moderately fine to fine textures and a low infiltration capacity. Group D soils, having a very high runoff potential, are comprised mostly of clay. The northern portion of Georgetown and areas of Scott County that drain to the City are made up of predominantly Group C soils whereas the southern portion of the City/County is made up of mostly Group B with seams of Group C soils. The following Figure 1.3-5 shows the HSG for the soils within Georgetown and southern Scott County.
Figure 1.3-5 Overview of Southern Scott County’s Hydrologic Soil Groups
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1.4
DEFINITIONS 1.4. A Public Drainage System The public drainage system for subdivided property shall begin at the point where the water from more than two lots combine or where water from one lot combines with water from a public road or other public facility. The public drainage system may be located on either public or private property. This definition of the public drainage system applies to areas covered by plans submitted after April 27, 2015. The public drainage system is divided into two parts: the constructed part and the natural part. The constructed part includes items such as pipes, overland flow channels, and swales that carry water from the beginning of the public drainage system to the portion of the drainage system that remains undisturbed, the natural portion. The natural portion of the public drainage system is referred to as the Waters of Scott County as defined in Section 1.4.B. An adequate drainage easement shall be required for all of the public drainage system not already in a street right-of-way. The easement shall be of sufficient width to allow cleaning, widening, deepening, replacing, and generally maintaining the public drainage system. The minimum width of the drainage easement shall be 15 feet. Easements shall be in favor of the general public, granting all property owners within the watershed the right to pass stormwater over, beneath and through said easement and providing the City and its designee the right to enter upon the easement and to make such repairs and alterations to the drainage system as may be necessary to ensure the adequate operation of the drainage system. The aforesaid rights granted to the City shall in no way affect the legal responsibility for maintenance and repair of the drainage system as established by the laws of the City and/or by agreement. The City shall assume responsibility for any portion of the public drainage system specifically dedicated to and accepted by the City for maintenance, including all portions of the drainage system within dedicated street right of ways.
1.4. B Waters of Scott County The Waters of Scott County are the natural portion of the public drainage system that shall remain undisturbed. These include: Intermittent and perennial streams represented on the United States Geological Survey (USGS) 7.5 minute topographic maps as either solid or dashed blue line streams; channels that are not shown as a solid or dashed blue line shall be considered a stream if they have a drainage area of at least 50 acres.
Other channels that may be added because they display a nature similar to those designated as a blue line on the USGS maps or as determined by United States Army Corps of Engineers (USACE) and/or KDOW.
Reservoirs, lakes, ponds, and other impoundments on the streams, or in many cases that are the beginning of the stream.
Wetlands and areas of more than 1/2 acre according to the current wetland delineation criteria used by the USACE and buffer area of 25 feet around the wetland.
Floodplain.
Groundwater flowing in the soil and rock formations beneath Scott County.
A vegetative buffer strip extending 25 feet horizontally from the top of bank elevation for perennial streams and 25 feet from the centerline of intermittent streams.
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1.4. C Stormwater Facilities Stormwater facilities, also known as best management practices (BMPs), include infrastructure that is designed and constructed to meet the water quantity and water quality requirements of this manual. A list of pre-approved stormwater quality controls is included in Chapter 5 of the BMP Manual.
1.4. D Floodplain A floodplain is defined as the area along a stream or watercourse that could be periodically submerged as the result of a rainfall with a 100-year return period. The floodplain shall be as shown on the Federal Emergency Management Administration (FEMA) Firm Flood Insurance Rate maps (FIRM) for those stream segments included in the maps, and/or as designated in Section III.A.2 of the Environmental Quality Management Plan of the Scott County Comprehensive Plan for Creek Conservation Corridors not on the FEMA maps. Georgetown and Scott County Creek Conservation Corridors, zoned C-1, are protected under Article XII Sec. 1200, A of the Subdivision Regulations.
Figure 1.4-1 Georgetown FEMA Floodplains 1–9
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ACRONYMS BFE BMP CFR CLOMR CWA EPSC FEMA FIRM GSCPC HOA HQWs HSG KDOW KPDES KYR10 KYTC LDP LOMR MEP MRM MS4 NEH NFIP NOAA NOI NOT NPDES NPS NRCS O&M PUD RCP RPR SCS SFHA SWPPP Tc TMDL USACE USDA USEPA USGS WBP WQv
Base Flood Elevation best management practice Code of Federal Regulations Conditional Letter of Map Revision Clean Water Act Erosion Prevention and Sediment Control Federal Emergency Management Agency Flood Insurance Rate Map Georgetown Scott County Planning Commission Home Owners Association high quality waters hydrologic soils group Kentucky Division of Water Kentucky Pollutant Discharge Elimination System KPDES Permit for Construction Activities KYR100000 Kentucky Transportation Cabinet Land Disturbance Permit Letter of Map Revision Maximum Extent Practicable Modified Rational Method Municipal Separate Storm Sewer System National Engineering Handbook National Flood Insurance Program National Oceanic and Atmosphere Administration Notice of Intent Notice of Termination National Pollutant Discharge Elimination System Nonpoint Source Natural Resources Conservation Service Operation and Maintenance Planned Urban Development reinforce concrete pipe resident project representative Soil Conservation Service Special Flood Hazard Area Stormwater Pollution Prevention Plan Time of Concentration Total Maximum Daily Load United States Army Corps of Engineers United States Department of Agriculture United States Environmental Protection Agency United States Geological Survey Watershed-Based Plan Water Quality Volume
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CHAPTER 2
General Stormwater Standards and Permitting Requirements 2.1
GENERAL STORMWATER STANDARDS FOR NEW DEVELOPMENT 2.1. A Construction in Waters of Scott County In general, construction activities shall not be allowed in the waters or floodplains of Scott County. Excavation in the floodplain to lower flood levels shall not be permitted. Only the following activities may be undertaken in the waters or floodplains:
Temporary sediment ponds that will be converted to a permanent stormwater management pond.
Roadways and utilities that cross at angles within 10 degrees of being perpendicular to the stream or floodplain.
Storm sewer pipe outlets where the outlet terminates at the edge of the floodplain.
Regional flood control or water quality control ponds constructed by the City.
Other flood control practices that do not disturb below the normal top of bank of the stream.
Water quality practices that do not disturb below the normal top of bank of the stream.
Pedestrian crossings and trails.
Where minimal grading results in no net loss of floodplain storage volumes, does not disturb or damage creek bank vegetation and natural floodplain area soils, and does not alter the natural flood channel or stream hydrology.
If situations arise where there are no feasible alternatives to construction in a waterbody or floodplain, the area disturbed because of grading and/or other construction activities must be stabilized and comply with the City’s Flood Damage Prevention Ordinance No. 13-028, including application for a development permit through the Planning Commission Engineer (Floodplain Administrator) . In addition, all required permits shall be acquired through the approving regulatory agencies, see Section 2.2. Engineers are encouraged to protect channel and waterways by not designing developments that require fill in headwater stream channels to within 50 feet of the bankfull conditions (1.5- to 2-year return periods) of minor waterways, and floodplains. Developments that utilize this option may qualify for density credits or other considerations similar to a Planned Urban Development (PUD).
2.1. B Regional Stormwater Management The City encourages regional stormwater management facilities when practicable. The City will work toward developing a Stormwater Master Plan to identify areas within the City that will benefit from regional facilities and establish programs to assist with the creation of such facilities. This can be more cost-effective than requiring each small development project to construct its own stormwater facilities. In addition, the long-term maintenance requirements may be less because there will be fewer of these small facilities to maintain. These kinds of efforts may require two or more developers to jointly fund the construction of a common water quality and/or water quantity practice and would necessitate a cooperative agreement between the developers. In situations where a regional facility is desired, the City will assist in review of cooperative agreements between property owners for maintenance and allocation of responsibilities.
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2.1. C Ownership of Post-Construction Stormwater BMPs The property owner or Responsible Entity shall own, operate, and maintain stormwater BMPs in residential, commercial, and industrial developments within the Georgetown City limits to ensure their proper operation. Each property owner shall bear proportionate responsibility for the operation and maintenance (O&M) of the BMPs specified in the stormwater management plan. Shared responsibility shall be governed by a separate legal entity (the “Responsible Entity”), such as a HOA, sufficient to operate, maintain, and provide for the revenue necessary to operate and maintain the BMPs. The responsibility for operation, maintenance, and inspection of BMPs shall be borne proportionally based on the number of lots owned by the property owner over the total number of lots whose stormwater runoff is controlled or treated by the BMPs as specified in the stormwater management plan. Property owners may enter into an agreement amongst themselves regarding equitable allocation of cost for O&M, but any such agreement shall not alter the proportionate responsibility as set forth in Georgetown’s Post-Construction Ordinance.
2.1. D Lot Drainage in Residential Development Constructed channels shall be provided for drainage areas greater than 1 acre in residential developments. The channel shall be designed to carry the 100-Year Storm Event. The drainage easement along the channel shall be 15 feet wide, or the width of the 100-year flow plus 5 feet on each side, whichever is wider. The engineer shall design these channels as part of the stormwater management plan. The design criteria are contained in Section 4.7.A. Channels in back yards and side yards that receive runoff from a storm sewer or culvert shall have a paved (generally concrete) trickle channel. The design criteria for the trickle channel are contained in Section 4.7.A.
2.1. E Ownership and Maintenance of Drainage Easements Drainage easements contain stormwater channels, pipes, stormwater storage areas/facilities, and post-construction stormwater BMPs, as well as access rights for maintenance of such facilities. No channel alteration or construction that would obstruct the flow of stormwater is allowed within the drainage easement. There shall be no storage or disposal of grass clippings, trash, debris, or other potential obstructions that may wash into stormwater channels or other stormwater management facilities. The property owner or responsible entity is responsible for maintaining all public drainage system easements on private property. Maintenance activities include routine mowing, as well as cleaning and repair of major structural items such as pipes, paved channels, and headwalls. Property owners shall not construct anything in the public drainage system, including the Waters of Scott County adjoining their property that will impede the flow of water.
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2.1. F Coordination with the National Flood Insurance Program Construction within the FEMA Special Flood Hazard Area shall comply with the City’s Flood Damage Prevention Ordinance No. 13-028, the requirements of the Commonwealth of Kentucky, and the requirements of the National Flood Insurance Program (NFIP) (44 CFR 59 - 44 CFR 75). For developments that contain the FEMA Special Flood Hazard Area, a Floodplain Development Permit shall be obtained before any construction or other development begins. For developments containing the FEMA Special Flood Hazard Area (SFHA), the following minimum requirements shall apply:
The 1 Percent Annual Chance Special Flood Hazard Area and the 1 Percent Annual Chance Floodplain shall be shown on the stormwater management plan and plats.
No construction that would affect the hydrologic or hydraulic characteristics of a flooding source and thus result in the modification of the existing regulatory floodway, the effective base flood elevations, or the SFHA are permitted unless a Conditional Letter of Map Revision (CLOMR) or a CLOMR-F, is obtained before construction (44 CFR 72.1).
Upon completion of the construction described in the CLOMR or CLOMR-F, the developer must obtain the final Letter of Map Revision (LOMR) or LOMR-F from FEMA (44 CFR 72.1).
Any other physical change which may affect flooding conditions must be submitted to FEMA for a LOMR within six months of the change being made (44 CFR 65.3).
All CLOMR, CLOMR-F, LOMR, LOMR-F, and any other applications to FEMA for map changes must be reviewed and signed by the Planning Commission Engineer before being submitted to FEMA.
All other provisions of the NFIP, whether specifically listed above or not, are applicable to all proposed development within the City.
In the event of conflict between local, state, and federal regulations, the more stringent regulation shall govern.
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2.2
PERMITTING REQUIREMENTS 2.2. A Land Disturbance Permit Any land disturbance activity that requires the disturbance of soil 5,000 square feet or greater in area shall obtain a permit for land disturbance as prescribed in the City and Georgetown-Scott County Planning Commission’s (GSCPC) Erosion Prevention and Sediment Control Ordinance No. 2010-014. The Land Disturbance Permit (LDP) shall be submitted by the contractor with the appropriate permitting fee, reviewed, and approved by the Planning Commission Engineer or Building Inspection based on the type of project.
Tier I LDPs and stormwater pollution prevention plans (SWPPP) shall be prepared and submitted to Building Inspection for land disturbance activities associated with single family and duplex lot building projects. Tier I shall also apply to additions and/or alterations of existing structures greater than 5,000 square feet and less than one acre of disturbed area, as covered by the Building Permit. Note: Lots that are part of a common plan of development that currently has permit coverage under a KPDES Notice of Intent (NOI) may qualify to submit a TIER I SWPPP if the SWPPP plan for the common plan of development has included single lot perimeter controls as part of the plan.
Tier II LDPs and SWPPPs shall be prepared and submitted to the Planning Commission Engineer for land disturbance activity meeting the requirements of KYR10 (disturbance cummulatively equal to one acre or more or is part of a larger common plan of development or sale if the larger common plan of development will ultimately disturb one acre or more) and those not covered under the Tier I SWPPP. LDP applications shall be submitted after the Planning Commission Engineer approves the stormwater management plan, including the Erosion and Sediment Control Plan for the site. See Chapter 3 for stormwater management plan submittal requirements.
City Projects shall be submitted to the City Engineer for plan review. No land disturbance activities shall commence before the City Engineer’s approval of the SWPPP and verification of coverage under KYR10 if applicable.
For State-Funded Projects within the City, the City Engineer will engage the Kentucky Finance and Administration Cabinet to review applicability for a Public Facilities Plan Review on a case-by-case basis to ensure planned development is in conformance with the City’s stormwater requirements for construction and post-construction activities.
Before construction, a LDP and Grading Permit must also be obtained for Tier II projects. A grading plan prepared by a licensed design professional must be submitted to the Planning Commission Engineer and include existing grade and proposed land disturbances, fills, soil storage, and locations of existing and proposed storm sewer systems and management facilities. A pre-construction meeting with Building Inspection is required for all new development and redevelopment projects requiring a LDP. LDPs will be closed and terminated when the Planning Commission Engineer or Building Inspection determine the following:
Final stabilization has been established. A copy of the Notice of Termination (NOT) submittal to KDOW (if applicable) was received. A Certificate of Stabilization or Certificate of Occupancy for a project also covered by a Building Permit is issued.
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2.2. B KDOW KPDES NOI Proof of coverage under the Kentucky Pollutant Discharge Elimination System (KPDES) General Permit for stormwater discharges related to construction activities (an approved NOI) shall be provided before a Tier II LDP will be issued. The KPDES General Permit requires, among other things: 1. The submission of a NOI to KDOW before construction begins. 2. The preparation of a comprehensive SWPPP, which includes an erosion and sediment control plan, to be kept on-site at all times. 3. A description of procedures to maintain erosion and sediment control measures during the period of construction. 4. A description of the intended sequence of major stormwater controls and an implementation schedule in relation to the construction process. 5. The identification of each contractor or subcontractor who will install each erosion and sediment control measure. 6. The signing by each contractor or subcontractor of a statement certifying the awareness of the requirements of the KPDES Stormwater Permit for the site. 7. The inspection by qualified personnel, provided by the developer, of the site at least once every 7 calendar days, or at least once every 14 calendar days and within 24 hours of the end of a storm of 0.5 inch or greater. 8. The submission of a NOT to the KDOW with a statement certifying that all stormwater discharges associated with the construction activity have been eliminated. Construction shall not begin until the NOI and items 2 through 6 above are completed and the NOI is provided to KDOW with a copy to the Planning Commission Engineer. During the construction process, evidence of the inspections listed in item 7 above shall be retained with the SWPPP on-site. Inspection reports and update-to-date SWPPP will be reviewed as part of the City’s periodic inspection process.
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2.2. C KDOW Floodplain Construction Permits Pursuant to Kentucky law, dams or other improvements obstructing the movement of water in the floodplain are often regulated by KDOW. A Floodplain Construction Permit is required from KDOW of the Environmental and Public Protection Cabinet prior to the construction, reconstruction, relocation, or improvement of any dam, embankment, levee, dike, bridge, fill, or other obstructions across or along any stream or in the floodway of any stream. Permits are required for any such activity in designated 100-year floodplains or areas known to be flood-prone. Exemptions may exist for activities in watersheds of less than one square mile of drainage. A permit from the KDOW is also required to deposit or cause to be deposited any matter that will in any way restrict or disturb the flow of water in the channel or in the floodway of any stream. In addition, a KDOW permit is required prior to the construction of structures qualifying as dams. A structure is defined by KDOW as a dam if the vertical distance from the downstream toe to the crest of the embankment is 25 feet or greater, or if the structure has the potential for impounding, either temporarily or permanently, 50 acre feet or more, measured to the crest of the embankment. Impoundment structures of lesser size may also warrant permitting by KDOW if downstream hazard conditions warrant such consideration. In instances where KDOW permits are required, construction shall not begin until evidence of the Floodplain Construction Permit, or a determination that no permit is required, is provided to the Planning Commission Engineer and City Engineer. In the case of dams, where water will be impounded on a temporary basis, construction shall not begin on facilities dependent upon the dam until an approval by the KDOW to impound water has been obtained. The permitting requirements apply to dams constructed for sediment and erosion control, stormwater detention, or just aesthetic amenities. The requirements also apply to other flow obstructions like pump stations. Fills not impounding water are a class of obstruction that are covered under this requirement. A KDOW Floodplain Construction Permit is not required for a fill if the drainage area above the fill is less than or equal to 1 square mile and the fill does not impede the flow of naturally draining runoff from the upstream area.
