Green Stormwater Infrastructure - Volume 2: Guidebook (2017)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

24 This section will prompt airport practitioners to assess drainage issues as well as known and potential sources of polluted runoff at their airport. This assessment will help to clarify which areas may or may not be suitable for GSI and to identify BMP design features that may need to be con- sidered in planning for GSI. For example, some areas prone to spills may be inappropriate for GSI. Regional and Local Considerations Existing Concerns in Local Receiving Waters Airport practitioners may wish to review existing water quality constituents of concern in their local watershed [e.g., total suspended solids (TSS), heavy metals, nutrients, herbicides and fertilizers, biological oxygen demand, chemical oxygen demand, total dissolved solids]. As noted previously, these issues can be identified by consulting the airport NPDES permits as well as lists of impaired waters and total maximum daily loads (TMDLs.) Constituents of concern may vary among airports depending upon local or regional water quality concerns. For example, Seattle–Tacoma International Airport focuses on the control of copper and zinc to comply with efforts to reduce toxicity to salmonids in Puget Sound (Wash- ington State Department of Ecology 2011). In Naples, Florida, airport staff have indicated that nutrients are an important concern in runoff because of the Statewide Unified Stormwater Rule. Climate Considerations The frequency, intensity, and total precipitation of typical rainfall events will need to be consid- ered in planning for BMPs. The specific design storm for GSI is generally provided by local regula- tory requirements. The typical design storm for GSI is generally based on a storm event generating 1 inch or less of rainfall. These climate considerations will be incorporated by the stormwater engineers into BMP design if the airport should move forward with implementing GSI. Although most BMP types can be used in a variety of climate settings, there may be some climate constraints for GSI BMP selection. For example, green roofs may not be appropriate for hot or dry climates. Airport-Specific Information The specific operations and land use at an airport will influence the types and loadings of pollutants generated at the airport. These factors may include the overall volume of air traffic, whether the airport includes a tank farm and fuel hydrants, the percentage of impervious area, and the number and types of commercial tenants at the airport. Under Section 303(d) of the Clean Water Act, states, terri- tories, and authorized tribes are required to submit lists of waters that are impaired (i.e., too polluted or other- wise degraded to meet water quality standards). States are required to establish priority rankings for waters on the lists and develop TMDLs for these waters. Lists of impaired waters and TMDLs are reviewed in U.S. EPA’s regional offices and can be found on the U.S. EPA web- site (https://www.epa.gov/ TMDL/impaired-waters-and- tmdls-identifying-and-listing- impaired-waters), where Section 305(b) Water Assess- ments can also be found. Reviewing such information, in conjunction with site per- mit conditions, may be useful to airports in planning for the pollutant removal needs of their stormwater manage- ment programs. S t e p 3 Screening GSI Best Management Practices

Screening GSI Best Management practices 25 The scale and type of operations at smaller GA airports, for example, often vary substan- tially from those at large commercial airports. Operations at GA airports would include activities such as self-service aircraft fueling (by pilots), which would not normally occur at large commercial airports. In addition, the proportion of non-airport activities at a GA air- port may vary substantially from large airports. GA airports may not have the same quantity and type of ground service equipment (tow tractors and other equipment) that commercial airports might have. An example of how the differences in the scale of activity between a large commercial airport and a GA airport affect stormwater pollutant loadings can be seen in the Maryland Airport Administration (MAA) system. At Baltimore/ Washington International Thurgood Marshall Airport (BWI), fueling of aircraft and ground service equipment requires 850,000 gallons of fuel per day. In contrast, 3,500 gallons per day of fuel are required for aircraft fueling at the GA airport, Martin State Airport (Maryland DOT MAA, n.d.). Due to the much greater fueling and frequency of fuel transfer activity (via loading/unloading) at BWI, the amount of potential pollutants from fuel (including total petroleum hydrocarbon, oil and grease) may be increased proportionally. Deicing activities may also differ between GA and larger commercial airports. For GA air- ports, deicing activities are quite limited in comparison with commercial airports. For example, within the MAA system, minimal deicing occurs at the GA airport Martin State in comparison to BWI because GA aircraft rarely fly during winter storms (Maryland DOT MAA, n.d.). Although water contaminated with deicing fluid is normally collected and treated, residue remains in the stormwater runoff from most airports. Airport practitioners will likely want to evaluate both facility-specific information and records as well as information in the primer. Examples of potential sources of facility-specific data and information include the following: • The airport’s stormwater pollution prevention plan. • Known locations of any drainage issues that are not under control or where an alternative stormwater management strategy is desired. • Data on site hydrology including runoff volumes from the facility. • Any data on water quality of facility runoff, such as permit-required monthly/quarterly/ annual stormwater sampling and analysis. The following subsections summarize the pollutant loading from stormwater runoff at both the airside and landside portions of airports. These example loadings from each activity at an airport will serve as a reference for airport practitioners when planning stormwater management strategies. Airside Land Uses Airside land uses include taxiways and runways as well as those areas where significant activi- ties occur related to aircraft maintenance, fueling, or preparation for boarding. These areas include aprons, hangars, fueling areas, and deicing and anti-icing areas. There may also be areas where there is ongoing construction. Because of the lower number of activities on taxiways and runways (except at specific locations such as where touchdowns occur), pollutant loadings are expected to be lower than in the areas with maintenance and fueling activities. At some air- ports (e.g., Seattle–Tacoma International Airport) runoff is directed from aprons, hangers, and

