Balancing Airport Stormwater and Bird Hazard Management (2015)

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35 A P P E N D I X E Local and State Stormwater Criteria Summary Matrix

Source Information Development Information Water Quantity Control Municipality or State FAA Region1 Regulating Entity Documents Reviewed stimiL wolF kaePtnempoleveD-erP fo noitinifeDytilibacilppA tnempoleveD)stimreP ,slaunaM( Stream Protection Volume or Other Minimum noitartlifnI / lortnoC emuloV ffonuRstnemeriuqeR egarotS LOCAL Columbus, OH Great Lakes City of Columbus Division of Sewerage and Drainage (DOSD) Stormwater Drainage Manual (Aug 2012) New and redevelopment, >10,000 SF disturbance or >2,000 SF added impervious Existing Conditions (no detailed definition is available). Restrict the 100-year post peak flow to the 10-year pre-peak flow. Restrict the Critical Storm (storm event determined based on increase in 1-year storm runoff) post peak flow to the 1-year pre- peak flow. None None Portland, OR Northwest Mountain City of Portland Bureau of Environmental Services (BES) Stormwater Management Manual (2008) Sewer and Drainage Facilities Design Manual (2011) New or redevelopment > 500 SF of impervious surface. Existing development proposing new offsite discharges. Undeveloped Land Use "Lewis and Clark Era." Depends on where runoff is discharged. -Base Condition: Maintain peak flow rates at pre-development levels for the 2-year, 5-year, and 10-year, 24-hour events. -Combined Sewer: Limit the 25-year post-development peak runoff rate to the 10-year pre-development peak rate. -Columbia River, Willamette River, or Columbia Slough: None -All other drainage systems: 2-year post to one-half of the 2-year pre; 25-year, 10-year, 5-year post to corresponding pre. None Infiltrate to the maximum extent feasible. (1-9). Dallas, TX Southwest City of Dallas, North Central Texas Council of Governments Integrated Stormwater Management (iSWM) Criteria Manual (2010) Site Development Controls Technical Manual (2010) Land disturbing activity of 1 acre or more OR land disturbing activity of less than 1 acre where the activity is part of a common plan of development that is one acre or larger. Development and redevelopment are not specifically defined in this manual. If clearing and grubbing has been performed in the past 5 years, than assume clearing and grubbing has not occurred. Common practice requires the designer to control peak flow at the outlet of a site such that the post-development peak discharge equals the pre-development peak discharge. Provide on-site controlled release of the 1-year, 24- hour storm event over a period of 24 hours (Streambank Protection Volume, SPV) (ALTERNATIVES INCLUDE DOWNSTREAM STABILIZATION AND SW CONTROLS TO IMPROVE EXISTING DS CONDITIONS). Storm Drain Design (pipes and culverts) 100-yr, 24-hour: Provide adequate controls onsite or downstream to maintain existing downstream conditions. Roanoke, VA Eastern City of Roanoke, Department of Planning Building and Development Stormwater Management Design Manual (2007) Generally applicable to land development projects that disturb more than 5,000 SF. Site conditions that have existed for the 5-year period before the site plan application and shall use the site condition that results in the lowest peak rate of runoff. 10 year post shall not exceed 10 year pre 2 year post shall not exceed 2 year pre None None Memphis, TN Southern City of Memphis Division of Public Works and Division of Engineering Shelby County Public Works Department Storm Water Management Manual (Volumes 1, 2, and 3) (2007) All development and land disturbance activities one acre or greater shall be in compliance with capital improvement projects. Pre-Development Conditions (no detailed definition is available). 