2.2. D 401 and 404 Permits- KDOW and USACE The KDOW Floodplain Construction Permit addressed above only relates to the potential flooding from the construction of an obstruction to the flow of water in the stream or floodplain. KDOW has another permitting program (Section 401 permit) related to construction that impacts the stream channel and areas below the ordinary high water level. In general, construction below the ordinary high water level is not envisioned in the waters of Scott County. However, if situations arise where construction is necessary below the ordinary high water level or in wetlands, KDOW administers regulations and requirements for projects that impact these waters. In addition, the USACE has requirements for projects that impact waters of the United States, including wetlands. Where the KDOW Section 401 or USACE Section 404 permits, including coverage under the USACE Nationwide Permits, are required, construction shall not begin until evidence of the 401 and/or 404 permits or a determination that no permit is required is provided to the Planning Commission Engineer. Permit applications and related plans for projects requiring a jurisdictional review shall be submitted to the USACE and KDOW. Copies shall also be submitted to the Planning Commission Engineer.
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2.2. E FEMA FEMA manages the NFIP based on maps showing floodplains and flood hazard areas. As part of the agreement for making flood insurance available in Scott County, the NFIP required the City to adopt floodplain management ordinances containing certain minimum requirements intended to reduce future flood losses. The City is also responsible for submitting data to FEMA reflecting revised flood hazard information so that the NFIP maps can be revised as appropriate. Up-to-date maps allow risk premium rates and floodplain management requirements to be based on current data. In instances where construction in the floodplain changes the floodplain elevations or the shape of the floodplain as shown on the NFIP maps, FEMA has a procedure for revising the maps. In general, construction in floodplains is not envisioned in Scott County except for road and utility crossings and the construction of sanitary sewer and stormwater management facilities. In some instances, construction of these facilities may change the floodplain elevations, necessitating the filing of documents with FEMA to revise the floodplain maps. In other instances, the FEMA maps may incorrectly show the floodplains. Where a floodplain is shown incorrectly, the filing of documents with FEMA is required to correctly define the floodplains. Construction activities within the FEMA floodplain shall comply with the requirements of the City’s Flood Damage Prevention Ordinance No. 13-028. For projects that change the FEMA floodplain, the engineer shall submit the appropriate technical data to FEMA. The requirements for submitting the data can be obtained from the Planning Commission Engineer. Areas designated as Zone A on Flood Insurance Rate Maps do not have base flood elevations (BFE) established. It is acceptable to estimate the BFE by superimposing the Zone A limits on a 2-foot contour map and interpolating between the contours provided that the contours were created on a similar vertical datum as the FEMA maps.
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CHAPTER 3
Stormwater Management Plan Requirements 3.1
STORMWATER MANAGEMENT PLAN A Stormwater Management Plan must be submitted by the applicant for approval (paper and PDF submittal) in accordance with Chapter 19, Article V Division III of the Georgetown Code of Ordinances, Section One: Control of Post-Construction Stormwater Runoff. The applicant shall be the property owner or his or her designee, such as the developer (Responsible Entity). All stormwater management plans are to be reviewed and approved by the Planning Commission Engineer. The applicant shall submit the Stormwater Management Plan with the Submittal Checklist found it in Appendix F. The stormwater management plan shall include all the following required information:
Contact Information The applicant name (Responsible Entity), address, and telephone number and the tax reference number and parcel number of the property or properties affected.
Topographic Base Map See Section 3.1.A Construction Plans for a description of requirements.
Stormwater Management Facilities The stormwater management plan shall clearly delineate all detention basins, pipes, inlets, culverts, channels, etc. required to meet the stormwater management design criteria in Chapter 4 of this Manual. This shall also include proposed post-construction stormwater BMPs.
Post-Construction Stormwater BMP(s) Approved water quality related practices as detailed in Chapter 5 of this Manual shall be used in developing stormwater management plans, where required, to satisfy the water quality design criteria. Refer to Section 4.3 for water quality design criteria applicable to new development and redevelopment projects.
Design Documents The stormwater management plan shall include construction plans and specifications showing all details necessary to construct the proposed improvements, including a drainage report with all engineering calculations to comply with design requirements for each element of the stormwater system of improvements. See Section 3.1.A Construction Plans and Section 3.1.B Drainage Reports.
Calculations and Soil Information See Section 3.1.B Drainage Reports for a description of requirements.
Erosion and Sediment Control Plans for Construction The applicant must prepare a SWPPP, Erosion Prevention and Sediment Control (EPSC) Plan, and Grading Plan as applicable to the project, in accordance with the City’s Erosion and Sediment Control Ordinance No. 2010-014. These requirements apply for all construction activities related to on-site land disturbance activities. The plans shall include a vegetation rejuvenation plan listing who will be responsible for the establishment and maintenance of vegetation at the site and practices that will be employed to ensure adequate vegetative cover is maintained and preserved.
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Stormwater Management/BMP Facilities Operations and Maintenance Agreement The applicant must execute an operations and maintenance agreement binding on all subsequent owners of land served by Stormwater Management/BMP facilities in accordance with the requirements of this BMP Manual. Applicable inspection schedules and maintenance checklists, including any manufacturer-provided schedules shall be incorporated with the Agreement. See Appendix A for the operations and maintenance agreement template.
Landscaping Plan If the construction drawings include the installation of a post-construction stormwater BMP(s) requiring vegetation and plant material, the landscaping plan shall be included as an attachment to the Post-Construction Stormwater BMP Operations and Maintenance Agreement. The landscaping plan shall be used as a reference for ongoing maintenance of the post-construction BMP vegetation, including a listing of the practices that will be employed to ensure that the vegetation is continually preserved.
Drainage Easements The applicant must ensure suitable access to all stormwater facilities (i.e., right-of-entry granted by the property owner to the City) for the purpose of ongoing inspection, maintenance, and repair. Right-of-entry shall be in legal form with easements sufficient for this purpose by deed or record plat.
Record Drawings Record drawings for all storm drainage-related infrastructure shall be submitted upon completion of construction to document the actual construction and reflect all changes made in the specifications and construction drawings during the construction process. See Section 3.1.A.3 Record Drawings.
As-Built Drawings Upon final completion of a required post-construction stormwater BMP, the applicant shall submit stamped and signed “as-built” drawings accompanied with a completion certification by a licensed design professional (Design Professional). See Section 3.2.B Stormwater Facility Completion Certification.
Stormwater BMP Construction Cost Estimate The applicant shall provide an itemized estimate of probable cost prepared by the Design Professional for the proposed post-construction stormwater BMP(s).
Other Environmental Permits The applicant shall ensure that all other applicable regulatory permits have been acquired for the project prior to approval of the final Stormwater Management Plan. Copies of all applicable permits obtained shall be submitted with the stormwater management plan.
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3.1. A Construction Plans Construction plans for stormwater management facilities shall include details related to all aspects of the proposed construction. Developments shall be designed with sequencing plans to ensure that proper controls are in place that will minimize or prevent adverse water quality impacts throughout all phases of construction. The Design Professional shall develop implementation strategies, which could include a combination of structural and/or nonstructural stormwater BMPs as appropriate for both peak flow control and post-construction water quality requirements. 3.1. A.1 Existing Site Conditions Submittal Requirements A topographic base map of the project site and adjacent areas shall be provided, of the same scale as the preliminary plat or plan, unless the Planning Commission Engineer requires a greater scale because of unusual site characteristics. This map shall detail the following:
Existing streams, floodplains, and calculated high water elevations. Any C-1 zones. Shorelines of lakes, ponds, and wetlands. Sinkholes and their drainage areas. Existing detention basins including their inflow and outflow structures, if any. All existing sanitary sewers and their flowline elevations. Aerial drainage patterns leading onto and off of the proposed project site. Other pertinent features.
3.1. A.2 Proposed Site Improvements Submittal Requirements The proposed stormwater management system drawn on a topographic map similar to that required by Section 3.1.A.1, shall identify the location of all drainage structures including the following information:
Flowline elevation, slope, type, and size of storm sewers and waterways discharging onto the site and receiving storm sewers and waterways at the points into which stormwater from the site will drain.
Where existing channels or other open drainage facilities will be changed either by construction or by increasing the flow and/or volume therein, provide a profile and one or more cross sections of the existing and proposed channels or other open drainage facilities, showing existing conditions and the proposed changes thereto, together with the high water elevations expected from stormwater runoff and the relation of structures, streets, and other utilities to such channels.
Identification of the means by which open channels shall be protected from erosion (appropriate vegetative cover, lining or other treatment) in accordance with Section 4.7.A.
Identification of an overflow channel through the development, which shall where feasible preserve and utilize the existing natural drainage system on the site. Demonstrate that the overflow channel capacity will transport the peak runoff from a 100-year, 24-hour storm, and that in such a storm, the water surface elevation(s) shall be at least 2 feet below the finish floor elevation of any existing or proposed buildings.
Demonstration that proposed alterations to any natural drainage ways or channels will not decrease their hydraulic capacity to the extent that it causes adverse impacts upstream or
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downstream from the proposed development. Note: See also Article XII, Section 1200 of the Subdivision Regulations concerning protection of environmentally sensitive areas.
Demonstration that no sinkhole is to be altered for use in the stormwater management system, nor will any ponding condition at the inlet end of any off-site receiving structure, including sinkholes, be increased, and that the energy gradient into subsurface conduits is not increased beyond the slope of the conduit.
Demonstration that the development within the sinkhole drainage area does not increase the total volume of runoff into a sinkhole and all post-developed discharges are routed through a post-construction water quality BMP prior to draining into the sinkhole limits. Where circumstances warrant, the Planning Commission Engineer may request additional studies and/or subsurface investigations.
All stormwater facilities and inflow and outflow structures must be evaluated to include, if applicable, the following: 1. A plot or tabulation of storage volumes with corresponding water surface elevations shall be provided showing there is adequate capacity to contain the storage volume of tributary stormwater runoff with at least 1 foot of freeboard above the calculated high water elevation for the 100-year, 24-hour storm. Note: The minimum floor elevation of any structures or buildings adjacent to these areas shall be set at least 2 feet above the 100-year, 24-hour peak stage. 2. Anti-seep collar details shall be provided for stormwater impoundment facilities that have dewatering times greater than 48 hours, permanent pools, or as required by other regulatory approving agencies. 3. Dewatering features, such as valve structures and/or underlying drain systems shall be included as applicable for facilities other than standard detention system designs (e.g., permanent pools, constructed wetlands, infiltration basins, and bioretention areas). 4. Water balance calculations shall be performed for all stormwater facilities with permanent pools, including wet ponds as defined in Chapter 5.2.E. The calculations should demonstrate that adequate water supply will be present to maintain a pool of water during a drought year when precipitation is 50 percent of average for the site. 5. Outlet pipes for all stormwater detention basins and impoundments shall be reinforced concrete with gasketed joints. These systems shall also be pressure rated where required by other approving agencies. 6. Construction plans shall detail any special construction requirements including compaction standards and tolerances for all proposed water impoundments, dams, and channel/stream crossings. 7. A permanent means of access for inspection, maintenance, and repair shall be provided to all proposed stormwater facilities and clearly shown on the construction plans.
Where permitted, stormwater impoundment facilities shall serve as temporary sediment basins until the contributing drainage area exceeds 90 percent build-out and 80 percent site stabilization. At that time, they shall be converted over to the approved post-developed stormwater control facility.
Acknowledgement of certification criteria required for all proposed bridge structures to be certified by the licensed professional engineer upon completion of the project, as outlined in Chapter 4.6. 3–4
3.1. A.3 Record Drawings A record of all stormwater infrastructure shall be submitted upon completion of construction. The record drawings shall include the following: Plan sheet and profile of storm sewers and inlets, showing the invert elevation(s) at each inlet structure.
Grate elevation of each curb and surface inlet.
Plan sheet and profile of constructed channels.
Plan sheet and profile of principal and emergency spillways, showing the as-built inlet and outlet invert elevations.
Plan sheet and sections of risers, showing the as-built size and elevation of orifices and weirs.
Plan sheet, profiles, and details of stormwater controls.
1-foot contour map of constructed detention basin(s) including a tabulation of as-built storage volume.
Volume verification of underground detention and other alternative quantity based stormwater control systems.
Manhole and inlet structure types.
One hard copy and CD of a CCTV inspection report for the constructed storm sewer system.
3.1. A.4 As-Built Drawings The Licensed Design Professional shall provide stamped and signed as-built drawings of any installed post-construction stormwater quality BMPs. The as-built drawings shall be submitted in PDF format to the Planning Commission Engineer and accompanied with a compatible CAD file of the line work used in preparing these drawings. Post-construction stormwater BMP components vary widely, but requirements for each BMP are summarized in Chapter 5 of this Manual. At a minimum as-built drawings shall include the following: Plan sheet and profile of as-built surveyed locations and elevations of the water quality BMP(s), showing any invert and grate or manhole elevation(s).
Plan sheet and profile of surveyed locations and invert elevations of swale(s).
Plan sheet and profile of principal and emergency spillways, showing the as-built inlet and outlet invert elevations.
Plan sheet and sections of water quality risers, showing the as-built size and elevation of orifices and weirs.
1-foot contour map of constructed water quality basin(s) including a tabulation of as-built storage volume.
Manhole and inlet structure types associate with the water quality BMP(s).
Approved material specifications from construction, including approved soil mix designs, if applicable.
Verification of material cross sections installed for applicable water quality BMPs, (e.g., Bioretention Basins, Rain Gardens, and Permeable Pavements).
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3.1. B Drainage Reports The Design Professional is required to provide calculations and studies that support the use of the various Stormwater Management Facilities and Post Construction Stormwater BMPs specified in the plan. These studies are to be submitted in conjunction with the Construction Plans for the proposed development. The following is a list of minimum criteria to be included in all drainage reports:
Summary tables outlining all hydrologic parameter values needed to support the stormwater management plans. Soil survey maps showing the existing soil conditions for the study area. Ponding elevations for each of the proposed stormwater structures, stormwater facilities, and closed contour areas. Flow depths for all open channel conditions that are a part of the proposed plan. Identification of all swales, diversion ditches, roadway ditches, 100-year drainage ways, and floodplains. Evaluation of stormwater systems that receive runoff from the proposed development; receiving systems are defined as any type of structure, open channel, or closed conduit that conveys runoff. Pre- and post-developed watershed maps showing all parameters used by the Design Professional to produce the stormwater plan. Maps that show all subcatchments draining to each proposed structure. Labeled analysis point where the study terminates. All points of analysis are to be set to evaluate the potential of compounding peak flow conditions downstream of the proposed development. Analysis points are to be approved by the Planning Commission Engineer. Calculations to demonstrate that BMPs included in the construction plans meet the stormwater peak flow and water quality standards for new development or redevelopment projects, as applicable.
3.1. C Additional Requirements All new development and redevelopment projects must also incorporate the following criteria into their designs:
Finish floor elevations for proposed single- and multi-family residential units, commercial buildings, and other habitable structures shall be at least 2 feet above the 100-year water surface elevations for all waterways, overflow conditions, overland flow areas, and ponding areas. Designs are not to include any fill to be placed in 100-year drainage ways and floodplains, unless proposed construction complies with Article XII, Section 1200 of the Subdivision and Development Regulations. Any and all required permits from federal, state, and local agencies must be obtained prior to approval for any placement of fill in such areas. Other than what is described above, any and all permits required by federal, state, and local agencies for proposed development must be obtained prior to construction.
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3.2
STORMWATER FACILITY MAINTENANCE INSPECTIONS 3.2. A Stormwater Facility Construction Inspections The Property Owner or Responsible Entity (Responsible Entity) shall engage a licensed Design Professional to provide inspection services during the installation of post-construction stormwater BMPs as outlined in the stormwater management plan. The Design Professional shall be responsible for reviewing and observing conformity of the work being performed by the contractor with the requirements outlined in the approved construction plans and specifications for each post construction BMP. The Planning Commission Engineer and City Engineer may also at their discretion make independent inspections as deemed necessary. These required inspections shall be performed during all phases of post-construction stormwater BMP construction to document the various components comprising the BMP once completed. See Appendix D for a copy of the installation inspection report form. Documentation for field inspection services shall include a report that references the various components that have been installed during each inspection period, in accordance with the Installation Certification Checklist. A copy of each inspection report shall be submitted to the Planning Commission Engineer by the end of the next business day following the date of the site visit. The Design Professional shall be responsible for documenting any material deviations from the approved plans and specifications that are observed during the installation of the BMP. If material deviations are observed, the Design Professional shall also immediately notify the Responsible Entity and Planning Commission Engineer of any such occurrences. This shall include a written discussion of the necessary corrective actions to be taken, if required to address the deviations. The Planning Commission Engineer and City Engineer may at their discretion require additional corrective actions as deemed necessary. In addition, the Responsible Entity shall notify the Planning Commission Engineer at least twenty-four (24) hours in advance of placing any permanent cover over stormwater infrastructure that may include storm pipe and other drainage related improvements. This notice requirement is intended to permit opportunity for inspection by the Planning Commission Engineer or City Engineer if deemed necessary.