26 Green Stormwater Infrastructure fueling areas into the industrial wastewater collection system rather than the separate collection system for runoff from other activities. Table 4 summarizes typical activities and pollutants associated with airside land uses and potential effects of those pollutants on runoff water quality. It also provides some examples of contaminant concentrations in airport runoff as reported in the literature; users should be aware that concentrations in runoff will vary widely due to a number of variables including the specific practices and levels of activity (numbers of vehicles and flights) at the airport, storm size and intensity, and antecedent conditions (number of dry days). Additional Information on Deicing/Anti-icing Deicing and anti-icing chemicals for aircraft include either propylene glycol or ethylene gly- col. Products for pavement may also include urea, potassium acetate, sodium acetate, sodium formate, and potassium formate. Problems associated with incorporation of these chemicals into runoff can include increased BOD5, growth of nuisance bacteria, ammonia toxicity to aquatic organisms (if urea is used), or foaming at stormwater outfalls (Mericas et al. 2009). Runoff from deicing operations is regulated pursuant to federal and state industrial stormwater permitting programs. Furthermore, U.S. EPA has developed airport deicing effluent limitation guidelines. These requirements, promulgated in 2012, have been incorporated into NPDES permits (40 CFR Parts 9 and 449). Although deicing and anti-icing chemicals may be incorporated into runoff, GSI is not a primary treatment strategy for airport deicing operations. Some airports (e.g., Akron-Canton Airport, Albany International Airport, and Bradley International Airport) have built specialized systems to capture and treat runoff containing deicing chemicals. Other airports collect the deicing wastewater and direct it to local municipal wastewater treatment plants. Some airports discharge wastewater containing residual propylene glycol and ethylene glycol directly to receiv- ing waters within the compliance requirements of their NPDES permits. References and Other Information Sources • Shi, X. 2008. ACRP Synthesis of Airport Practice 6: Impact of Airport Pavement Deicing Products on Aircraft and Airfield Infrastructure. Transportation Research Board of the National Academies, Washington, D.C. • AC 150/5300-14B, Design of Aircraft Deicing Facilities. • AC 150/5220-18A, Buildings for Storage and Maintenance of Airport Snow and Ice Control Equipment and Materials. • AC 150/5200-30B, Airport Winter Safety and Operations. • AC 120-60B, Ground Deicing and Anti-icing Program. Additional Information on Construction Activities Problems with runoff from construction activities can occur on either the airside or landside of the airport. A primary effect on runoff quality associated with construction projects is sedi- ment export. The sediment generated from construction sites can be 10 to 20 times greater than agricultural lands and 1,000 to 2,000 times greater than forested lands (U.S. EPA 2005). The silt and other pollutants from construction sites can cause physical, chemical, and biological harm to receiving waters. The 2000 National Water Quality Inventory indicates that sediment is one of the most widespread pollutants affecting assessed rivers and streams, second only to pathogens (bacteria) (U.S. EPA 2002). Stormwater BMPs that manage stormwater from construction activi- ties are designed to capture sediment and debris. Other potential pollutants from construction include oil, grease, and chemicals. Readers can use the informa- tion in Table 4 as well as the following subsections on deicing/anti-icing chemicals and construction to consider possible treatment needs when planning for improve- ments in stormwater man- agement, including selection and design of GSI BMPs. This information can be consid- ered when reading the spe- cific BMP descriptions in Step 4 of this guidebook.