25 year post shall not exceed 25 year pre 10 year post shall not exceed 10 year pre Attenuate the post- development outflow from hour 11 to hour 18 of the 24-hour storm to a level not to exceed the pre-development mass outflow for the same time period for both the 2-year and 5-year, 24- hour storms. The facility may be designed to infiltrate runoff to groundwater rather than transmit it downstream under conditions up to a 10-year, 24-hour storm event. STATE Rhode Island New England Rhode Island Department of Environmental Management (RIDEM) Stormwater Design and Installation Standards Manual (2010) Development: The construction of new impervious areas on undeveloped land is subject to the requirements of this manual even if other portions of the site are currently developed, unless the site meets the definition for an infill project. Re-Development: Any construction, alteration, or improvement that disturbs a total of 10,000 square feet or more of existing impervious area where the existing land use is commercial, industrial, institutional, governmental, recreational, or multifamily residential. The standard for characterizing pre-development land use for on-site areas shall be woods, meadow, or rangeland. For agricultural land, use a CN representing rangeland. Control the post-development peak discharge rates from the 10- year and 100-year storms to the corresponding predevelopment peak discharge rates. Calculations must be provided that show how runoff from the 10- and 100-year storms reaches the proposed facilities. Channel Protection Volume (CPv) = 24-hour extended detention of the volume of the post-development 1- year, 24-hour Type III storm event Maintain pre-development annual groundwater recharge volume to the maximum extent practicable through the use of infiltration measures Rev = (1”)(F)(I)/12 Rev = groundwater recharge volume (ac-ft) F = recharge factor, see Table 3-4 I = Impervious area (acres) Pennsylvania Eastern Pennsylvania Department of Environmental Protection (PADEP) Pennsylvania Stormwater Best Management Practices Manual (2006) For regulated activities less than or equal to 1 acre VOLUME CONTROL GUIDELINE 1 or VOLUME CONTROL GUIDELINE 2 may be used. For regulated activities greater than 1 acre, VOLUME CONTROL GUIDELINE 2 may be used. Existing non-forested pervious areas must be considered meadow (good condition) or equivalent. Twenty percent of existing impervious area shall be considered meadow (good condition) for existing conditions or redevelopment. Do not increase the peak rate of discharge for the 1-year through 100-year events (at minimum); as necessary, provide additional peak rate control as required. VOLUME CONTROL GUIDELINE 1: Do not increase the post-development total runoff volume for all storms equal to or less than the 2- year/24-hour event. CONTROL GUIDELINE 2: If VOLUME CONTROL GUIDELINE 1 is not followed, and project does not require design of SW storage facilities. 1.) Stormwater facilities shall be sized to capture at least the first two inches (2”) of runoff from all contributing impervious surfaces. 2.) At least the first one inch (1.0”) of runoff from new impervious surfaces shall be permanently removed from the runoff flow. Removal options include reuse, evaporation, transpiration, and infiltration. 3.)Wherever possible, infiltration facilities should be designed to accommodate infiltration of the entire permanently removed runoff; however, in all cases at least the first one-half inch (0.5”) of the permanently removed runoff should be infiltrated. Minnesota Great Lakes Minnesota Pollution Control Agency (PCA) Minnesota Stormwater Manual (2005). Construction General Permit (2008). Projects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger Common Plan of Development or Sale. The Minnesota Pollution Control Agency (MPCA) uses land cover conditions immediately preceding the current development project as the Minnesota Construction General Permit (CGP) pre- development condition. None. Extended detention for WQv of 24-48 hours to minimize stream bed erosion from frequent small storms. None required, although recharge and infiltration are strongly encouraged through better site design and stormwater credits. Washington Northwest Mountain Washington State Department of Ecology Water Quality Program Stormwater Management Manual for Western Washington (2012) Western Washington Phase II Municipal Stormwater Permit (2010) Land development projects that disturb greater than 2,000 square feet, or greater, of new, replaced or new plus replaced impervious surface area, or has a land disturbing activity of 7,000 square feet or greater. Additional requirements exist for 5,000SF, or more of new impervious surface area, 3/4 acre or more of native vegetation to landscape, or converts 2.5 acres of native vegetation to pasture. Forested or Plains Stormwater discharges shall match developed discharge durations to pre-developed durations for the range of pre- developed discharge rates