3.2. B Stormwater Facility Completion Certification Upon completion of construction for the BMP(s), the Design Professional shall submit the final installation inspection report and the Post-Construction BMP Installation Certification and Checklist found in Appendix E. Submittal and acceptance of these documents is a prerequisite to the issuance of the Certificate of Occupancy and/or approval of the final record plat for new development or redevelopment projects. Where applicable, the Operations and Maintenance Agreement for post-construction stormwater BMPs shall be executed before final development plan or final subdivision plat approval and shall be recorded before the Certificate of Occupancy or final subdivision plat is approved. The required submittal documentation shall also include “as-built” drawings of the installed postconstruction BMP, photographs, and other documentation listed in the Post-Construction BMP Installation Certification. The installation certification provided by the licensed Design Professional serves as an acknowledgement that the proposed stormwater BMP(s) have been installed in accordance with the approved stormwater management plan and other applicable provisions of this Manual. Stamped and signed “as-built” drawings shall be submitted in PDF format to the Planning Commission Engineer and accompanied with a compatible CAD file of the line work used in preparing these drawings.
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Upon final acceptance of the post-construction BMP and acknowledgement by the Planning Commission Engineer, responsibility for all related Stormwater Facility documentation shall be provided to the City Engineer for record keeping purposes. This documentation shall be used as reference material for longterm maintenance of post-construction stormwater BMPs through the Property Owner or Responsible Entity, e.g. Home Owners Association (HOA).
3.2. C Post-Construction Annual Inspection Once the post-construction BMPs are completed and deemed acceptable for their intended purpose by the Planning Commission Engineer, stormwater management controls for new development and redevelopment projects shall be inspected at least annually by the Property Owner or Responsible Entity. Requirements for these inspections shall be detailed in the Operations and Maintenance Agreement which calls for reporting to the City Engineer. General inspection requirements for each BMP are set forth in Chapter 5 of this BMP Manual. Annual post-construction inspection requirements for each stormwater BMP shall be governed by the Operations and Maintenance Agreement as approved and executed for each new development or redevelopment project. The template for this agreement is included in Appendix A of this Manual. Annual inspections shall be submitted using the inspection forms found in Section 5.2 for the specified BMP and/or following manufacturer’s recommendations as stated in the Operations and Maintenance Agreement for the project. Annual inspection forms and corresponding photographs shall be submitted to the City Engineer no later than September 30th, for each calendar year. The annual inspection requirement shall also apply to any new facilities placed into service on or before June 30th for a given calendar year. The City Engineer may impose additional inspection requirements for particular BMPs where circumstances warrant, and such additional requirements shall be incorporated into the Operations and Maintenance Agreement. The City may conduct periodic maintenance inspections of stormwater BMPs to verify compliance with the BMP Manual. The requirements for an annual inspection does not relieve the Property Owner or Responsible Entity from conducting any required maintenance that may arise throughout the course of a given calendar year. Annual inspection reports shall be maintained by the City Engineer for new and redevelopment projects that are regulated by these requirements.
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3.3
PERFORMANCE SECURITY The City may, at its discretion, require the submission of a performance security or bond before issuance of a land disturbance permit to ensure that the proposed stormwater facilities are installed as required by the approved Stormwater Management Plan. The amount of the installation performance security shall be the total estimated construction cost of the stormwater management facilities as outlined in the approved Stormwater Management Plan, plus 25 percent. The performance security shall acknowledge forfeiture as a consequence for failure to complete the work as specified in the approved Stormwater Management Plan. The installation performance security shall be released in full only upon submission of "as-built” drawings and written installation certification by a licensed Design Professional that the stormwater BMPs have been installed in accordance with the approved stormwater management plan and other applicable provisions of this Manual. One paper copy and electronic (PDF) copy of stamped and signed “as-built” drawings shall be submitted to the Planning Commission Engineer with a compatible CAD file of the line work used in preparing the drawings. Prior to release of the performance security, the Planning Commission Engineer shall make a final inspection of the stormwater BMP(s) to review compliance with the approved Stormwater Management Plan, and the provisions of this Manual. A partial pro rata release of the performance security based on the completion of various development stages may be permitted at the discretion of the Planning Commission Engineer.
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CHAPTER 4
Stormwater Management Design Criteria 4.1
APPROVED HYDROLOGIC ANALYSIS METHODS 4.1. A Design Storms The storm drainage system shall be designed to adequately handle the runoff from storms having various frequencies of occurrence from different types of development in accordance with the following general categories. To ensure the adequacy of the storm drainage system, the following minimum design storms shall be used, where applicable. Table 4.1-1 provides a summary of these requirements. 1. The 10-Year Storm shall be used for all public storm sewer inlets and closed pipe systems; as outlined in Section 4.5. 2. The 100-Year Storm shall be used for all public open channels and for pipe systems designed for a 10-Year Storm as a Check Storm to further ensure against damaging flooding or surcharging. 3. Channel linings should be designed to control the erosive flows resulting from the 100-Year Storm Event; as outlined in Section 4.7. 4. The 2-, 10-, 25- and 100-Year Storms shall be used to calculate pre- and post-development runoff from a site for detention and retention basins, as outlined in Section 4.2. 5. The 100-Year Storm shall be used for all detention, retention, or sediment control basins as a Check Storm to ensure against damaging flooding or surcharging. 6. The 100-Year Storm shall be used in the design of all culverts and bridge structures; as outlined in Section 4.6. 7. The 100-Year Storm shall be used in the design of flood control facilities. 8. The 100-Year Storm shall be used in comparison with established flood elevations from property owners, observations, Kentucky Transportation Cabinet (KYTC) drainage folder data, FEMA maps and other viable records to minimize the impacts of flooding and stormwater. 9. Additional controls or localized discharge restrictions may be placed on specific sites, as deemed necessary by the Planning Commission Engineer and/or City Engineer. For example, sites with pre-existing downstream problems where hydrologic and hydraulic models are developed for the area. Conditions for design in such cases shall be as required by the Planning Commission Engineer and/or City Engineer. 10. Sediment basins, if used, shall provide 3,600 cubic feet of storage per disturbed acre that drains to the facility in accordance with the Kentucky General Permit for Stormwater Point Discharges Associated with Construction Activities. When computer models are used to size sediment basins, the 10-year, 24-hour storm shall be used to determine sediment storage volumes and detention times. Table 4.1-1 Minimum Design Storms for Stormwater Management
STORM FREQUENCY 2 10 25 100
STORMWATER FACILITY Floodplains
Detention Basins
Inlets
Storm Sewers
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Culverts
Constructed Channels
Sediment Basins
4.1. B Runoff Computation Methods Numerous methods of rainfall-runoff computation are available on which the design of storm drainage and flood control systems may be based. The Rational Method and the Soil Conservation Service (SCS) hydrologic methods (available in TR-20, TR-55 and HEC-HMS) are accepted as adequate for determining peak runoff rates for drainage areas totaling 100 acres or less. For larger drainage systems, the SCS hydrologic methods or the USGS Regional Method of the Kentucky Transportation Cabinet, Department of Highways shall be used to determine peak runoff rates. The method of analysis must remain consistent when drainage areas are combined. The method, which applies to the largest combined drainage area should be used. The engineer may use other methods with prior approval by the Planning Commission Engineer. The Modified Rational Method (MRM) may be used for design of stormwater control facilities with a contributing drainage area to a stormwater control facility of ten acres or less.
4.1. C Rational Method The Rational Method may only be used to calculate peak discharge rates for drainage areas of 100 acres or less. The Rational Method shall not be used to calculate the volume of stormwater runoff or develop runoff hydrographs. Q = CiA where: Q = peak runoff quantity in cubic feet per second; C = runoff coefficient varying with the amount of imperviousness and other characteristics of the drainage area. Table 3 presents ranges for "C" values based on specific land use types; i = average intensity of precipitation in inches per hour, varying with frequency of storm occurrence, duration or concentration time, and area of the tributary watershed; A = area in acres of the tributary watershed. The rainfall intensity values shall be determined based on Table 4.1-2*. Interpolation may be used in determining intensities having unlisted times of concentration. Table 4.1-2 Rainfall Intensities
INTENSITY (INCHES/HOUR)
TIME OF CONCENTRATION (MINUTES)
2 YR.
10 YR.
25 YR.
100 YR.
10 15 30 60
4.13 3.38 2.28 1.40
5.41 4.46 3.11 1.99
6.10 5.04 3.58 2.33
7.12 5.91 4.30 2.89
Table values from the NOAA Atlas 14, Volume 2, Version 3: Point Precipitation Frequency Estimator for Kentucky, Georgetown Water Works Station ID: 15-3194.
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4.1. D Time of Concentration The time of concentration is the time associated with the travel of runoff from an outer point that best represents the shape of the contributing areas. Runoff from a drainage area usually reaches a peak at the time when the entire area is contributing, in which case the time of concentration is the time for a drop of water to flow from the hydraulically most remote point in the watershed to the point of interest. Runoff may reach a peak before the time the entire drainage area is contributing. Sound engineering judgment should be used to determine the time of concentration. The time of concentration to any point in a storm drainage system is a combination of the sheet flow (overland), the shallow concentrated flow and the channel flow, which includes storm sewers. The time of concentration shall be determined using the method described in Technical Release No. 55 published by the United States Department of Agriculture (USDA), NRCS. The overland flow method may be used to calculate the time of concentration for individual inlets with a contributing area of one (1) acre or less. When using the Rational Method, the minimum time of concentration for any area shall be 10 minutes.
4.1. E Runoff Coefficients When using the Rational Method, runoff coefficients (C) for the land uses shown in Table 4.1-3 must be used unless actual impervious areas are calculated and composite (C) factors are determined and submitted. When Composite (C) factors are used, impervious areas with a C = 0.95 and all other areas with a C = 0.40 shall be used. Table 4.1-3 Rational Method Runoff Coefficients for Composite Analysis
LAND USE DESCRIPTION Natural and Undisturbed Areas Single Family Residential Average Lot Size/Width 3 acres/300 feet 2 acres/200 feet 1 acre/100 feet 1/2 acre/ 100 feet 12,500 sq. ft./80 feet 9,000 sq. ft./40 feet 7,500 sq. ft./60 feet 6,000 sq. ft./50 feet <6,000 sq. ft./<50 feet Industrial Multi-Family Residential Commercial/ Office Impervious Areas Including; Pavement, Roofs, Drives. Sidewalks, etc.
AVERAGE PERCENT IMPERVIOUSNESS
RUNOFF COEFFICIENT (C)
Varies Varies (See Below for Value) 6 7 12 23 34 42 44 48 65 72 75 85
0.40 0.43-0.76 (See Below for Value) 0.43 0.44 0.47 0.53 0.59 0.63 0.64 0.66 0.76 0.80 0.81 0.87
100
0.95
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4.1. F Soil Conservation Service Method The SCS Method may be used to calculate the peak discharge rates; develop runoff hydrographs for basins and subbasins; determine runoff volumes; and provide inflow information to determine the required storage volume for detention and retention basins. The SCS Method is the preferred method for performing hydrologic analysis. The SCS Method will utilize the formulas, constants and data as currently provided by the NRCS. Technical Release 55 (TR-55), published by the NRCS provides methods of computation and constants for the SCS method, including runoff curve numbers, time of concentration, unit hydrographs and hydrologic soil group classifications. The SCS uses a 24-hour storm duration, which is considered to be acceptable for Georgetown and Scott County. When the Soil Conservation Service methods are used, the Type II rainfall distribution shall be used. The rainfall depths for the 24-hour storm are found in Table 4.1-4: Table 4.1-4 24-Hour Precipitation Depths
STORM FREQUENCY
24-HOUR RAINFALL DEPTH (IN)
2-YR 10-YR 25-YR 100-YR
2.97 4.28 5.15 6.68
Table values from the NOAA Atlas 14, Volume 2, Version 3: Point Precipitation Frequency Estimator for Kentucky, Georgetown Water Works Station ID: 15-3194.
For detailed information, the user is referred to the following Soil Conservation Service publications: 1. 2. 3. 4.
National Engineering Handbook (NEH) Section 4 Hydrology, Amendment 7; TR-20: Computer Program for Project Formulation, Hydrology; TR-55: Urban Hydrology for Small Watersheds; TP-149: A Method for Estimating Volume and Rate of Runoff in Small Watersheds.
4.1. G Kentucky Transportation Cabinet Method The USGS Regional Method of the KYTC, Department of Highways (Regional Method) may be used to calculate the peak discharge rates when required by regulatory agencies such as the Kentucky Division of Water. The Regional Method will use the formulas, constants and data from the current Drainage Guidance Manual, KYTC, Department of Highways.
4.1. H Modified Rational Method The Modified Rational Method (MRM) may be used for design of stormwater control facilities. The maximum contributing drainage area to a stormwater control facility designed with the MRM is 10 acres. If the MRM is used by computer program, the storm duration used shall be the one that produces the maximum storage. If calculating by hand, the duration shall be greater than the time of concentration.
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4.2
WATER QUANTITY DESIGN CRITERIA FOR NEW AND REDEVELOPMENT 4.2. A Quantity Impacts When land is developed, the hydrology, or the natural cycle of water is disrupted, altering the delivery of water and sediment to local waterways. Clearing removes the vegetation that intercepts, slows and returns rainfall to the air through evaporation and transpiration. Grading flattens hilly terrain and fills in natural depressions that slow and provide infiltration and temporary storage for rainfall. Rainfall that once seeped into the ground will move frequently off the surface. The addition of buildings, roadways, parking lots, and other surfaces that are impervious to rainfall further reduces infiltration and increases runoff. Depending on the magnitude of changes to the land surface, both the total runoff volume and magnitude can increase dramatically. These changes not only increase the total volume of runoff, but also accelerate the rate at which runoff flows across the land. This effect is further exacerbated by drainage systems such as gutters, storm sewers and lined channels that are designed to quickly carry runoff to rivers and streams. Development and impervious surfaces also reduce the amount of water that infiltrates into the soil and groundwater, thus reducing the amount of water that can recharge aquifers and feed streamflow during periods of dry weather. Land development alters the hydrology of watersheds and streams by disrupting the natural water cycle. This results in changes to stream flow, including increased runoff volumes and peak runoff discharges, greater runoff velocities, shorter time of concentrations, increased frequency of bankfull and near bankfull events, increase flooding, and lower dry weather base flows. The changes in the rates and amounts of runoff from developed watersheds directly affect the morphology, or physical shape and character, of Georgetown and Scott County’s streams and rivers. Some of the impacts because of development include stream widening and bank erosion, stream down-cutting, loss of riparian tree canopy, changes in the channel bed because of sedimentation, increase in the floodplain elevation. Along with changes in stream hydrology and morphology, the habitat value of streams diminishes because of development in a watershed. Impacts on habitat include degradation of habitat structure, loss of pool-riffle structure, increased stream temperature, and decline in abundance and biodiversity.
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4.2. B Peak Flow Design Criteria To minimize runoff damage to downstream properties, sediment pollution of public and private waters, and hydraulic overloading of existing drainage facilities, the peak stormwater discharge from a land disturbing activity or development and redevelopment activities after development shall not exceed the peak pre-development discharges as outlined below.
New Development Projects: Stormwater runoff control facilities shall be required on new development projects where necessary to reduce the peak flows to pre-development levels. The City may require additional detention where necessary to mitigate existing downstream flooding problems. These facilities may be designed and implemented for each individual site, but the use of regional facilities is encouraged. These shall be designed so that no standing water will remain in detention facilities during dry weather or that standing water in retention facilities will not be allowed to stagnate and present health hazards. Situations where detention may not be required are described in the following: 1. Detention may not be required on development sites that are part of a regional stormwater quantity masterplan. 2. Detention may not be required if the City has no documented downstream flooding problems and the Licensed Design Professional can demonstrate through a detailed watershed study that: o Undetained runoff will have no increase (0.00 feet) on downstream water surface elevations, or o Detention basins will increase flood elevations downstream due to the location of the detention basin in the watershed and the associated hydrograph timing effects. The procedures for demonstrating that detention is not needed are provided in the following: 1. The Licensed Design Professional shall conduct a watershed study to evaluate the impact on the drainage system (storm sewers and open channels) and receiving stream. The design storms shall be the flood control storms listed in Table 4.1-1 under Detention Basins. 2. The study area of the receiving stream shall extend downstream to a point where the proposed development represents less than 10 percent of the total watershed area draining to that point. 3. Detention may not be required if it can be shown that there is no increase (0.00 feet) in the water surface elevations within the study area for each of the design storms.