Airport Area Activities Pollutants Associatedwith the Area Possible Pollution in Runoff References/ Sources of Information Apron/ramp, flight operations Deicing, refueling, preparing the plane for subsequent flights (e.g., lavatory servicing), and painting. Deicing chemicals, lavatory waste, and fuel (e.g., from overtopping during aircraft refueling). Increased chemical oxygen demand (COD) and 5-day biological oxygen demand (BOD5) and increased concentrations of glycols, oil and grease, total petroleum hydrocarbons (TPH), and metals (e.g., copper, zinc, chromium). Microbial contaminants. Sulej et al. 2012; Nunes et al. 2011; Port of Seattle 2014; Gnecco et al. 2008. Maintenance areas (hangars, garages, outdoor parking) Aircraft storage and maintenance, equipment storage and maintenance, and hazardous materials storage (mostly inside, may be some outside). Solvents, cleaning agents, diesel, gasoline, paint, deicing/anti-icing chemicals, lavatory chemicals, lubricants. Runoff may have BOD5, COD, oil and grease, TPH, total Kjeldhal nitrogen (TKN), among other constituents. Port of Seattle 2014; Sulej et al. 2012; Rowan County Airport 2011. Fueling operations (fuel farms, parking for tankers, etc.) Bulk storage of jet fuel and heating oil, bulk unloading/loading, dispensing of fuel for aircraft fueling tankers and ground service equipment. Jet fuel and other petroleum fluids, due to leaks and spills. Oil and grease, TPH. Nunes et al. 2011. Runways and taxiways Aircraft landing, takeoff, and taxiing; tire rubber removal; and (pavement) deicing. Metals (e.g., copper, zinc, chromium) and (pavement) deicing chemicals. Pollutants documented in runoff from runways include COD, BOD5, total suspended solids (TSS), TKN, and TPH. Sulej et al. 2012. Apron or dedicated deicing area as well as pavement areas Deicing and anti-icing of aircraft pavement, storage of deicing and anti-icing products. Propylene glycol and ethylene glycol. Products for pavement may also include urea, potassium acetate, sodium acetate, sodium formate, and potassium formate. Increased BOD5, growth of nuisance bacteria, and ammonia toxicity to aquatic organisms (if urea is used). Shi 2008; FAA AC 150/5300-14B, AC 150/5220-18A, AC 150/5200-30B, AC 120-60B. Aircraft washing racks Cleaning of aircraft exterior (generally at GA airports). Dirt/residue on aircraft exterior and cleaning solutions. TSS, oil and grease. City of Santa Monica Airport SWPPP, revised 2014. Table 4. Pollutants associated with airside land uses.

28 Green Stormwater Infrastructure References and Other Information Sources • U.S. EPA. 2005. Stormwater Phase II Final Rule: Construction Site Runoff Control Minimum Control Measure. https://www3.epa.gov/npdes/pubs/fact2-6.pdf. • McGormley et al. 2011. ACRP Report 43: Guidebook of Practices for Improving Environmental Performance at Small Airports. Transportation Research Board of the National Academies. Landside Land Uses Landside areas of the airport include terminals, parking lots, access roads, and areas occupied by commercial tenants (e.g., car rental companies). These areas will be subject to many of the same runoff pollution issues as properties outside of the airport setting (e.g., parking lots and landscaped areas associated with commercial or residential areas). Table 5 summarizes pollutants associated with landside airport areas and the potential effects of those pollutants on runoff water quality. It also provides some examples of contaminant concentrations in airport runoff as reported in the literature. Because of the similarities between landside land uses and other non-airport land uses, the following information makes use of the more general literature on stormwater runoff in urban areas. As with all stormwater runoff, readers of this guidebook should bear in mind that concentrations in runoff will vary widely due to a number of variables including the specific practices and amounts of traffic at the airport, storm size and intensity, and antecedent conditions (number of dry days). GSI Screening Matrices The matrices provided in this section for landside-only (Table 6), airside-only (Table 7), and either landside or airside (Table 8) airport land use are to help airports to begin assessing which GSI BMPs may be feasible at their facility. Using the area where they have stormwater concerns (e.g., runway, terminal, parking lots) and some basic information about their regional climate, airports can develop and review a short list of potential GSI BMPs. Additional information for each BMP noting maintenance requirements, possible regulatory issues, and other site-specific considerations can help the reader to narrow down the list of appropriate BMPs. Follow-up information for each BMP type is provided in Step 4, where airports can learn more about the BMPs of interest and begin to evaluate those BMPs in the context of information compiled in Step 2 and the evaluation of runoff concerns in Step 3. Step 5 will guide airports through a careful evaluation of the BMPs of interest as they use all rel- evant information to conduct discussions with other airport staff as well as external stakeholders. Readers can use the informa- tion in Table 5 to consider possible treatment needs when planning for improve- ments in stormwater man- agement in their landside areas, including selection and design of GSI BMPs. This information can be consid- ered when reading the specific BMP descriptions in Step 4 of this guidebook.