from 50% of the 2-year peak flow up to the full 50-year peak flow. Infiltrate, disperse, and retain stormwater runoff onsite to the maximum extent feasible Infiltrate, disperse, and retain stormwater runoff onsite to the maximum extent feasible. Florida (Southwestern Water Management District)2 Southern Southwest Florida Water Management District Southwest Florida Water Management District: Environmental Resource Permit Applicant's Handbook Volume II - Design Requirements for Stormwater Treatment and Management Systems Water Quality and Water Quantity (2013)3 SW District complies with state requirement. State environmental resource permits and corresponding stormwater treatment are needed for all new or modified stormwater discharges and for all projects disturbing 4,000 square feet or more of impervious surface. The NPDES stormwater generic permit is required for all sites that disturb one or more acres of land. Sites that discharge to Open Water Sources (OWS) are not required to meet water quantity discharges but are required to meet water quality criteria. Existing Land Use Condition The post-development peak discharge rate will not exceed the pre-development peak discharge rate for a specific design storm. The design storm for the SWWMD is a 25 year, 24 hour design storm. No requirement for discharges to tidal water bodies. For projects discharging within a closed drainage basin: The total post development volume leaving the site shall be no more than the total pre-development volume leaving the site for the design 100-year storm. The rate of runoff leaving the site shall not cause adverse off-site impacts. Where practicable, systems shall be designed to maintain water tables, base flows and low flows at the highest practicable level. Footnotes: 2 The Department of Environmental Protection is involved in managing the quality and quantity of water through its relationship with the state's five water management districts. 3The Southwest Florida Water Management District (SWFWMD) Stormwater Management Manual is under review for approval by the SWFWMD. The information provided here reflects the current draft format. 1Alaskan = AK; Central = IA, KS, MO, NE; Eastern = DC, DE, MD, NJ, NY, PA, VA, WV; Great Lakes = IL, IN, MI, MN, ND, OH, SD, WI; New England = CT, ME, MA, NH, RI, VT; Northwest Mountain = CO, ID, MT, OR, UT, WA, WY; Southern = AL, FL, GA, KY, MS, NC, PR, SC, TN, VI; Southwest = AR, LA, NM, OK, TX; Western-Pacific = AZ, CA, HI, NV, GU, AS, MH

Municipality or State LOCAL Columbus, OH Portland, OR Dallas, TX Roanoke, VA Memphis, TN STATE Rhode Island Pennsylvania Minnesota Washington Florida (Southwestern Water Management District)2 Water Quality Control BMP Requirements Pertinent to Hazardous Wildlife Risk Water Quality Treatment Volume or Flow Capture and Treat Requirements Special Requirements for Habitat / Sensitive emiT nwodwarDsepolsediSnoitategeVlooP tnenamrePsnoitaredisnoC LDMT laicepSWatershed Airport Considerations/Limitations on the Selection of BMPs/Controls Design Quality BMPs to treat minimum Water Quality enoNenoN)emulov ffonur llafniar hcni-57.0( wolF ro emuloV ytilauq retaw rof deriuqeRenoN Required for stabilization and water quality features. Native and tolerant species recommended 4:1 or flatter 24-48-hour minimum, depending on BMP (min. 48 for dry basins) List of acceptable controls provided, can use alternative BMPs if demonstrate benefits. SBUH 0.83-inch 24-hour NRCS Type 1A. Size BMP for capturing 90% volume and removing 70% TSS. None BMP must be capable of reducing the pollutant of concern, as approved by BES. Required for water quality Required to the maximum extent feasible. Minimize need for herbicides and mowing. Appropriate for soil and hydrologic conditions. 3:1 or flatter Drawdown times only mentioned for 2 BMPs. 10-hr for soakage trench. <10min for Drywell Vegetated BMPs required. Where vegetated BMPs are not feasible, manufactured BMPs may be approved by BES. Rooftops with UIC and Temporary SW Controls are exempt. A list of select BMPs and design criteria are provided. Treat the Water Quality Protection Volume by reducing total suspended solids from the development site for runoff resulting from rainfall of 1.5 inches (85th percentile storm). (ALTERNATIVES FOR MEETING THE WQv INCLUDE OFFSITE MITIGATION AND APPROVED ONSITE MITIGATION PRACTICES) WQ controls not specified in the manual may be used provided they can demonstrate removal of 70% to 80% of the annual average TSS. None Ability to provide bacteria removal may be of particular concern when meeting regulatory water quality criteria under the Total Maximum Daily Load (TMDL) program. Required for water quality Required in vegetative stabilization and some water quality features. Specified recommended tolerances are based on BMP application. 