Redevelopment Projects: Redevelopment standards shall apply to parcels that were previously developed (e.g., contained structures or parking lots), where one acre or more of land will be disturbed, or areas less than one acre that are part of a larger common plan of development. Stormwater runoff control facilities are not required for redevelopment projects if there is no increase in impervious area. In situations where a redevelopment project results in a net increase in impervious area, stormwater controls shall be required to reduce peak flows to baseline conditions (i.e., the site imperviousness and stormwater controls present prior to demolition). The City may require additional controls where necessary to protect downstream property. Where impervious area is increased by 1 acre or greater, the redevelopment project shall follow the peak flow design criteria for new development.
New impervious area created by the construction of new roadways or the reconstruction of existing roadways is subject to the post-construction regulations for new development. Roadway reconstruction projects that do not increase impervious area are not subject to these regulations. 4–6
The amount of water to be detained shall be determined by the methods described in the following subsections using the design criteria as referenced in Section 4.1. The following subsections apply to all new development and redevelopment activities where applicable. 4.2. B.1 Detention/Retention Design Methods An accepted method that generates an inflow/outflow hydrograph such as the SCS method or MRM as detailed in Section 4.1 shall be used. It is required that a computer program be used to develop these hydrographs. All documentation shall be submitted for review by the Planning Commission Engineer. 4.2. B.2 Pre- and Post-Development Runoff Control The pre-development site runoff rate shall be calculated for the 2, 10, 25 and 100-Year Storm frequencies. The entire acreage contributing to the runoff shall be included in the calculations. The post-development site runoff rate shall be calculated for the ultimate development for the site based on the 2-, 10-, 25- and 100-Year frequency storm events. The entire acreage contributing to the runoff shall be included in the calculations. The post-development peak runoff rate shall be equal to or less than the pre-development peak runoff rate at any point of discharge for the ultimate development. 4.2. B.3 Storage Volume and Design Discharge The minimum basin storage volume shall be the difference between the post-development and pre-development 100-Year Storm inflow and outflow hydrographs or the volume necessary to sufficiently reduce post-development discharges to a rate needed to meet the capacity of existing culverts and drainage systems immediately downstream of the site proposed for development. If the basin is to be located directly on a portion of the through drainage system, volume calculations must also consider the total system flow reaching the basin. If the MRM is used by computer program, the storm duration used shall be the one that produces the maximum storage. The peak discharge from the storage facility shall be controlled by a release outlet structure and shall not be greater than a pre-developed peak runoff rate based on a 2-, 10-, 25- and 100-Year Storm frequency at that particular point where the discharge occurs. The outlet structure (including the emergency spillway) shall be sized to accommodate a flow equal to the 100-Year storm post-development discharge. The routing of the outlet structure (including the emergency spillway) shall be shown based on the 2-, 10-, 25- and 100-Year Storm frequency. Trash racks, or other techniques acceptable to the Planning Commission Engineer, shall be installed on the low flow outlet in detention basins to prevent clogging. KDOW hazard rated structures class A, B, and C require more stringent design criteria and will only be considered on a case by case basis by the Planning Commission Engineer.
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4.2. B.4 Design Standards These standards apply to permanent and temporary stormwater runoff, sediment and debris basins formed by an embankment or excavation. These standards are limited to the installation of basins on sites where failure of the structure will not result in loss of life, damage to adjacent properties, or interruption of use or service of public utilities; the area draining to the structure does not exceed 200 acres; and the water surface at the crest of the emergency spillway does not exceed five acres. 1. All basins shall be designed and built with side-slopes no greater than 3:1 (3 feet horizontal per 1 foot vertical). 2. Dry basins shall have a minimum 1 percent bottom drainage slope. For dry basins with bottom slopes less than 2 percent, a concrete channel is required. 3. Provide an emergency spillway sized to discharge the peak runoff from the 100-Year Storm assuming the principal spillway is clogged, without overtopping the dam crest. 4. The dam crest elevation shall not be less than one foot above the highest water surface elevation during the 100-Year event. 5. Discharge velocities within a pipe must be controlled to the same requirements as specified in Section 4.5. Erosion control linings for open channels must comply with the requirements in Section 4.7. 6. Stage, storage, discharge, and routing calculations for the 2-, 10-, 25- and 100-Year discharges must be submitted for review. 7. Detention basins shall be fully discharged within 36 hours of the end of the storm event. 8. Fencing may be required the Planning Commission Engineer when the location of the detention area is not easily observed or the side slopes of the basin are steeper than 4:1 (4 feet horizontal per 1 foot vertical). 9. Spillways shall be protected from erosion and shall employ energy dissipation, if necessary. 10. Stabilize earthen embankments immediately with temporary or permanent vegetation in accordance with requirements of the Kentucky BMP Manual for Construction Activities. 11. The engineer is required to include anti-seep collars where the spillway barrel passes through the embankment, baffles, and outlet protection. 12. Access for maintenance activities shall be provided from public or private right-of-way by establishing a drainage easement. Design the access to be at least 10 feet wide. Access way shall connect to the embankment so that equipment can access the top of the embankment on a slope not steeper than 5:1 (h:v). 13. Outlet works may be a combination of pipes, weirs, orifices and drop inlets, but design any outlet pipes to be at least 15 inches in diameter to facilitate maintenance. 14. If required by the KDOW, basins shall have dams and spillways that conform to the current Design Criteria for Dams and Associated Structures (Engineering Memorandum No. 5), KDOW. In cases when the top of the dam is also a publicly dedicated street right-of-way, the developer shall have a geo-technical report prepared with recommendations on the design and construction of the dam.
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4.2. B.5 Maintenance Responsibilities The property owner of a stormwater runoff control facility and/or the Responsible Entity of each subdivision shall be responsible for properly maintaining each stormwater runoff control facility in order for such facility to function according to its design and purpose. Maintenance responsibility and maintenance provisions for the facility shall be noted on the stormwater management plan and included in the Operations and Maintenance Agreement found in Appendix A of this Manual. Inspection forms for specific BMPs can be found in Chapter 5.2 at the end of each BMP fact sheet. The facility shall be shown on the Final Plat submitted to the Planning Commission Engineer. Maintenance necessary to maintain the function of detention facilities include:
Frequent removal of accumulated solids, debris, and litter from the detention/retention area, especially from the low flow channel. Accumulated sediments should be removed approximately once every two-five years depending on the contributing drainage area and land use. For retention basins, remove sediment when approximately 10 to 20 percent of the system’s storage volume has been lost. Removal of debris from vegetated areas to prevent damage to vegetation and to maintain visual appearance. Removal of debris from the bottom of the basin to reduce clogging of outlet structures, trash racks, and other mechanical components. Mowing. Removal of vegetation, such as small trees, which can damage the embankment. Structural repairs to inlets, outlets, or discharge structure, including the emergency spillway. Vegetative stabilization of eroding sides or bottom. Repairs to the dam, embankment, or slopes to prevent erosion or piping. Monitor channel erosion in downstream conveyances. Repairs to fences, if applicable.
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4.3
WATER QUALITY DESIGN CRITERIA FOR NEW AND REDEVELOPMENT 4.3. A Impacts to Water Quality Development and urbanization affect not only the quantity of stormwater runoff, but also its quality. Development increases both the concentration and types of pollutants carried by runoff. As it runs over rooftops and lawns, parking lots and industrial sites, stormwater picks up and transports a variety of contaminants and pollutants to downstream waterbodies. The cumulative loss of the original topsoil and vegetation also removes a valuable filtering mechanism for stormwater runoff. Nonpoint source (NPS) pollution, a primary cause of water quality impairment, is largely caused by polluted or poorly managed stormwater runoff. NPS pollution comes from many diffuse or scattered sources—most of which are the result of human activities within a watershed. Development concentrates and increases the amount of these nonpoint source pollutants. As stormwater runoff moves across the land surface, it picks up and carries away both natural and human-made pollutants, depositing them into streams, rivers, lakes, wetlands, and underground aquifers. The cumulative effect of nonpoint source pollution has become a leading source of water quality degradation. Erosion from poorly maintained construction sites and other disturbed areas contribute large amounts of sediment to streams. As construction and development proceed, impervious surfaces replace the natural land cover and pollutants from human activities begin to accumulate on these surfaces. During storm events, these pollutants are then washed off into the streams. Because of the magnitude of the problem, it is important to understand the nature and sources of stormwater pollution. Table 4.3-1 summarizes the major stormwater pollutants and their effects. Table 4.3-1 Summary of Urban Stormwater Pollutants
CONSTITUENTS
EFFECTS
Sediments–Suspended Solids, Dissolved Solids
Stream turbidity Habitat changes Recreation/aesthetic loss Contaminate transport Filling of lakes and reservoirs
Nutrients–Nitrate, Nitrite, Ammonia, Organic Nitrogen, Phosphate, Total Phosphorus
Algae blooms Eutrophication Ammonia and nitrate toxicity Recreation/aesthetic loss
Bacteria–Total and Fecal Coliforms, Fecal Streptococci Viruses, E. coli, Enterococci
Ear/Intestinal infections Shellfish bed closure Recreation/aesthetic loss
Organic Matter–Vegetation, Sewage, Other Oxygen Demanding Materials
Dissolved oxygen depletion Odors & Fish kills
Toxic Pollutants–Heavy Metals (cadmium, copper, lead, zinc), Organics, Hydrocarbons, Pesticides/Herbicides
Human & aquatic toxicity Bioaccumulation in the food chain Dissolved oxygen depletion Habitat changes Recreation/aesthetic loss
Thermal Pollution Trash and Debris 4 – 10
4.3. B Water Quality Volume Criteria In accordance with the KPDES permit for Phase II MS4 General Permit, Georgetown/Scott County have developed water quality treatment standards for new development and redevelopment projects that disturb one or more acres of land, or areas less than one acre that are part of a larger common plan of development. The following outlines the water quality treatment standard for each of these stormwater runoff producing activities.
New Development Projects: Based on the 90th percentile precipitation event, the runoff produced from the first 1 inch of rainfall must be passed through a water quality BMP before being discharged from the site. Rainfall records from the GMWSS water treatment plant shows that approximately 90 percent of total storm events occurred with 1 inch of rainfall or less; as shown in Figure 4.3-1.
Figure 4.3-1 Rainfall Frequency 1986-2001
Redevelopment Projects: Redevelopment standards shall apply to parcels that were previously developed (e.g., contained structures or parking lots), where one acre or more of land will be disturbed, or areas less than one acre that are part of a larger common plan of development. Reduce baseline or existing impervious area by 20 percent (based on historical maps or other documentation provided by the developer), or implement stormwater quality BMPs for 20 percent of the site impervious area, or a combination thereof. If the project results in a net increase in impervious area, stormwater quality BMPs shall be required for 20 percent of the existing impervious area plus 100 percent of the net increase in impervious area.
Post-construction stormwater runoff controls include a variety of water quality BMPs such as Infiltration practices, media filters, and water reuse. A list of pre-approved post-construction stormwater quality controls is included in Chapter 5 of the BMP Manual. Other post-construction stormwater quality controls may be implemented with explicit approval in writing from the Planning Commission Engineer.
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The following equation is used to determine the water quality volume needed to be treated for a development:
WQv = 1/12(P)(0.05+0.009.I)(A) WQV = Water quality volume, acre-ft. P = 90th percentile precipitation depth, 1 inch. I = Percent impervious, %. A = Total area of site, acre. The following Table 4.3-21 lists the amounts of impervious area that can be expected from different types of development, and the water quality depth in inches per given area: Table 4.3-2 Water Quality Depth based on Land Use
LAND USE/COVER TYPE
AVERAGE IMPERVIOUS COVER (%)
WATER QUALITY DEPTH (INCHES)
100 100 100 100 85 72 65 65 38 30 25 20 12
0.95 0.95 0.95 0.95 0.82 0.70 0.64 0.64 0.39 0.32 0.28 0.23 0.23
Paved parking lots2 Roofs Driveways Streets and roads2 Commercial and business districts Industrial Town houses Residential 1/8-acre lots or less Residential 1/4-acre lots Residential 1/3-acre lots Residential 1/2-acre lots Residential 1-acre lots Residential 2-acre lots 1Based
on NRCS TR-55 modeling criteria. right-of-way.
2Excluding
The required water quality volume must be accounted for by BMPs or in combination with appropriate stormwater credits. Groundwater recharge volumes can count towards the required water quality volumes; however, neither the groundwater recharge or water quality volumes are to be included in fulfilling the peak flow control portion of the stormwater regulations.
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4.3. C Targeted Pollutants New development or redevelopment projects that result in new or expanded flows to high quality waters (HQWs) shall provide the necessary BMPs that focus on removal of pollutants most common to the type of development occurring to maintain the level of water quality that protects existing uses of the receiving water body. Engineers are to use structural and non-structural BMPs as permitted by this Manual to treat the required water quality volume and maintain the level of water quality that protects existing uses of the receiving water. Individual treatments, or a combination of BMPs, can be used to achieve this goal. Different land uses can generate different types of runoff pollutants. For instance, a proposed refueling station would produce a higher concentration of hydrocarbons per acre than a proposed residential subdivision. Selection of BMPs should be based on the anticipated pollutants for a site. Some examples of typical pollutants for different land use applications are shown in Table 4.3-3: Table 4.3-3 Examples of Typical Pollutants for Different Land Use Applications
PATHOGENS
METALS
NUTRIENTS
PESTICIDES
ORGANIC COMPOUNDS (HYDROCARBONS, OIL & GREASE, SOLVENTS, PAHS)
SEDIMENT
TRASH & DEBRIS
OXYGEN DEMANDING SUBSTANCES (GREEN AND FOOD WASTE; SEWAGE)
CHLORIDE
HYDROMODIFICATION
POLLUTANT CATEGORY OF CONCERN
X
P(2)
X
X
X
X
X
X
P(5)
P
P(1)(3)
P
P(1)
P(1)
X
P(1)
X
P(1)(3)(4)
P(5)
P
P(1) P(1) X P(1)
X X P(2) X
P(1) P(1) P(1) P(1)
P(1) P(1) P(1) P(1)
X X X X
P P(1) P(1) P
X X X X
P(1)(3)(4) P(1)(4) X (1)(4) P
P P(5) P(5) P(5)
P P P P
X
X
X
P(1)(4)
P(5)
P
LAND USE
Residential Development Commercial/Industrial Development Industrial Areas Automotive Repair Shops Restaurants
Parking Lots Streets, Highways & P(1) X P(1) P(1) Freeways X = anticipated P = potential (1) A potential if chemicals associated with landscape maintenance such as fertilizers and pesticides are employed on site. (2) A potential pollutant if the project includes uncovered parking areas
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(3) A potential pollutant if land use involves food or animal waste products (4) A potential pollutant if sewer overflows, illicit sewage discharges, or septic systems exist (5) A potential pollutant if snow removal activities are performed
4.3. D Water Quality Credits Stormwater credits are reductions in the water quality volume calculations that are permitted through specific site design criteria. These credits are established to help reduce the impacts on Georgetown and Scott County’s stream systems. The credits are calculated based on the procedures outlined in Chapter 5 and subtracted from the water quality volume requirements for a development. The following is a list of the stormwater credits that are permitted for this community: 1. Vegetated filter strips 2. Riparian buffers 3. Terraformed Areas 4. Rooftop disconnections Note: Stormwater credits are set to encourage "greener" site designs and may be used in combination with required stormwater BMPs to treat the water quality volume. All drainage from proposed impervious areas must be treated by a stormwater BMP, unless otherwise authorized by the Planning Commission Engineer.