Airport Area Pollutant Sources Associated with the Area Possible Pollutants in Runoff References/ Sources of Information Parking garages and parking lots, roadways Oil leaks, vehicle and tire wear, road salt or other deicing and anti-icing chemicals, antifreeze leaks. Oil and grease, total petroleum hydrocarbons (TPH), heavy metals (copper, zinc, chromium), chloride, ethylene glycol, propylene glycol. Oregon Department of Environmental Quality; Oregon State University et al. 2006; NRC 2009. Vehicle washes Soaps, detergents, residue on vehicle exterior (tracking of pollutants outside of wash racks). Particulates, oil and grease, TPH. City of Santa Monica Airport SWPPP, revised 2014. Vehicle fueling stations Fuel. Oil and grease, TPH, heavy metals (copper, zinc, chromium). Oregon State University et al. 2006. Landscaped areas Pesticides and herbicides. Pesticides and herbicides, nitrogen, and phosphorus. U.S. EPA 1983; NRC 2009. Construction areas Soil and sediment. Total suspended solids (TSS). Shaver et al. 2007; U.S. EPA 1983. Solid waste collection/ food waste Oils, grease, trash, food particles, dumpster leachate. Oil and grease, TSS, 5-day biological oxygen demand (BOD5). City of Santa Monica Airport SWPPP, revised 2014. On-site commercial properties (e.g., car rental) Parking and processing of vehicles, cleaning and washing of vehicles. TSS, BOD5, chemical oxygen demand (COD), copper, lead, zinc. Shaver et al. 2007; U.S. EPA 1983. Miscellaneous material storage areas Storage of materials for construction or maintenance. Oil and grease, TSS, and others depending on materials. Table 5. Pollutants associated with landside land uses.

Sand Filters 6 Sediment loads not excessive Low to moderate T, M Potential wildlife attractant if standing water persists Not arid or excessively hot Green Roofs 2 Relatively flat roof Moderate V Potential wildlife attractant More than 12 inches of rain/year Bioswales 8 Slope adequate to avoid standing water Low T, Sed, V Acceptable within runway safety and taxiway safety areas if slope meets FAA safety area requirements, potential wildlife attractant when there is standing water Wet climates Wetland Treatment Systems 9 High water table or wet climate Low to moderate V Potential creation of a wildlife attractant Airport Area Climate Potentially Suitable GSI BMP Number Hydrology and Other Site Considerations Effort Required for Maintenance Expected Maintenance Activities Regulatory Issues to Address During Design Commercial Buildings (Landside) All climates Bioretention 1 Sediment loads not excessive Moderate T, M, V, St Potential wildlife attractant Infiltration Galleries 4 Water table not too shallow, permeable soils, no underlying groundwater or soil contamination Low to moderate T None Sand Filters 6 Sediment loads that are not excessive Low to moderate T, M Potential wildlife attractant if standing water persists More than 12 inches of rain/year Bioswales 8 Slope adequate to avoid standing water Low T, Sed, V Potential wildlife attractant when there is standing water Wet climates Wetland Treatment Systems 9 High water table or wet climate Low to moderate V Potential wildlife attractant Parking Lot (Landside) All climates Bioretention 1 Sediment loads not excessive Moderate T, M, V, St Potential wildlife attractant Infiltration Galleries 4 Water table not too shallow, permeable soils, no underlying groundwater or soil contamination Low to moderate T None Porous Pavement 5 Sediment loads not excessive Moderate to high Sed, St, V Load capacity Sand Filters 6 Sediment loads not excessive Low to moderate T, M Potential wildlife attractant if standing water persists More than 12 inches of rain/year Bioswales 8 Slope adequate to avoid standing water Low T, Sed, V Acceptable within runway safety and taxiway safety areas if slope meets FAA safety area requirements, potential wildlife attractant when there is standing water Wet climates Wetland Treatment Systems 9 High water table or wet climate Low to moderate V Potential wildlife attractant Terminals (Landside portion) All climates Bioretention 1 Sediment loads not excessive Moderate T, M, V, St Potential wildlife attractant Harvesting and Reuse 3 None Moderate to high Sed, St, V Potential wildlife attractant, local plumbing codes, and water rights laws Infiltration Galleries 4 Water table not too shallow, permeable soils, no underlying groundwater or soil contamination Low to moderate T None V = Vegetation – all forms of vegetation maintenance, including replacement, pruning, and mowing M = Media – replacement or other maintenance of media such as mulch, soil, and sand T = Trash – removal of trash St = Structural – maintenance of inflows, drains, outlets, and gutters Sed = Sediment – management of sediment via vacuuming or sweeping, or removal of accumulated sediment Table 6. GSI best management practices for landside-only airport areas.