3:1 or flatter Only required for Porous Paver Systems & Porous Concrete: 24- 48 hours. List of acceptable controls provided, can use alternative BMPs if benefits can be demonstrated. WQv design criteria is defined per BMP. The WQV is equal to the volume from the first ½ inch of stormwater runoff from all the impervious surfaces passing through the BMP. BMP selection is based on a calculation of the total phosphorus that must be removed to provide post- development runoff pollutant levels that do not exceed pre- development runoff levels. The accepted calculation procedure for the determining the pre- and post-developed pollutant loads is the Simple Method. ytilauq retaw rof deriuqeRenoNenoN Required in vegetative stabilization and some BMPs (erosion resistant) . Specified vegetation maintenance is based on BMP application. 3:1 or flatter All stormwater detention facilities shall be empty within 72 hours following the storm event. List of acceptable controls provided, can use alternative BMPs if benefits can be demonstrated. None identified. The overall GOAL of WQ treatment is to capture 90% of annual SW runoff volume, using a design storm of 1.0 inch rainfall. None Only as it applies to animal waste and fecal coliform in Sanitary Sewer Overflows. In place of a permanent pool, a wet detention basin can be enhanced with other storm water treatment BMPs such as a pretreatment sediment forebay, baffle box, or storm water quality inlet. Preservation of existing vegetation in some circumstances. Required in vegetative stabilization and some BMPs. Vegetation is based on BMP application. 4:1 or flatter Detention storage volume necessary to meet SWMM requirements shall be drained in 72 hours. Underground detention is prohibited and open water surface vegetated BMPs encouraged for water quality. WQv (ac-ft) = (Impervious Area in acres)/12 = I/12 WQf (cfs) = unit peak discharge (cfs/mi2/inch) * Drainage Area (acres) * WQv / A Structural BMPs are generally required to achieve the following minimum average pollutant removal efficiencies: 85% removal of total suspended solids (TSS), 60% removal of pathogens, 30% removal of total phosphorus (TP) for discharges to freshwater systems, and 30% removal of total nitrogen (TN) for discharges to saltwater or tidal systems Stormwater discharges from land uses with higher potential pollutant loads (LUHPPLs) require the use of specific source control and pollution prevention measures and the specific stormwater BMPs approved for such use. On a case-by-case basis, applicants may be required to calculate potential stormwater pollutant loadings for projects for pre-development and post- development conditions. Using the Simple Method. Required for water quality. Required in vegetative stabilization and some water quality features. Specified tolerances and planting recommendations based on BMP application. Native plants are encouraged. 3:1 or flatter Drawdowns only mentioned for two BMPs. Filtering systems should be cleaned if drawdown exceeds 36 hours. Infiltration practices have a maximum dewatering time of 48 hours. Wet Ponds are not listed as a BMP option. Instead, Wet Vegetated Treatment Systems (WVTS) are listed. WVTS require a permanent pool and vegetation for WQ treatment. The WQv must be treated by one of the BMPs listed in the manual. However, a method for adding innovative and emerging BMPs to the manual is provided. WQv = 2year 24 hour event. The recommended control guideline for total water quality control is: Achieve an 85% reduction in post-development particulate associated pollutant load (as represented by Total Suspended Solids), an 85 percent reduction in post- development total phosphorus loads, and a 50 percent reduction in post-development solute loads (as represented by NO3-N), all based on post-development land use. VOLUME CONTROL GUIDELINES may require modification, on a case-by-case basis, before they are applied to Special Management Areas around the Commonwealth. In Areas Tributary to High Quality and Exceptional Value (Special Protection) Waters—there shall be no degradation of existing or designated stream quality through a change in post construction stormwater runoff volume, rate and quality Required for water quality. BMP Plant list with Plant type, Hardiness, Availability, Wildlife Value, Wetland Indicator Status, Inundation Tolerance. 