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4.4
GROUNDWATER RECHARGE DESIGN CRITERIA Base flows of local streams and waterways are fed by groundwater sources. Land development can cause changes in the contributing sources of water that support base flows. As the impervious area of a site increases, so does the volume of runoff. To maintain adequate base flows and stream ecosystems, developments must incorporate practices in their stormwater management plan to provide for groundwater recharge, where feasible. The amount of recharge that a site is capable of providing depends on topographic factors such as slope, types of vegetation, hydrologic soil groups, and locations of rock layers. The average annual recharge volume for a site can be estimated by taking the average annual recharge rate of the hydrologic soil group(s), dividing that by the average annual rainfall (44.05 inches), and then multiplying that result by 90 percent. The following Tables 4.4-1 and 4.4-2 provide a summary values used to calculate the natural groundwater recharge volume: Table 4.4-1 Soil Specific Recharge based on HSG Classification
HYDROLOGIC SOIL GROUP (HSG)
AVERAGE ANNUAL RECHARGE VOLUME in/yr
SOIL SPECIFIC RECHARGE (Sin) in
A B C D
18 12 6 3
0.37 0.25 0.12 0.06
Figure 4.4-1 Southern Scott County Soil Classifications
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Table 4.4-2 Scott County Soils
SOIL SERIES
NRCS HSG
DEPTH TO BEDROCK (ft)
SEASONAL HIGH WATER TABLE (ft)
PERMEABILITY (in/hr)
SUITABILITY AS ROAD FILL
Ashton
B
>4
>5
0.6-2.0
Fair
Cynthiana
D
1-1.5
>5
Dunning1
D
>3.5
0-0.5
Eden
C
1.5-3.5
>5
Faywood
C
1.5-3.5
>3.5
Huntington1
B
>4
>3
Lowell
C
>3.5
>5
Maury
B
>5
>5
McAfee
C
1.5-3.5
>3.5
Newark1
C,D
>4
0.5-1.5
0.6-2.0
Fair, Poor
Nicholson
C
>5
1.5-2.5
0.6-2.0 <0.2
Poor
Nolin1
B
4
3
0.6-2.0
Fair
D
-
-
-
-
Disturbed Soil
Note: S(in) = (S)(P). 1Subject to common flooding. References: 2000 Maryland Stormwater Design Manual Volumes I & II. Soil Survey of Scott County, Kentucky. Urban Hydrology for Small Watersheds, TR-55. LFUCG Stormwater Manual, 1999.
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0.6-2.0 0.2-0.6 0.6-2.0 <0.2 0.2-0.6 <0.2 0.6-2.0 2.0-6.0 0.6-2.0 0.6-2.0 0.2-0.6 0.6-6.0 0.6-2.0 0.6-2.0 0.2-0.6
Poor Poor Poor Poor Fair Poor Fair, Poor Poor
The soil specific recharge is determined by calculating a volume to be treated and infiltrated by a structural practice or by a percent area method involving a non-structural practice. The following formula shall be used for a structural practice:
GRv = 1/12(Sin)(0.05+0.009.I)(A) GRV = Groundwater recharge volume, acre-ft. Sin = Soil specific recharge, in. I = Percent impervious, %. A = Total area of site, acre. Examples of structural practices that can be used for groundwater recharge are bioretention areas, infiltration facilities, terraformed berms, and infiltration swales and are to be inspected during construction and added to the list of BMPs to be maintained for the property. The use of infiltration facilities commonly referred to as “rock trenches” constructed at the outlet of roof drains on single family detached developments including duplexes do not count towards the groundwater recharge volume. Since Scott County is in a karst region, engineers that intend to use structural practices for groundwater recharge must evaluate potential areas to ensure that these proposed facilities would be appropriate and not have an adverse impact on surrounding areas, such as increasing the water table. Engineers are to ensure the groundwater recharge facility is designed to naturally infiltrate the groundwater recharge volume. If groundwater recharge facilities are designed with an overflow system (e.g. underdrain), the system shall provide water quality treatment that meets the requirements of Chapter 4.3 before the discharge leaves the site. Dewatering times for structural practices should not exceed 48 hours. Groundwater recharge requirements may be waived for redevelopments only if approved by the Planning Commission Engineer. Site soil testing is required and shall be provided to the Planning Commission Engineer if positive outflow is not provided to indicate that existing soils will infiltrate the groundwater recharge volume.
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4.5
STORM SEWER SYSTEM DESIGN CRITERIA Proposed storm sewer systems that are located within the public right-of-way or systems within drainage easements in Georgetown and Scott County must adhere to the following guidelines:
All proposed storm lines are to be reinforced concrete pipe (RCP), high density polyethylene pipe (HDPE), or polyvinyl chloride (PVC) that adhere to the following design criteria and are selected and installed per KYTC Standard Specifications and Drawings:
Reinforced Concrete Pipe (RCP) shall be produced in accordance to AASHTO M170, Class III, IV, or V. Non-reinforce concrete pipe is not acceptable. RCP shall be installed per KYTC Standard Specifications and Drawings. Additional installation and handling guidelines can be acquired from the American Concrete Pipe Association (www.concrete-pipe.org).
Corrugated Plastic Pipe (or HDPE) shall be produced in accordance to AASHTO M294, Type S for diameter sizes 15 inches through 60 inches. No HDPE pipe using recycled resin is to be used. HDPE pipe shall be installed per KYTC Standard Specifications and Drawings. Additional installation and handling guidelines can be acquired from the Plastic Pipe Institute (www.plasticpipe.org).
Polyvinyl Chloride Pipe (PVC) shall be produced in accordance to AASHTO M304. PVC pipe shall be installed per KYTC Standard Specifications and Drawings. Additional installation and handling guidelines can be acquired from the PVC Pipe Association (www.uni-bell.org).
Corrugated Metal Pipe (CMP) shall be produced in accordance to ASSHTO M36, aluminized steel Type 2. No galvanized CMP is accepted. Aluminized Type 2 CMP shall be installed per KYTC Standard Specifications and Drawings.
Minimum pipe diameter for proposed lines is 15 inches.
Space storm sewer structures no more than 300 feet apart for pipes 48-inch diameter or less, and no more than 400 feet apart for pipes 54-inch diameter or larger.
Bedding details and joint specifications are to be provided with all construction drawings and shall comply with manufacturer’s recommendations.
A storm sewer structure must be placed at the following locations:
where the proposed storm sewer extends beyond the maximum length
where there is a change in horizontal or vertical alignment
where the pipe material changes
at the beginning and ending points for proposed storm lines
Proposed systems are to be designed to handle the 10-Year Storm event capacity with the HGL below the crown of pipe. Flow interception for structures must be based on bypass conditions. No proposed system will be permitted to surcharge in the 100-Year Storm event.
Engineers are to design storm sewers to prevent the 100-Year Storm event from crossing roadway crowns for local and continuous streets.
Curb inlets are to be spaced on grade to limit spread of water to 6 feet from the edge of roadway pavement for widths of 24 feet or greater, excluding curb and gutter. Spread calculations are to be based on an intensity of four (4) inches/hour. For roadway pavement widths less than 24 feet, a minimum of 6 feet of the vehicular travel lane must be free of spread of water. The Planning Commission Engineer may require a reduction in allowable spread based on traffic volume and speed limit.
100-Year water surface elevations are to be determined for all proposed storm sewer structures, including headwalls and surface inlets.
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In residential subdivisions that include curb and gutter as part of their roadway design, proposed storm lines that leave the street right-of-way are to be daylighted at the rear lot line.
Overflow swales are to be provided at sag locations in commercial and residential subdivisions with appropriate easements and restrictions on the Final Subdivision Plat. Overflow swales shall be designed to carry the 100-year Storm in the event of a storm sewer blockage.
Private systems are allowed to discharge stormwater into the City’s storm sewer system only after the proper water quality, quantity and recharge treatments have been met. Treated stormwater that has mixed with untreated stormwater must be retreated before discharge into the City’s storm sewer system.
The Planning Commission Engineer must approve the types of structures proposed for stormwater systems in the right-of-way or within drainage easements. The following requirements apply:
Curbs are to be installed as box type curb and gutter
Curb inlet boxes are not the have a grate in the gutter line, unless otherwise approved by the Planning Commission Engineer
Structures are to include access for maintenance and inspection
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4.6
CULVERT AND BRIDGE DESIGN CRITERIA Proposed channel and stream crossings are to include a means to convey the 100-year flow. Culverts are typically used in situations where drainage ways do not have any base flows associated with them. Head conditions occur on the upstream side to force the peak flow through the structure(s). Proposed culverts are to be designed so that the 100-year water surface elevation is a minimum of one foot below the overtopping elevation of any embankment, road, ditch, etc. Bridge structures are to be used at creek and stream crossings where base flow conditions do exist (base flow being defined as water being present in channel and stream areas during dry weather conditions). These structures are to be designed to convey the 100-year flow rate unimpeded, and allow the 100-year water surface elevation to be one foot below the bottom of the bridge super structure. After construction, the stamping professional engineer shall inspect and certify all bridges as required in the stormwater management plan. Prior to plan approval all permits are to be obtained from USACE and/or KDOW, if applicable, and provided to the Planning Commission Engineer. Other design considerations that apply to culverts and bridges are listed in the following:
Live load considerations for anticipated construction traffic, fire service vehicles, refuse trucks, commercial vehicles, etc.
Public protection for pedestrian and bicycle traffic, if applicable.
Headwalls for the upstream and downstream sides of proposed culverts. Fences or railing are to be provided for headwall that are for 30-inch lines or greater.
Railing design for bridges.
End treatments for culverts to minimize erosion and sediment transport.
Scouring protection for bridge piers and abutments.
Fish passage.
Streambank stabilization designs for backwater areas and accelerated flows downstream.
There are areas within Scott County, particularly in the north, where existing roadways are already in place and are within the regulatory floodplain. In situations where roads must be improved because of development, any portion of the roadway that is flooded by the 100-Year Event or less must be reconstructed to provide a concrete cap with a turned down slab on the upstream side to reduce the potential of a roadway being washed out.
4 – 20
4.7
OPEN CHANNEL DESIGN CRITERIA 4.7. A Design Standards Open channels provide many advantages in the management and control of stormwater runoff. Such channels provide for natural infiltration of stormwater into the ground water supply and can extend the Time of Concentration (Tc) helping to maintain the runoff rate nearer to that which existed prior to development. The objective of open channel flow design is: (a) to determine a channel slope and size that will have sufficient capacity to prevent undue flooding damage during the anticipated peak runoff period; and (b) to determine the degree of protection based on stream velocity to prevent erosion in the drainage channel. Existing drainage channels, which will remain undisturbed, shall not be required to be reconstructed unless additional capacity and stabilization is required. Developments that use open channels to convey runoff must adhere to the following guidelines:
Convey the 100-year Storm Event.
Designs not to exceed the channel lining’s critical shear force and permissible velocity in the 100-year Storm Event.
Select the appropriate roughness values for proposed channels.
Provide any armoring needed for hydraulic jump and bend conditions.
Earthen channel side slopes shall be no steeper than 2:1. Open channels with lining shall have a maximum gradient on side slopes of 3:1.
Design velocities should generally be greater than 1.5 feet per second to avoid excessive deposition of sediments. When flat slopes are unavoidable, concrete paving should be used to accelerate runoff.
Erosion shall be controlled by limiting velocities, changing the channel lining or reshaping the channel to spread the flow of runoff. Methods of controlling erosion in open channels include the following: (1) grass covers or sod; (2) aggregate channel lining; (3) geo-textile turf reinforcement mats (TRMs) and rolled erosion control products (RECPs); and (4) reinforced concrete or pre-cast paving (5) bioengineering practices. Channel linings should be designed to control erosive flows resulting from the 100-Year Storm Event. The design of channel linings should meet both the velocity and shear stress requirements. Consideration shall be given for the construction of other methods of lining for erosion control including check dams, drop structures, gabions, etc. subject to approval of the Planning Commission Engineer. Constructed channels in residential areas that receive runoff from a storm sewer or culvert shall be designed with a low flow channel constructed of permanent turf reinforcement, permeable pavers, or articulated blocks to prevent erosion. Concrete low flow channels may only be used if the above methods are not sufficient to prevent erosion. The low flow channel shall be designed to carry 25 percent of the 10-Year Storm.
4 – 21
4.7. B Manning’s Equation Use Manning Equation to design open channels.
Q = (1.49/n)AR2/3 S1/2 Q = discharge, cfs n = Manning’s roughness coefficient A = cross-sectional area of flow, ft2 R = hydraulic radius = A/P, ft P = wetted perimeter, ft S = channel slope, ft/ft Select Manning’s n from Table 4.7-1. Table 4.7-1 Manning’s n for Constructed Channels
LINING TYPE
MANNING’S n
Concrete Grouted Stone Stone Masonry
0.013 0.030 0.032
Bare Soil Rock Cut
0.020 0.035
Jute Net Straw with Net Curled Wood Mat
0.022 0.033 0.035
6-inch D50 Riprap 12-inch D50 Riprap
0.050 0.060
Grass
0.045
Streams
0.045
Floodplains Pasture, no brush Brush Trees
0.035 0.10 0.120
4 – 22
4.8
OFF-SITE MITIGATION It is the intent of the City and GSCPC to ensure post-construction stormwater management regulations are enforced to reduce the impact of development on the public drainage system and the environment. The off-site mitigation option is available for the following situations: 1. The developer cannot meet the post-construction requirements due to site restrictions or unreasonable financial burden; or 2. The developer identifies an off-site control that is more beneficial or effective than the site-level control that would be required by the post-construction stormwater requirements. To request approval for a proposed off-site mitigation project alternative, the owner/developer must notify the Planning Commission Engineer in writing and provide the following information:
Explanation of why post-construction stormwater management standards may not be met on-site.
Identification of the off-site mitigation project that will be completed in lieu of implementing post construction controls on-site. Explanation of approach for long-term maintenance and upkeep of the completed off-site controls.
If the project site discharges to a waterbody with a TMDL allowance as defined and designated by KDOW, the provisions of this policy may not be applicable. Projects that discharge to waterbodies with a TMDL will be evaluated on a case-by-case basis. The owner/developer must contact the Planning Commission Engineer to determine if off-site mitigation is an appropriate alternative. Off-site mitigation can be completed for all or a portion of the amount of stormwater required to be managed onsite. The following outlines the criteria for off-site mitigation: 1) The owner/developer must identify an off-site mitigation project of equal stormwater benefit (based on requirements of post-construction water quality treatment standard) in the same sub-watershed as the project. Stormwater benefit of an off-site mitigation project will be based upon land cover; off-site mitigation project must address similar types of land cover as that of the development project. For example, an off-site mitigation project for one acre of impervious area must address the stormwater runoff generated from at least one acre of impervious area off-site. 2) If the owner/developer and the Planning Commission Engineer cannot agree upon a project within the same sub-watershed, the Planning Commission Engineer may consider allowing off-site mitigation within the same watershed. Projects will be evaluated based upon impacts to the receiving waterbodies. The owner or authorized representative must demonstrate that the mitigation project provides equivalent water quality benefits and equally protects water quality of the receiving waters as would have been provided by the post-construction water quality treatment standard for the development or re-development project. 3) The owner or authorized representative must implement an Operations and Maintenance Agreement with the City detailing how long-term maintenance and up-keep for the completed off-site control will be implemented.
4 – 23
CHAPTER 5 Stormwater BMP Fact Sheets 5.1
OPTIONS FOR STORMWATER MANAGEMENT Table 5.1-1 Best Management Practices for Residential and Commercial/Industrial Developments
RESIDENTIAL DEVELOPMENT BEST MANAGEMENT PRACTICES QUANTITY
QUALITY
COMMERCIAL AND INDUSTRIAL DEVELOPMENT QUANTITY
Bioretention/ Rain Gardens
QUALITY
Bioinfiltration Swales 2
Permeable Pavement
Extended Detention Basin
Wet Ponds
Prefabricated Devices1
Sand Filters Constructed Wetlands
Vegetative Filter Strips
Riparian Buffers
Terraforming Rooftop Disconnections
Vegetated Channels
1Prefabricated
devices includes Gravity Separators for quality control and Subsurface Vaults for quantity control. 2Permeable Pavement may be permitted for multi-family and mixed use residential applications only.
5–1
5.2
APPROVED BMP FACT SHEETS The purpose of the BMP Fact Sheets is to provide guidance on the site suitability, design requirements, and sizing standards for quantity and quality control BMPs. The following BMPs are included in this chapter:
5.2.A Bioretention/Rain Gardens 5.2.B Bioinfiltration Swales 5.2.C Permeable Pavement 5.2.D Extended Detention Basins 5.2.E Wet Ponds 5.2.F Prefabricated Devices 5.2.G Sand Filters 5.2.H Constructed Wetlands 5.2.I
Vegetated Filter Strips
5.2.J
Riparian Buffers
5.2.K Terraforming 5.2.L
Rooftop Disconnections
5.2.M Vegetated Channels Each BMP Fact Sheet provides the following information:
Description
Site Suitability
Design Criteria
Design Procedure
Design Schematics
Maintenance Considerations
Typical Inspection Checklist
5–2
REFER TO BMP FACT SHEETS (provided separately)
5–3
APPENDICES Appendix A LONG-TERM O&M AGREEMENT As stipulated by the USEPA’s Phase II Stormwater regulations, the City must require that the owners of all new development and redevelopment property enter into a long-term operations and maintenance agreement with the City for the perpetual maintenance and upkeep of stormwater management facilities, including post-construction BMP(s). This agreement shall include a written maintenance program and requires the Property Owner or Responsible Entity to complete the following:
Perform periodic inspection(s) and complete required routine maintenance and structural repairs. Complete an annual self-inspection and submit documentation to the City Engineer by September 30th of each calendar year.