Screening GSI Best Management practices 31 Airport Area Climate PotentiallySuitable GSI BMP Number Hydrology and Other Site Considerations Effort Required for Maintenance Expected Maintenance Activities Regulatory Issues to Address During Design Parking Areas (Airside) All climates Infiltration Galleries 4 Water table not too shallow, permeable soils, no underlying groundwater or soil contamination Low to moderate T None Sand Filters 6 Sediment loads not excessive Low to moderate T, M Potential wildlife attractant if standing water persists More than 12 inches of rain/year Bioswales 8 Slope adequate to avoid standing water Low T, Sed, V Acceptable within runway safety and taxiway safety areas if slope meets FAA safety area requirements, potential wildlife attractant when there is standing water All but the driest climates Filter Strips 7 None Low V Potential wildlife attractant, mowing height dictated by FAA regulations Ramp/Apron (Airside) All climates Infiltration Galleries 4 Water table not too shallow, permeable soils, no underlying groundwater or soil contamination Low to moderate T None All but the driest climates Filter Strips 7 None Low V Potential wildlife attractant, mowing height dictated by FAA regulations Runways (Airside) More than 12 inches of rain/year Bioswales 8 Slope adequate to avoid standing water Low T, Sed, V Acceptable within runway safety and taxiway safety areas if slope meets FAA safety area requirements. Potential wildlife attractant when there is standing water All but the driest climates Filter Strips 7 None Low V Potential wildlife attractant, mowing height dictated by FAA regulations Taxiways (Airside) More than 12 inches of rain/year Bioswales 8 Slope adequate to avoid standing water Low T, Sed, V Acceptable within runway safety and taxiway safety areas if slope meets FAA safety area requirements, potential wildlife attractant when there is standing water All but the driest climates Filter Strips 7 None Low V Potential wildlife attractant, mowing height dictated by FAA regulations V = Vegetation – all forms of vegetation maintenance, including replacement, pruning, and mowing M = Media – replacement or other maintenance of media such as mulch, soil, and sand T = Trash – removal of trash Sed = Sediment – management of sediment via vacuuming or sweeping, or removal of accumulated sediment Table 7. GSI best management practices for airside-only airport areas.

32 Green Stormwater Infrastructure Airport Area Climate PotentiallySuitable GSI BMP Number Hydrology and Other Site Considerations Effort Required for Maintenance Expected Maintenance Activities Regulatory Issues to Address During Design Facility Buildings (Landside or airside) Not arid or excessively hot Green Roofs 2 Relatively flat roof Moderate V Potential wildlife attractant All climates Harvesting and Reuse 3 None Moderate to high Sed, St, V Potential wildlife attractant, local plumbing codes, water rights laws Roadways (Landside or airside) All climates Bioretention 1 Sediment loads not excessive Moderate T, M, V, St Potential wildlife attractant Infiltration Galleries 4 Water table not too shallow, permeable soils, no underlying groundwater or soil contamination Low to moderate T None Porous Pavement 5 Sediment loads not excessive Moderate to high Sed, St, V Load capacity Sand Filters 6 Sediment loads not excessive Low to moderate T, M Potential wildlife attractant if standing water persists More than 12 inches of rain/year Bioswales 8 Slope adequate to avoid standing water Low T, Sed, V Acceptable within runway safety and taxiway safety areas if slope meets FAA safety area requirements, potential wildlife attractant when there is standing water All but the driest climates Filter Strips 7 None Low V Potential wildlife attractant, mowing height dictated by FAA regulations Wet climates Wetland Treatment Systems 9 High water table or wet climate Low to moderate V Potential wildlife attractant V = Vegetation – all forms of vegetation maintenance, including replacement, pruning, and mowing M = Media – replacement or other maintenance of media such as mulch, soil, and sand T = Trash – removal of trash St = Structural – maintenance of inflows, drains, outlets, and gutters Sed = Sediment – management of sediment via vacuuming or sweeping, or removal of accumulated sediment Table 8. GSI best management practices for landside or airside airport areas.