3:1 or flatter Retention and detention facilities should be designed to completely drain water quality volumes including both the permanently removed volume and the extended detention volume over a period of time not less than 24 hours and not more than 72 hours from the end of the design storm. A series of flow charts and worksheets walks the designer through non-structural BMPs, VOLUME CONTROL GUIDELINES 1 & 2, and ultimately through WQ calculations and structural BMPs to determine if WQ requirements are met. WQv = 1/2 inch of runoff from the new impervious surfaces created. Reduce at least 80% of the average annual total suspended solids (TSS) load and floatable debris, including oil and petroleum products (Assumed to be achieved by water quality volume control standards alone or in combination with pretreatment). Multiple and Various. Generally the Stormwater Manual Tables 10.2 and 10.4 defines the design criteria for Special Waters and other Sensitive Receiving Waters. The local authority may adopt a "no net increase" The selection and design of specific BMPs to address impaired water pollutant reductions will be determined through the TMDL process. Required by the Construction General Permit. Required in vegetative stabilization and some water quality features. Specified tolerances recommended based climate and mitigating mosquito habitats. 3:1 or flatter The REQUIRED drawdown time for bioretention practices is 48 hours or less from the peak water level in the practice List of acceptable controls provided, can use alternative BMPs if demonstrate benefits. WQv = 6 mo., 24-hour event The requirement to provide phosphorous control is determined by the local government with jurisdiction (e.g., through a lake management plan), or the Department of Ecology (e.g., through a waste load allocation). Enhanced treatment for reduction in dissolved metals is required for the following project sites that discharge to fish-bearing streams, lakes, or to waters or conveyance systems tributary to fish-bearing streams or lakes: Industrial project sites, Commercial project sites, multi-family project sites, and high AADT roads. Specific TMDL requirements exist per identified TMDL. See Western Washington Phase II Municipal Stormwater Permit, Appendix II Required for water quality. Preservation of existing vegetation in some circumstances. Required in vegetative stabilization and some BMPs. Specific vegetation is based on BMP application. 3:1 or flatter Infiltration basin/trenches have a maximum drawdown time of 48 hours. Sand filters should drawdown in less than 24 hours. List of acceptable controls provided, can use alternative BMPs if demonstrate benefits. Drainage Areas Greater than 100 acres and all wet Detention Systems WQv = 1inch of runoff Drainage Areas Less than 100 acres WQv = 0.5 inch runoff. (STATE REQUIREMENT) New stormwater discharges must achieve at least 80% reduction of the average annual load of pollutants that would cause or contribute to violations of State water quality standards. However, current rules are based on TSS load reduction. New rule under development is based on TN and TP reduction. Projects discharging directly into Outstanding Florida Waters (OFW) shall be required to provide treatment for a volume 50% more than required for the selected treatment system New stormwater discharges to impaired waters must achieve “net environmental improvement” which means that the loading from the site for the pollutant of concern must not increase above current levels. Required for water quality. Planting is not required although vegetation that becomes established requires maintenance. 4:1 or flatter Total treatment volume shall be available within 72 hours. Only volume available within 36 hours is considered water quantity storage. A series of BMP manuals, provided in the appendices, specify BMP's by land use. The Florida Airport Best Management Practices Manual is proposed as an appendix to the SWFWMD manual, and is awaiting approval.