The agreement shall include provisions that will allow the City to conduct independent inspections of the post-construction stormwater controls. If during the City inspection process, deficiencies are found, the City shall notify the Property Owner or Responsible Entity of the deficiencies and perform a follow-up inspection to ensure that the required repairs are completed. Failure on the part of the City to notify the Property Owner or Responsible Entity does not relieve the property owner of the maintenance responsibilities outlined within the Operation and Maintenance Agreement. If repairs are not made, the Phase II Stormwater Regulations require that the City to enforce correction orders, and if necessary, perform the needed work and assess against the owner, the costs incurred for repairs.
A–1
STORMWATER MANAGEMENT/ BMP FACILITIES OPERATIONS AND MAINTENANCE AGREEMENT
City of Georgetown, KY
(502) 863-9800
STORMWATER MANAGEMENT/BMP FACILITIES OPERATIONS AND MAINTENANCE AGREEMENT For Commercial Property THIS AGREEMENT, made and entered into this ___ day of ____________, 20___, by and between (Insert Full Name of Owner(s) of the property) ________ ___________ ___________ _______________ ___________ hereinafter collectively called the "Landowner," and the City of Georgetown, hereinafter called the "City". WITNESSETH WHEREAS, Landowner is the owner of certain real property described as (Scott County tax Map/Parcel Identification Number) ___________________________________ __________ as recorded by deed in the land records of Scott County, Kentucky, Deed Book __________ Page __________, hereinafter called the "Property”; and WHEREAS, the Landowner is proceeding to build on and develop the Property for commercial use; and WHEREAS, the Stormwater Management Plan (hereinafter the “Stormwater Plan”) approved as part of the Subdivision Development Plan for the subdivision in which the property is located, and which is attached hereto as Exhibit A and expressly made a part hereof, as approved or to be approved by the City, provides for detention and/or treatment of stormwater within the confines of the property; and WHEREAS, the City and the Landowner and its successors and assigns agree that the health, safety, and welfare of the residents of Georgetown, Kentucky require that on-site stormwater management/BMP facilities (hereinafter “BMP” or “BMPs”) be constructed and maintained on the Property; and WHEREAS, City Ordinance # 2015-001 requires that responsibility for BMP operation and maintenance in new commercial developments and redevelopments containing BMPs shall be governed by a separate legal entity sufficient to operate, maintain and provide for the revenue necessary to operate and maintain the BMPs on behalf of owners of individual lots in the development, unless the City waives the requirement of having a separate legal entity; and
WHEREAS, the City has determined that it is appropriate to waive the requirement of having a separate legal entity govern the responsibilities imposed under Ordinance 2015-001 for this development; and WHEREAS, Landowner has filed a Declaration of Covenants and Restrictions in Miscellaneous Book ___ Page ___, which is attached hereto as Exhibit B and incorporated as though set forth fully herein, which Covenants and Restrictions perpetually bind the Property to the maintenance and operation of the BMPs constructed on the Property as required by Ordinance 2015-001; NOW, THEREFORE, in consideration of the foregoing premises, the mutual covenants contained herein, and the following terms and conditions, the parties hereto agree as follows: 1.
Each and every owner and successive owner of all or a portion of the Property, including
the Landowner, and his or her successors and assigns shall be considered a Responsible Entity as that term is defined in City Ordinance 15-001 and shall be expressly subject to the terms and conditions of this Agreement. 2.
The Responsible Entities and their successors and assigns shall bear responsibility to
adequately maintain the BMPs according to the requirements of Ordinance 2015-001, the City of Georgetown Stormwater BMP Manual (hereinafter the “BMP Manual”) and the Stormwater Plan. This maintenance responsibility shall be apportioned to each Responsible Entity based on the number of lots owned by the individual Responsible Entity over the total number of lots whose stormwater runoff is controlled or treated by the BMPs as specified in the Stormwater Plan. For example: If the Landowner owns 10 out of 10 lots whose stormwater runoff is controlled or treated by a BMP, he or she shall bear 100% of the responsibility for maintenance and operation of the BMP. If the Landowner sells 5 lots to individual owners, the Landowner shall bear 50% responsibility and each new lot owner shall bear 10%. Nothing in this section shall prohibit the owners of property subject to this Agreement from entering into an agreement amongst themselves regarding equitable allocation of costs for operation and maintenance of BMPs. Any such agreement, however, shall not alter the proportionate responsibility provision of this Agreement.
3.
Adequate maintenance is herein defined as good working condition so that these facilities
are performing their designed functions. The Responsible Entities and their successors and assigns shall maintain each BMP subject to this Agreement according to the specifications, inspection and maintenance checklists and maintenance schedules set forth in the BMP Manual. The applicable inspection schedules and maintenance checklists, including any manufacturerprovided schedules for the Property are attached hereto as Exhibit C and incorporated herein. The City reserves the right to amend or alter the requirements of the BMP Manual at any time. The Annual Inspection Report in the BMP Manual shall be consulted to determine whether the working condition of the BMPs is acceptable to the City. The City shall have the sole discretion and authority to determine whether the BMPs are in acceptable condition. 4.
The Responsible Entities and their successors and assigns shall inspect the BMPs and
submit an inspection report annually, no later than September 30th. The purpose of the inspection is to assure safe and proper functioning of the facilities. The inspection shall cover the entire facilities, berms, outlet structure, pond areas, access roads, etc. Deficiencies shall be noted in the inspection report. 5.
The Responsible Entities and their successors and assigns hereby grant permission to the
City and its authorized agents and employees, to enter upon the Property and to inspect the BMPs whenever the City deems necessary. The purpose of inspection is to follow-up on reported deficiencies and/or to respond to citizen complaints. The City shall provide the Responsible Entity, its successors and assigns, copies of the inspection findings and a directive to commence with the repairs if necessary. 6.
Pursuant to City of Georgetown Ordinance 2015-001 and this Agreement, in the event the
Responsible Entities and/or their successors and assigns fail to maintain the BMPs in good working condition acceptable to the City, the City may, after satisfaction of any applicable notice and appeal requirements in the ordinance, enter upon the Property and take any and all steps necessary to correct deficiencies identified in the inspection report and to charge the costs of such repairs to the Responsible Entities and their successors and assigns. This provision shall not be construed to allow the City to erect any structure of permanent nature on the land of the Responsible Entities outside of the easement(s) for the BMPs. The parties expressly understand
and agree that the City is under no obligation to routinely maintain or repair said facilities, and in no event shall this Agreement be construed to impose any such obligation on the City. 7.
The Responsible Entities and their successors and assigns shall perform the work necessary
to keep the BMPs in good working order as appropriate. In the event a maintenance schedule for the BMPs (including sediment removal) is outlined on the approved Stormwater Plan, the schedule shall be followed. 8.
In the event the City, pursuant to City of Georgetown Ordinance 2015-001 and/or this
Agreement, performs work of any nature or expends any funds in performance of said work for labor, use of equipment, supplies, materials, and the like, the Responsible Entities and their successors and assigns shall reimburse the City upon demand, within thirty (30) days of receipt thereof for all actual costs incurred by the City hereunder. The City shall possess a lien upon the property for all such costs. 9.
This Agreement imposes no liability of any kind whatsoever on the City, and the
Responsible Entities and their successors and assigns agree to hold the City harmless from any liability in the event the BMPs fail to operate properly. 10.
This Agreement shall be recorded among the land records of Scott County, Kentucky, and
shall constitute a covenant running with the land against the Property and shall be binding on the Responsible Entities and their administrators, executors, assigns, heirs and any other successors in interest, and the individual owners of any subdivided lots and their administrators, executors, assigns, heirs and any other successors. 11.
This Agreement shall not be amended absent the written authorization of all parties.
WITNESS the following signatures and seals:
_____________________________________________ Landowner 1 (add as many as necessary to include all owners of the Property at time of execution) _____________________________________________
Printed Name_____________________________________________ Title STATE OF ______________________
COUNTY OF ____________________ The foregoing Agreement was acknowledged before me this ____ day of ____________, 20___, by (Landowner name) ________________________________________________ NOTARY PUBLIC My Commission Expires: ____________ CITY OF GEORGETOWN, KENTUCKY _____________________________________________ Mayor_____________________________________________ Printed name STATE OF ______________________
COUNTY OF ____________________ The foregoing Agreement was acknowledged before me this ____ day of ____________, 20___, by (Responsible Entity name) ______________________________________________ NOTARY PUBLIC My Commission Expires: ____________
This Document was prepared by: Andrew S. Hartley City Attorney 100 North Court Street Georgetown, KY 40324 502-863-9800
_________________________________
___________ Date
Exhibit A:
Stormwater Management Plan
Exhibit B:
Declaration of Covenants and Restrictions
Exhibit C:
BMP maintenance Schedules and Checklists
Exhibit D:
BMP drawings and photographs
STORMWATER MANAGEMENT/ BMP FACILITIES OPERATIONS AND MAINTENANCE AGREEMENT
City of Georgetown, KY
(502) 863-9800
STORMWATER MANAGEMENT/BMP FACILITIES OPERATIONS AND MAINTENANCE AGREEMENT
THIS AGREEMENT, made and entered into this ___ day of ____________, 20___, by and between (Insert Full Name of Owner(s)) ________________ _____________________________ ________ ___ hereinafter collectively called the "Landowner," (insert name of HOA)___________ ____________ hereinafter called the “Responsible Entity” and the City of Georgetown, hereinafter called the "City". WITNESSETH WHEREAS, Landowner is the owner of certain real property described as (Scott County tax Map/Parcel Identification Number) ___________________________________ __________ as recorded by deed in the land records of Scott County, Kentucky, Deed Book __________ Page __________, hereinafter called the "Property”; and WHEREAS, the Landowner is proceeding to build on and develop the Property; and WHEREAS, the Stormwater Management Plan (hereinafter the “Stormwater Plan”) approved as part of the Subdivision Development Plan for the subdivision in which the property is located, and which is attached hereto as Exhibit A and expressly made a part hereof, as approved or to be approved by the City, provides for detention and/or treatment of stormwater within the confines of the property; and WHEREAS, the City, Landowner and the Responsible Entity and their successors and assigns agree that the health, safety, and welfare of the residents of Georgetown, Kentucky require that on-site stormwater management/BMP facilities (hereinafter “BMP” or “BMPs”) be constructed and maintained on the Property; and WHEREAS, City Ordinance # 2015-001 requires that responsibility for BMP operation and maintenance in new residential developments and redevelopments containing BMPs shall be governed by a separate legal entity such as a homeowner’s association, sufficient to operate, maintain and provide for the revenue necessary to operate and maintain the BMPs on behalf of owners of individual lots in the subdivision; and
WHEREAS, Landowner has designated, in the Declaration of Covenants and Restrictions filed in Miscellaneous Book ___ Page ___, which are attached hereto as Exhibit B and incorporated as though set forth fully herein, (HOA name) as the Responsible Entity responsible for operation of maintenance of the BMPs. NOW, THEREFORE, in consideration of the foregoing premises, the mutual covenants contained herein, and the following terms and conditions, the parties hereto agree as follows: 1.
The Responsible Entity and its successors and assigns shall bear responsibility to
adequately maintain the BMPs according to the requirements of Ordinance 2015-001, the City of Georgetown Stormwater BMP Manual (hereinafter the “BMP Manual”) and the Stormwater Plan. The Responsible Entity shall apportion this maintenance responsibility to each individual owner of a subdivided lot or lots, including the Landowner, based on the number of lots owned by the individual owner over the total number of lots whose stormwater runoff is controlled or treated by the BMPs as specified in the Stormwater Plan. For example: If the Landowner owns 10 out of 10 lots whose stormwater runoff is controlled or treated by a BMP, he or she shall bear, by and through his or her obligation to the Responsible Entity, 100% of the responsibility for maintenance and operation of the BMP. If the Landowner sells 5 lots to individual owners, the Landowner shall bear 50% responsibility and each new lot owner shall bear 10%. 2.
Adequate maintenance is herein defined as good working condition so that these facilities
are performing their designed functions. The Responsible Entity and its successors and assigns shall maintain each BMP subject to this Agreement according to the specifications, inspection and maintenance checklists and maintenance schedules set forth in the BMP Manual. The applicable inspection schedules and maintenance checklists, including any manufacturer-provided schedules for the Property are attached hereto as Exhibit C and incorporated herein. The City reserves the right to amend or alter the requirements of the BMP Manual at any time. The Annual Inspection Report in the BMP Manual shall be consulted to determine whether the working condition of the BMPs is acceptable to the City. The City shall have the sole discretion and authority to determine whether the BMPs are in acceptable condition. 3.
The Responsible Entity and its successors and assigns shall inspect the BMPs and submit an
inspection report annually, no later than September 30th. The purpose of the inspection is to assure safe and proper functioning of the facilities. The inspection shall cover the entire facilities, berms, outlet structure, pond areas, access roads, etc. Deficiencies shall be noted in the inspection report. 4.
The Responsible Entity and its successors and assigns hereby grant permission to the City
and its authorized agents and employees, to enter upon the Property and to inspect the BMPs whenever the City deems necessary. The purpose of inspection is to follow-up on reported deficiencies and/or to respond to citizen complaints. The City shall provide the Responsible Entity, its successors and assigns, copies of the inspection findings and a directive to commence with the repairs if necessary. 5.
Pursuant to City of Georgetown Ordinance 2015-001 and this Agreement, in the event the
Responsible Entity and/or its successors and assigns fails to maintain the BMPs in good working condition acceptable to the City, the City may, after satisfaction of any applicable notice and appeal requirements in the ordinance, enter upon the Property and take any and all steps necessary to correct deficiencies identified in the inspection report and to charge the costs of such repairs to the Responsible Entity and its successors and assigns. This provision shall not be construed to allow the City to erect any structure of permanent nature on the land of the Responsible Entity outside of the easement(s) for the BMPs. The parties expressly understand and agree that the City is under no obligation to routinely maintain or repair said facilities, and in no event shall this Agreement be construed to impose any such obligation on the City. 6.
The Responsible Entity and its successors and assigns shall perform the work necessary to
keep the BMPs in good working order as appropriate. In the event a maintenance schedule for the BMPs (including sediment removal) is outlined on the approved Stormwater Plan, the schedule shall be followed. 7.
As required by Ordinance 2015-001, the Responsible Entity shall govern the maintenance
and operation responsibility on behalf of the Responsible Entity and its successors and assigns, including future owners of subdivided lots, by: a) Levying fees upon Responsible Entity and its successors and assigns sufficient to defray
the costs of operating and maintaining the BMPs as required by Ordinance 2015-001 and this Agreement, including the costs owed to the City for any necessary remediation work. b) Maintaining, operating and inspecting BMPs. c) Submitting inspection reports to the City. 8.
In the event the City, pursuant to City of Georgetown Ordinance 2015-001 and/or this
Agreement, performs work of any nature or expends any funds in performance of said work for labor, use of equipment, supplies, materials, and the like, the Responsible Entity and its successors and assigns shall reimburse the City upon demand, within thirty (30) days of receipt thereof for all actual costs incurred by the City hereunder. The City shall possess a lien upon the property for all such costs. 9.
This Agreement imposes no liability of any kind whatsoever on the City, and the
Responsible Entity and its successors and assigns agree to hold the City harmless from any liability in the event the BMPs fail to operate properly. 10.
This Agreement shall be recorded among the land records of Scott County, Kentucky, and
shall constitute a covenant running with the land against the Property and shall be binding on the Responsible Entity and its administrators, executors, assigns, heirs and any other successors in interest, and the individual owners of any subdivided lots and their administrators, executors, assigns, heirs and any other successors. 11.
This Agreement shall not be amended absent the written authorization of all parties.
WITNESS the following signatures and seals:
_____________________________________________ Landowner _____________________________________________ Printed Name_____________________________________________
Title STATE OF ______________________
COUNTY OF ____________________ The foregoing Agreement was acknowledged before me this ____ day of ____________, 20___, by (Landowner name) ________________________________________________ NOTARY PUBLIC My Commission Expires: ____________
_____________________________________________ Responsible Entity _____________________________________________ Printed Name of Representative _____________________________________________ Title STATE OF ______________________
COUNTY OF ____________________ The foregoing Agreement was acknowledged before me this ____ day of ____________, 20___, by (Responsible Entity name) ______________________________________________ NOTARY PUBLIC My Commission Expires: ____________
CITY OF GEORGETOWN, KENTUCKY _____________________________________________ Mayor_____________________________________________ Printed name
STATE OF ______________________
COUNTY OF ____________________ The foregoing Agreement was acknowledged before me this ____ day of ____________, 20___, by (Responsible Entity name) ______________________________________________ NOTARY PUBLIC My Commission Expires: ____________
This Document was prepared by: Andrew S. Hartley City Attorney 100 North Court Street Georgetown, KY 40324 502-863-9800
_________________________________
___________ Date
Exhibit A:
Stormwater Management Plan
Exhibit B:
Declaration of Covenants and Restrictions
Exhibit C:
BMP maintenance Schedules and Checklists
Exhibit D:
BMP drawings and photographs
Appendix B PLANT SELECTION Table B-1 Bioretention Species
COMMON NAME
SCIENTIFIC NAME
HEIGHT (FEET)
NOTES
GRASSES AND SEDGES Beaked Panicgrass Bluegrass Bottlebrush Grass
Panicum anceps Poa pratensis Elymus hystrix
2-3 1-2 2-3
Canada Wild Rye Drooping Sedge Fox Sedge Indian Grass Little Bluestem Orchard Grass Purpletop Redtop River Oats Switchgrass Virginia Wild Rye Woolgrass
Elymus canadensis Carex crinita Carex vulpinoidea Sorghastrum nutans Schizachyrium scoparium Dactylis glomerata Tridens flavus Agrostis alba Chasmanthium latifolia Panicum virgatum Elymus virginicus Scirpus cyperinus
2-4
Can Be Mowed Full Sun; Can be Mowed; Non-native Full Sun to Partial Shade; Dry, Well- Drained Soils; Do Not Mow Full Sun to Shade; Do Not Mow
4-6 2-4 2-3 2-3 1-3 2-4 3-7 2-4 3-5
Open Sun; Do Not Mow Full Sun; Can Be Mowed Bunchgrass; Non-native; Can Be Mowed Full Sun; Can Be Mowed Full Sun; Can Be Mowed Full Sun to Shade; Wet to Dry Soils; Do Not Mow Open Sun; Deep Rooted; Late Spring Planting Full Sun to Shade; Do Not Mow Open Sun; Wet to Dry Soils; Do Not Mow
Bee Balm Black-eyed Susan Blazing Star Blue False Indigo Blue Lobelia Bluestar Bundleflower Butterfly Milkweed Cardinal Flower
Monarda didyma Rudbeckia hirta Liastris spicata Baptisia australis Lobelia siphilitica Amsonia tabernaemontana Desmanthus illinoensis Asclepia tuberosa Lobelia cardinalis
2-4 2 1-2 3-4 3-5 1-2 2-3 2 1-3
Cream Indigo Culvers Root Downy Sunflower Dwarf Larkspur Gray Headed Coneflower Joe-Pye Weeds
Baptisia leucophae Veronicastrum virginicum Helianthus mollis Delphinium tricorne Ratibida pinnata
2-4 3-6 2-4 1 3-4
Full Sun; Attracts Butterflies; May Spread Full Sun Full Sun Full Sun; Drought Tolerant; Blue Leaf Clusters Full Sun Sun to Partial Shade Full Sun; Drought Tolerant Full Sun Sun to Partial Shade; Moist Soil; Not Drought Tolerant Full Sun; Slow Growing Full Sun to Partial Shade; Moist Soil Full Sun; Drought Tolerant Full Sun Full Sun; Drought Tolerant
Eupatorium fistulosum purpureum Asclepias incarnata
5-8
FORBS
Marsh Milkweed
2-5 B–1
Sun to Partial Shade; Moist Soil; Not Drought Tolerant Sun; Moist Soil; Not Drought Tolerant
Mist Flower Monkey Flower
Conoclinum coelestinum Mimulus ringens
2-3 1-3
New England Aster
Aster novae-angliae
2-4
Obedient Plant Orange Coneflower Prairie Dock Purple Coneflower Rattlesnake Master
Physostegia virginiana Rudbeckia fulgida Silphium terebinthenaceum Echinacea purpurea Eryngium yuccifolium
2-3 2-3 3-10 2-4 2-5
Sneezeweed Wild Bergamot Wild Blue Phlox
Helenium autumnale Monarda fistulosa Phlox divaricata
2-4 2-3 1-2
Sun to Partial Shade; Moist Soil Sun to Partial Shade; Moist Soil; Not Drought Tolerant Sun to Light Shade; Moist to Moderately Well-Drained Sun to Light Shade; Moist Soil; May Spread Full Sun; May Spread Full Sun; Slow Growing; Drought Tolerant Full Sun; Large Flower; Drought Tolerant Full Sun; Does Not Tolerate Standing Water; Unusual Appearance Full Sun; Moist Soil Full Sun; May Spread Partial to Full Shade; Not Drought Tolerant
Table B-2 Bioinfiltration Species
COMMON NAME
SCIENTIFIC NAME
HEIGHT (FEET)
NOTES
GRASSES AND SEDGES Beaked Panicgrass Bluegrass Bottlebrush Grass
Panicum anceps Poa pratensis Elymus hystrix
2-3 1-2 2-3
Canada Wild Rye Drooping Sedge Fox Sedge Indian Grass Little Bluestem Orchard Grass Purpletop Redtop River Oats Switchgrass Virginia Wild Rye Woolgrass
Elymus canadensis Carex crinita Carex vulpinoidea Sorghastrum nutans Schizachyrium scoparium Dactylis glomerata Tridens flavus Agrostis alba Chasmanthium latifolia Panicum virgatum Elymus virginicus Scirpus cyperinus
2-4
Can Be Mowed Full Sun; Can be Mowed; Non-native Full Sun to Partial Shade; Dry, Well- Drained Soils; Do Not Mow Full Sun to Shade; Do Not Mow
4-6 2-4 2-3 2-3 1-3 2-4 3-7 2-4 3-5
Open Sun; Do Not Mow Full Sun; Can Be Mowed Bunchgrass; Non-native; Can Be Mowed Full Sun; Can Be Mowed Full Sun; Can Be Mowed Full Sun to Shade; Wet to Dry Soils; Do Not Mow Open Sun; Deep Rooted; Late Spring Planting Full Sun to Shade; Do Not Mow Open Sun; Wet to Dry Soils; Do Not Mow
Monarda didyma Rudbeckia hirta Liastris spicata Baptisia australis Lobelia siphilitica
2-4 2 1-2 3-4 3-5
Full Sun; Attracts Butterflies; May Spread Full Sun Full Sun Full Sun; Drought Tolerant; Blue Leaf Clusters Full Sun
FORBS Bee Balm Black-eyed Susan Blazing Star Blue False Indigo Blue Lobelia
B–2
HEIGHT (FEET)
COMMON NAME
SCIENTIFIC NAME
Bluestar Bundleflower Butterfly Milkweed Cardinal Flower
Amsonia tabernaemontana Desmanthus illinoensis Asclepia tuberosa Lobelia cardinalis
1-2 2-3 2 1-3
Cream Indigo Culvers Root Downy Sunflower Dwarf Larkspur Gray Headed Coneflower Joe-Pye Weeds
Baptisia leucophae Veronicastrum virginicum Helianthus mollis Delphinium tricorne Ratibida pinnata
2-4 3-6 2-4 1 3-4 5-8
Marsh Milkweed Mist Flower Monkey Flower
Eupatorium fistulosum purpureum Asclepias incarnata Conoclinum coelestinum Mimulus ringens
New England Aster
Aster novae-angliae
2-4
Obedient Plant Orange Coneflower Prairie Dock Purple Coneflower Rattlesnake Master
Physostegia virginiana Rudbeckia fulgida Silphium terebinthenaceum Echinacea purpurea Eryngium yuccifolium
2-3 2-3 3-10 2-4 2-5
Sneezeweed Wild Bergamot Wild Blue Phlox
Helenium autumnale Monarda fistulosa Phlox divaricata
2-4 2-3 1-2
American Plum
Prunus americana
8-10
Azalea sp. Blackgum Blackhaw
Azalea sp. Nyssa sylvatica Viburnum prunifolium
5-8 30-80 10-15
Bladdernut Carolina Buckthorn Black and Red Chokeberry Elderberry
Staphylea trifolia Frangula caroliniana Aronia sp.
5-20 12-15 3-10
Sambucus canadensis
8-12
Ironwood Ninebark
Carpinus carolina Physocarpus opulifolius
20-30 5-8
2-5 2-3 1-3
NOTES Sun to Partial Shade Full Sun; Drought Tolerant Full Sun Sun to Partial Shade; Moist Soil; Not Drought Tolerant Full Sun; Slow Growing Full Sun to Partial Shade; Moist Soil Full Sun; Drought Tolerant Full Sun Full Sun; Drought Tolerant Sun to Partial Shade; Moist Soil; Not Drought Tolerant Sun; Moist Soil; Not Drought Tolerant Sun to Partial Shade; Moist Soil Sun to Partial Shade; Moist Soil; Not Drought Tolerant Sun to Light Shade; Moist to Moderately Well-Drained Sun to Light Shade; Moist Soil; May Spread Full Sun; May Spread Full Sun; Slow Growing; Drought Tolerant Full Sun; Large Flower; Drought Tolerant Full Sun; Does Not Tolerate Standing Water; Unusual Appearance Full Sun; Moist Soil Full Sun; May Spread Partial to Full Shade; Not Drought Tolerant
SHRUBS AND TREES
B–3
Full Sun to Partial Shade; Early White Flowers; Spreads Open to Shade; Several Kentucky Species Full Sun to Shade; Great Fall Color Full Sun to Partial Shade; Clusters of White Flowers; Fall Color Varies Partial to Full Shade; Average to Moist Soil Best in Partial Shade Full Sun to Partial Shade; Fall Color; Fruit Open to Partial Shade; Clusters of White Flowers; Black Fruit Full Sun to Shade; Moist, Acidic Soil Full Sun to Partial Shade; White Flowers
HEIGHT (FEET)
COMMON NAME
SCIENTIFIC NAME
Roughleaf Dogwood
Cornus drummondii
5-15
Rusty Blackhaw
Viburnum rifidulum
10-30
Smooth Sumac Spicebush Winged Sumac
Rhus glabra Lindera benzoin Rhus copallina
5-15 5-15 10-25
NOTES Full Sun to Partial Shade; Clusters of White Flowers; Fall Color Full Sun to Partial Shade; White Flowers and Fall Color Full Sun; Brilliant Red Fall Color; Plant in Clusters Partial to Full Shade; Red Berries Full Sun to Partial Shade
References: LFUCG Stormwater Management Low Impact Development Guidelines for New Development and Redevelopment, 2012.
Table B-3 Riparian Buffer Species
COMMON NAME
SCIENTIFIC NAME
RECOMMENDED SHADE/SUN
Chasmanthium latifolia Sorgastum nutans Panicum virgatum Agrostis alba Panicum clandestinum Andropogon virginicus Andropogon gerardii Carex Carex grayii Juncus effusus Cyperus strigosus Athyrium felix-femina Onoclea sensibilis Osmunda cinnamomea Eupatorium perfoliatum Senecio aureus Solidago rugosa Solidago gigantea Penstemon hirsutus Mimulus ringens Lobelia cardinalis Lobelia silphilitica
Shade Sun Sun Sun Shade Sun Sun Sun Shade Sun Sun Shade Shade Shade Sun Shade Sun Sun Shade Shade Shade Shade
Bigononia carpreolata Campsis radicans Decumaria barbara Arundinaria gigantea Cephalanthus occidentalis Spirea alba
Shade Sun Shade Sun Sun Sun
HERBACEOUS GROUND COVER River Oats Indian Grass Switch Grass Redtop Deertongue Broomsedge Big Blue Stem Frank’s Sedge Gray’s Sedge Soft Rush Flat Sedge Lady Fern Sensitive Fern Cinnamon Fern Common Boneset Golden Ragwort Wrinkled Goldenrod Tall Goldenrod Beard Tongue Monkey Flower Cardinal Flower Great Blue Lobelia
VINES AND SHRUBS Cross Vine Trumpet Creeper Climbing Hydrangea Giant Cane Buttonbush Meadowsweet
B–4
COMMON NAME
SCIENTIFIC NAME
RECOMMENDED SHADE/SUN
Sweetspire Spicebush Paw-paw Arrowwood Nannyberry Swamp Haw Ninebark Hazelnut Possum Haw Winterberry Chokeberry Elderberry Juneberry Mountain Camelia Sweetbells Smooth Azalea Silky Dogwood Redosier Dogwood Rough-leaf Dogwood Pagoda Dogwood Smooth Alder Sandbar Willow Silky Willow Dwarf Willow Pussy Willow Streamco Willow Bankers Willow Heart-leaf Willow
Itea virginica Lindera benzoin Asimina triloba Viburnum dentatum Viburnum lentago Viburnum nudum Physocarpus opolifolius Corylus americana Ilex decidua Ilex verticillata Aronia arbutifolia Sambucus candensis Amelanchier arborea Stewartia ovata Leucothe racemosa Rhododendron arborescens Cornus amomum Cornus stolonifera Cornus drummondii Cornus alternifolia Alnus serrulata Salix interior Salix sericea Salix humilis var. macrophylla Salix discolor Salix purpurea Salix x cotteti Salix rigida
Shade Shade Shade Shade Sun Shade Sun Sun Sun Shade Sun Sun Shade Shade Shade Shade Sun Shade Shade Shade Sun Sun Sun Sun Sun Sun Sun Sun
COMMON NAME
SCIENTIFIC NAME
HEIGHT (FT)
SPREAD (FT)
60-100 30-60 50-100 50-80 50-60 80 70 30-40 20-70 40-70 30-90 40-70 75-100
50-85 25-50 20-40 35-50 30-40 65 55 20-35 10-40 30-60 20-30 40-50 50-75
TREES Black Willow Boxelder Red Maple Silver Maple Green Ash White Ash Red Elm Silverbell Persimmon River Birch Black Gum Hackberry Cottonwood
Salix nigra Acer negundo Acer rubrum Acer saccharinum Fraxinus pennsylvanica Fraxinus americana Ulmus rubra Halesia carolina Diospryros virginiana Betula nigra Nyssa sylvatica Celtis occidentalis Populus deltoides B–5
COMMON NAME
SCIENTIFIC NAME
Sweet Gum Tulip Polar Sycamore American Beech Ironwood Yellow Buckeye Shellbark Hickory Shaqbark Hickory Pecan Black Walnut Bur Oak Pin Oak Swamp Oak Swamp Chestnut Oak
Liquidambar styraciflua Liriodendron tulipifera Plantanus occidentalis Fagus grandiflora Carpinus caroliniana Aesculus octandra Carya lacinosa Carya ovata Carya illinoensis Juglans nigra Quercus macrocarpa Quercus palustris Quercus bicolor Quercus michauxii
References: Riparian Buffers Strategies for Urban Watersheds, 1995. LFUCG Stormwater Manual, 1999.
B–6
HEIGHT (FT)
SPREAD (FT)
50-75 60-90 75-100 50-90 30 70-90 70-100 70-100 100 70-90 70-100 50-90 60-70 60-80
40-50 30-50 50-75 40-75 30 40-55 50-75 45-65 70 45-60 75-90 25-45 30-35 40-55
Appendix C BIORETENTION SOIL MIX These specifications are to be used as guidance when bioretention soil mix is called out in bioretention areas, swales, filter strips, or other vegetated BMPs. This soil mix is designed to create a soil that will drain well and has proper nutrient/organic content without leaching nutrients to underdrains, should they be used.
ADVANTAGES Rapid drainage Proper nutrient/organic content Slow release of nutrients to avoid leaching Proper pH
It is important to remember that no single bioretention soil mix will be appropriate for all circumstances. Therefore, mix design modifications may be needed depending on particulars of each use; the information below is provided as guidance. Some specific applications requiring modification include:
PHOSPHORUS REMOVAL APPLICATIONS–For situations in which high phosphorus is a problem, the P index of the soil used should be checked to ensure it is between 10 and 30. Use of a soil with a high P index can actually release phosphorus into the stormwater that passes through it. In applications where phosphorus is not an issue, a P index of 25 to 40 is appropriate (Hunt and Lord, 2006). NITROGEN REMOVAL APPLICATIONS–Nitrogen removal requires longer contact time, so soils should be mixed to reduce the hydraulic conductivity to approximately 1 inch/hour. Soil thickness should also be increased in these applications. Usually, 36 inches of soil mix is preferred. SPECIFIC HYDRAULIC CONDUCTIVITY–This is primarily affected by the percentage of fines (i.e., particles which pass a No. 200 sieve and include silt-sized and clay-sized particles) that are part of the soil mix. While there is a range of reasonable values, high permeability soils should be closer to 4% fines, while lower permeability should be closer to 12 % fines.
SPECIFICATIONS The following specifications and guidance are provided for general bioretention soil mixes with relatively high hydraulic conductivity. As mentioned above, individual BMPs may vary depending upon the specific application.
The planting media shall be highly permeable and high in organic matter (e.g., loamy sand mixed thoroughly with compost amendment) and a surface mulch layer. Planting media shall consist of 70 to 80% sand, 10 to 15% compost, and 10 to 20% clean topsoil with 98% of the media (by volume) passing through a 3/4-inch sieve (or screen). The organic content of the soil mixture should be 4 to 8%; the pH range should be 5.5 to 7.5. Sand should be free of stones, stumps, roots or other similar objects larger than 5 millimeters, and have the following gradation:
PARTICLE SIZE (ASTM D422)
% PASSING
#4 #6 #8 #50 #200
100 88-100 79-97 11-35 5-15
C–1
Compost shall be free of stones, stumps, roots or other similar objects larger than 3/4 of an inch, have a particle size of 98% passing through 3/4-inch screen or smaller and shall have dark brown color and a soil-like odor. Compost exhibiting a sour or putrid smell, containing recognizable grass or leaves, or is hot (120 F) upon delivery or rewetting is not acceptable. Compost shall also meet the following characteristics:
Topsoil shall be free of stones, stumps, roots or other similar objects larger than 2 inches, and have the following characteristics:
Soluble salts: < 4.0 mmhos/cm (dS/m) pH range: 5.5 to 7.0 Organic matter: > 4% Carbon to nitrogen ratio: < 25:1 Moisture content: 25 to 55%
PARTICLE SIZE (ASTM D422, D1140)
% PASSING
3/4" Sand (0.05 - 2.0 mm ) Silt (0.002 - 0.05 mm) Clay
98 50-75 15-40 <5
The bioretention soil shall be covered with 2 to 3 inches of mulch at the start and an annual placement of 1 to 2 inches of mulch. Intent: This will help sustain nutrient levels, suppress weeds, and maintain infiltrative capacity. Mulch shall be:
Soluble Salt Concentration: < 8 mmhos/cm (dS/m) pH: 6.0-8.0 Moisture: 30 to 60% wet weight basis Organic matter: 35 to 65% dry weight basis Physical contaminants: < 1% dry weight basis
Well-aged, shredded or chipped woody debris or plant material. Well-aged mulch is defined as mulch that has been stockpiled or stored for at least twelve months. Compost meeting the requirements above may also be used (compost is less likely to float and is a better source for organic materials). Free of weed seeds, soil, roots and other material that is not bole or branch wood and bark. A maximum of 2 to 3 inches thick. Intent: Thicker applications can inhibit proper oxygen and carbon dioxide cycling between the soil and atmosphere. Grass clippings or pure bark shall not be used as mulch.
Planting media design height shall be marked appropriately, such as a collar on the vertical riser (if installed), or with a stake inserted 2 feet into the planting media and notched to show bioretention surface level and ponding level.
C–2
The soil mix shall be tested and meet the following criteria:
ITEM
CRITERIA
Corrected pH 5.5 – 7.5 P – index 10 – 40 Hydraulic conductivity 6 – 10 in/hr Soluble salts Not to exceed 500 ppm * Use authorized soil test procedures.
TEST METHOD ASTM D4972 Mehlich 3 ASTM F1815 *
Note: Hydraulic conductivity is equivalent to permeability. Infiltration rate is equal to the hydraulic conductivity multiplied by a hydraulic gradient, which is a function of the head pressure. When submitting soil testing results, documentation should indicate if values are representative of hydraulic conductivity or infiltration rates. References: Hinman, C. Bioretention Soil Mix Review and Recommendations for Western Washington. Prepared for the Puget Sound Partnership. Washington State University. 2009. http://www.ecy.wa.gov/programs/wq/stormwater/BSMResultsGuidelines.pdf Hunt, W.F., and G.L. Lord. Urban Waterways: Bioretention Performance, Design, Construction, and Maintenance. North Carolina Cooperative Extension Service, 2006. [Online] http://www.bae.ncsu.edu/stormwater/PublicationFiles/Bioretention2006.pdf Low Impact Development Center. Bioretention Specification. [Online] http://www.lowimpactdevelopment.org/epa03/biospec.htm Virginia Department of Conservation and Recreation. Virginia DCR Stormwater Design Specification No. 9: Bioretention. 2010. (refer to Appendix 9A: Urban Bioretention).
C–3
Appendix D STORMWATER POST-CONSTRUCTION BMP INSTALLATION INSPECTION REPORT As required by Georgetown’s Post-Construction Stormwater Runoff Ordinance and outlined in Chapter 3.2.A of this Manual, the Property Owner or Responsible Entity for new development or redevelopment projects shall engage a licensed Design Professional to provide inspection services during the installation of post-construction BMPs detailed in the stormwater management plan. The Design Professional shall be responsible for reviewing and observing conformity of the work being performed by the contractor with the requirements outlined in the approved construction plans and specifications for each post construction BMP. The Planning Commission Engineer and City Engineer may also at their discretion make independent inspections as deemed necessary. These required inspections shall be performed during all phases of post-construction stormwater BMP construction to document the various components comprising the BMP once completed. See Appendix D for a copy of the installation inspection report form. Documentation for field inspection services shall include a report that references the various components that have been installed during each inspection period, in accordance with the Installation Certification Checklist. A copy of each inspection report shall be submitted to the Planning Commission Engineer by the end of the next business day following the date of each site visit. The Design Professional shall be responsible for documenting any material deviations from the approved plans and specifications that are observed during the installation of the BMP. If material deviations are observed, the Design Professional shall also immediately notify the Responsible Entity and Planning Commission Engineer of any such occurrences. This shall include a written discussion of the necessary corrective actions to be taken, if required to address the deviations. The Planning Commission Engineer and City Engineer may at their discretion require additional corrective actions as deemed necessary. In addition, the Responsible Entity shall notify the Planning Commission Engineer at least twenty-four (24) hours in advance of placing any permanent cover over stormwater infrastructure that may include storm pipe and other drainage related improvements. This notice requirement is intended to permit opportunity for inspection by the Planning Commission Engineer or City Engineer, if deemed necessary.
D–1
City of Georgetown Stormwater Post-Construction BMP Periodic Installation Inspection Report (CH 3.2.A) Applicant Name: Land Disturbance Permit Number: Project Name: Project Address:
Contractor:
Project Representative:
Inspection Date:
Representative’s Phone #:
Company:
Weather A.M.:
Weather P.M.:
List Stormwater Post-Construction Best Management Practice(s) Inspected:
BMP(s) Location on Project Site:
Installation Certification Checklist shall be completed concurrently with construction of the postconstruction BMP, including photographs documenting the construction of the post -construction BMP. (Note: Required by Ordinance No. 15-001) General Comments:
Observed variations from the approved construction plans for the post -construction BMP as listed in the Installation Certification Checklist:
Project Representative’s Signature: City of Georgetown Post-Construction BMP Installation Inspection Report October 2016
Date: Page 1
City of Georgetown Installation Certification Checklist Applicant Name: Land Disturbance Permit Number: Project Name:
BMP Type:
BMP Location on Project Site:
INSTALLATION CERTIFICATION CHECKLIST Feature Component Diameter of Underdrain
Unit
Ft/Ft
Length of Underdrain
Feet
Depth of Gravel Layer
Inches
Installation of Filter Fabric (list locations)
Yes/No
Type of Filter Fabric
Specification
Yes/No
Depth of Mulch
Inches
Plant Spacing
Spacing
Filter Bed Depth Depth of Permeable Pavement/Paver Thickness Overflow Structure Rim Elevation
Photograph ID
Date/Initials
Feet
Placement of Mulch
Type and Number of Plants
Actual
Inches
Slope of Underdrain
Depth of Bioretention Soil Mix
Required
Specification Feet Inches NAVD 88 Feet msl
City of Georgetown Post-Construction BMP Installation Inspection Report October 2016
Page 2
INSTALLATION CERTIFICATION CHECKLIST Feature Component Overflow Structure Invert Elevation Inspection of Cleanout BMP Footprint Detention/Retention Volume Storm Pipe/ Culverts/ Ditches Provide Positive Flow and Free of Debris and Sediment Deposits
Unit
Required
Actual
Photograph ID
Date/Initials
NAVD 88 Feet msl Yes/No Square Feet Cubic Feet Yes/No
Other:______________
Other:______________
Other:______________
Note: Design Professional shall tailor the Certification Checklist to the selected post-construction stormwater BMP(s) for the new development or redevelopment project and include key performance feature components from Chapter 5 (Stormwater BMP Fact Sheets). Additional Comments:
Engineer’s Signature:
City of Georgetown Post-Construction BMP Installation Inspection Report October 2016
Completion Date:
Page 3
Appendix E POST-CONSTRUCTION BMP INSTALLATION CERTIFICATION As required by the City of Georgetown’s Post-Construction Stormwater Runoff Ordinance and outlined in Chapter 3.2.B of this Manual, the licensed Deign Professional shall submit the Final Inspection Report and Installation Certification upon completion of construction for the post-construction stormwater BMP(s). The certification shall include as-built drawings, photographs of the installed BMP, and other required documentation as detailed in the installation certification.
E–1
City of Georgetown Post-Construction BMP Installation Certification (CH 3.2.B) Applicant Name: Land Disturbance Permit Number: Project Name: Project Address: Stormwater Post-Construction Best Management Practice(s) Installed:
Note: This certification statement must be executed by the licensed Design Professional responsible for providing resident observation services during construction of the post -construction BMP. Periodic construction observation by the certifying Design Professional in responsible charge or his/her designee will be required to fulfill this certification. The certifying person must supply the Planning Commission Engineer with the complete Installation Certification Checklist, as -built drawings and other required documentation to fulfill expectations with this requirem ent. Any deviations reflected in the as-built drawings shall be reviewed by the Design Professional in relation to the approved design and determined not to materially affect the intended performance of the post-construction BMP. LICENSED DESIGN PROFESSIONAL CERTIFICATION STATEMENT To the best of my knowledge and belief, I hereby certify that the post-construction stormwater management BMP(s) identified herein have been constructed in accordance with the approved construction drawings, design documents, specifications, and/or any approved modifications, on file with the Planning Commission Engineer except as otherwise noted on the as-built drawings. Included with this certification statement is all necessary supporting documentation as outlined on Page 2 of this document. Licensed Design Professional: Signature: Printed Name:
Date:
Contact Information: City of Georgetown Post-Construction BMP Installation Certification October 2016
Page 1
The following supporting documents are included with the hard copy and the PDF electronic file of this Post-Construction BMP Installation Certification: Copy of the as-built drawings for the facility (PDF). Copy of the revised materials summary sheet for the facility based on as-built conditions (PDF). This should include copies of material delivery tickets (see Installation Certification Checklist for required materials). An original completed copy of the Installation Certification Checklist required by the Planning Commission Engineer for each constructed BMP (PDF). Color digital photographs of the required installation components (per the Installation Certification Checklist) and the completed facility. A letter from the Contractor certifying the installation of the specific plants required at the facility is in accordance with approved plant material, if applicable (PDF). Documentation by the supplier of the amended soil that the biofiltration soils mix meets the required specifications, if applicable (Original Hard Copy and PDF). Additional Items Included:
Additional Comments:
City of Georgetown Post-Construction BMP Installation Certification October 2016
Page 2
City of Georgetown Installation Certification Checklist Applicant Name: Land Disturbance Permit Number: Project Name:
BMP Type:
BMP Location on Project Site:
INSTALLATION CERTIFICATION CHECKLIST Feature Component Diameter of Underdrain
Unit
Ft/Ft
Length of Underdrain
Feet
Depth of Gravel Layer
Inches
Installation of Filter Fabric (list locations)
Yes/No
Type of Filter Fabric
Specification
Yes/No
Depth of Mulch
Inches
Plant Spacing
Spacing
Filter Bed Depth Depth of Permeable Pavement/Paver Thickness Overflow Structure Rim Elevation
Photograph ID
Date/Initials
Feet
Placement of Mulch
Type and Number of Plants
Actual
Inches
Slope of Underdrain
Depth of Bioretention Soil Mix
Required
Specification Feet Inches NAVD 88 Feet msl
City of Georgetown Post-Construction BMP Installation Certification October 2016
Page 3
INSTALLATION CERTIFICATION CHECKLIST Feature Component Overflow Structure Invert Elevation Inspection of Cleanout BMP Footprint Detention/Retention Volume Storm Pipe/ Culverts/ Ditches Provide Positive Flow and Free of Debris and Sediment Deposits
Unit
Required
Actual
Photograph ID
Date/Initials
NAVD 88 Feet msl Yes/No Square Feet Cubic Feet Yes/No
Other:______________
Other:______________
Other:______________
Note: Design Professional shall tailor the Certification Checklist to the selected post-construction stormwater BMP(s) for the new development or redevelopment project and include key performance feature components from Chapter 5 (Stormwater BMP Fact Sheets). Additional Comments:
Engineer’s Signature:
City of Georgetown Post-Construction BMP Installation Certification October 2016
Completion Date:
Page 4
Appendix F STORMWATER MANAGEMENT PLAN SUBMITTAL CHECKLIST As outlined in Chapter 3.2.A of this Manual, a Stormwater Management Plan must be submitted by the applicant for approval by the Planning Commission Engineer. Submittals shall include the Stormwater Management Plan Submittal Checklist. The purpose of the checklist is to facilitate the review process and provide minimum requirements for the Stormwater Management Plan submittal.
F–1
Stormwater Management Plan Submittal Checklist (CH 3.2.A) Project Name: ____________________________________________________________________________________ Project Address: _____________________________________
Parcel No.:__________________________________
Applicant Name: _____________________________________
Date: ______________________________________
Applicant Address: ________________________________________________________________________________ Applicant Phone No.: __________________________________
Email Address: ______________________________
Licensed Design Professional (LDP) Name: _____________________________________________________________ LDP Phone No: _______________________________________
Email Address: ______________________________
Stormwater Management Plan Requirements A Stormwater Management Plan must be submitted by the applicant for approval (paper and PDF submittal). The applicant shall be the property owner or his or her designee, such as the developer (Responsible Entity). All stormwater management plans are to be reviewed and approved by the Planning Commission Engineer. The purpose of this checklist is to facilitate the review process. This checklist gives the minimum requirements needed for the Planning Commission’s review based on Chapter 3 of the Georgetown Stormwater BMP Manual. All items shall be checked as included or marked N/A with an explanation. Omission of required items may cause for rejection of the submittal without review. Topographic Base Map
See Section 3.1.A Construction Plans for a description of requirements. Stormwater Management Facilities
The stormwater management plan shall clearly delineate all detention basins, pipes, inlets, culverts, channels, etc. required to meet the stormwater management design criteria in Chapter 4 of this Manual. This shall also include proposed post-construction stormwater BMPs. Post-Construction Stormwater BMP(s)
Approved water quality related practices as detailed in Chapter 5 of this Manual shall be used in developing stormwater management plans, where required, to satisfy the water quality design criteria. Refer to Section 4.3 for water quality design criteria applicable to new development and redevelopment projects. Design Documents
The stormwater management plan shall include construction plans and specifications showing all details necessary to construct the proposed improvements, including a drainage report with all engineering calculations to comply with design requirements for each element of the stormwater system of improvements. See Section 3.1.A Construction Plans and Section 3.1.B Drainage Reports. Calculations and Soil Information
See Section 3.1.B Drainage Reports for a description of requirements. City of Georgetown Stormwater Management Plan Submittal Checklist October 2016
Page 1
Erosion and Sediment Control Plans for Construction
The applicant must prepare a SWPPP, Erosion Prevention and Sediment Control (EPSC) Plan, and Grading Plan as applicable to the project, in accordance with the City’s Erosion and Sediment Control Ordinance No. 2010-014. Landscaping Plan
If the construction drawings include the installation of a post-construction stormwater BMP(s) requiring vegetation and plant material, the landscaping plan shall be included as an attachment to the Post-Construction Stormwater BMP Operations and Maintenance Agreement. Drainage Easements
The applicant must ensure suitable access to all stormwater facilities (i.e., right-of-entry granted by the property owner to the City) for the purpose of ongoing inspection, maintenance, and repair. Right-of-entry shall be in legal form with easements sufficient for this purpose by deed or record plat. Stormwater BMP Construction Cost Estimate
The applicant shall provide an itemized estimate of probable cost prepared by the Design Professional for the proposed post-construction stormwater BMP(s). Other Environmental Permits
The applicant shall ensure that all other applicable regulatory permits have been acquired for the project prior to approval of the final Stormwater Management Plan. Copies of all applicable permits obtained shall be submitted with the stormwater management plan. The following Items to be submitted upon competition of construction prior to issuance of the Certificate of Occupancy and/or approval of the final record plat: Stormwater Management/BMP Facilities Operations and Maintenance Agreement
The applicant must execute an operations and maintenance agreement binding on all subsequent owners of land served by Stormwater Management/BMP facilities in accordance with the requirements of this BMP Manual. Applicable inspection schedules and maintenance checklists, including any manufacturer-provided schedules shall be incorporated with the Agreement. See Appendix A for the operations and maintenance agreement template. Record Drawings
Record drawings for all storm drainage-related infrastructure shall be submitted upon completion of construction to document the actual construction and reflect all changes made in the specifications and construction drawings during the construction process. See Section 3.1.A.3 Record Drawings. “As-Built” Drawings
Upon final completion of a required post-construction stormwater BMP, the applicant shall submit stamped and signed “as-built” drawings accompanied with a completion certification by a licensed design professional (Design Professional). See Section 3.2.B Stormwater Facility Completion Certification. Comments for the Reviewer:
City of Georgetown Stormwater Management Plan Submittal Checklist October 2016
Page 2
