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C-1 A p p e n d i x C C.1 Seattle-Tacoma International Airport, C-2 C.2 Salt Lake City International Airport, C-8 C.3 Victoria International Airport, C-13 Monitoring Case Studies
C-2 interpreting the Results of Airport Water Monitoring C.1 Seattle-Tacoma International Airport The Seattle-Tacoma International Airport (SEA) case study provides an example of how the Port of Seattle (Port) leveraged its monitoring program to support development of site-specific effluent limits and use of an alternative methodology for designing best management practices (BMPs), which resulted in significantly lower capital investment than would have been required using the standard regulatory methods that do not rely on airport-specific monitoring data. Airport Overview The airport is located just east of Puget Sound between the cities of Seattle and Tacoma in Washington State and is the 13th busiest airport in the United States with over 37 million passengers and 319,000 metric tons of air cargo annually (Port of Seattle, 2015). SEA was originally established in 1944 by the Port to support U.S. efforts in World War II. Airport services were expanded to include scheduled passenger services in 1947 and air freight in 1952. The facility covers more than 2,500 acres and is located approximately 14 mi south of Seattle, Washington. Monitoring Program Overview Stormwater drainage at SEA is separated into two collection systems, the industrial wastewater system (IWS) and the storm drainage system (SDS). The IWS receives stormwater runoff from areas where aircraft servicing, maintenance, and deicing occurs. The Port operates a treatment system to treat runoff in these areas for petroleum and deicing pollutants prior to discharge to Puget Sound. Runoff from a total of 375 acres is diverted to the IWS. The SDS drains the remain- der of the airport property, over 1,200 acres. Approximately one-half of this area is impervi- ous and primarily associated with airport industrial activities. The SDS drainage encompasses 11 drainage basins with outfalls located on the north, west, and south of the property. The north- ern outfalls drain to Miller Creek and Lake Reba, the western outfall drains to Walker Creek, and the southern outfalls drain to Des Moines Creek and the Northwest Ponds. Permit Limitations and Required Monitoring Stormwater discharges at SEA are required to meet the conditions in the airport individ- ual industrial stormwater NPDES permit, WA-002465-1, issued by the State of Washington, Department of Ecology (Ecology). Numeric limitations for airport industrial stormwater runoff discharges through the IWS are described in Table C-1. Parameter Maximum Daily Monthly Average BOD (November through March) 2,665 lb/day 45 mg/L BOD (April through October) 1,480 lb/day 25 mg/L TSS 33 mg/L 21 mg/L Oil and Grease 15 mg/L 8 mg/L pH Daily minimum is equal to or greater than 6, and the daily maximum is less than 9 Flow BOD load Design Criteria Daily Peak Flow of 7.1 MGD Table C-1. SEA numeric limitations for IWS discharges. Key Takeaways ⢠Site-specific metals effluent limits developed using water effects ratio. ⢠Monitoring data used to select and size control measures. ⢠Adaptive management approach using monitoring data to evaluate perfor- mance of existing control measures. ⢠Telemetry used to increase sampling efficiency and consistency and reduce cost. ⢠Modification of automatic samplers to achieve flow-weighted composite. ⢠Root cause analysis for elevated levels of pH.
Monitoring Case Studies C-3 SEA conducts continuous flow monitoring of the IWS discharges and collects daily com- posite samples for biochemical oxygen demand (BOD) and total suspended solids (TSS) analysis, daily grab samples for pH and oil and grease analysis, and two composite samples per year for priority pollutants and heavy metals analysis. SEA also continuously monitors influent to the treatment plant for total organic carbon (TOC), which is used to provide near-real-time assessment of BOD concentration and mass loading. Since SEA treatment processes do not effect BOD concentrations, continuous TOC monitoring is the operational basis for segregating flows projected to exceed IWS effluent limits and therefore pumped offsite for secondary treatment at a local publicly owned treatment work. SEA must also conduct acute toxicity testing and chronic toxicity testing of at least five concentrations of its effluent once in the last summer and once in the last winter prior to the end of its permit coverage. Numeric limitations for airport stormwater runoff discharges through the SDS are described in Table C-2. SEA collects one or two grab samples per quarter, depending on the outfall, for turbidity, pH, and oil and grease analysis; and one or two composite samples per quarter for BOD, ammonia, nitrate/nitrite as N, priority pollutants, and total copper and total zinc analysis. SEA must conduct acute toxicity testing of at least five concentrations of its effluent once in the last summer and once in the last winter prior to the end of its permit coverage. SEA must also conduct in-stream sublethal toxicity testing from Miller Creek, Des Moines Creek, Walker Creek, Northwest Ponds, and Lake Reba downstream near the airport outfalls. Sublethal tox- icity testing must be conducted biannually during the last season of its permit coverage and once additionally during deicing. Monitoring Execution The Port emphasizes consistency in the way that samples are collected, using the same triggers for sampling and the same flow-weighted composite automatic samplers at most locations. A flow-weighted composite sample is the most representative for characterizing concentrations in a single sample analyzed by a laboratory, but the Port regularly experienced overflows of the samplers. The samplers were initially set up to capture a sample aliquot from each level of flow rate and the sample volume was proportioned off of the lowest flow rate. The volume of each sample aliquot was then adjusted based on the flow rate (higher flow rate = larger sample aliquot). The Port determined that the off-the-shelf com- posite automatic samplers were not large enough to capture the volume needed for their 24-hour flow-weighted composite. The Port modified the automatic samplers (Figure C-1) to increase the size of the sample containment volume to allow for 24-hour flow-weighted composites to be collected with the automatic samplers, eliminating the need to have person- nel manually collect sample aliquots throughout the 24-hour period. Parameter Maximum Daily Turbidity 25 NTU pH Between 6.5 and 8.5 Oil and Grease 15 mg/L and no visible sheen Ammonia 14.7 mg/L (only if urea is applied) Nitrate/Nitrite as N 0.68 mg/L (only if urea is applied) Priority Pollutants Report concentration Total Copper 25.6, 28.5,32.2, 47.9, or 59.2 lg/L Total Zinc 71.4 or 117 lg/L Table C-2. SEA numeric limitations for SDS discharges.
C-4 interpreting the Results of Airport Water Monitoring The Port operates a unique telemetry-based system to initiate sample collection for its com- posite samplers. Composite samplers are programmed to start collecting 24-hour composite samples when they receive a signal from a cell dial-up system. The dial-up system was chosen because it does not interfere with FAA communications and because the samplers can then be started remotely when the permit conditions requiring sample collection occur. The air- port has 11 monitoring points within the SDS, and the telemetry-based system represents a significant savings over the alternative, which would require staff to visit each monitoring location separately to initiate the composite samplers, and then again to collect the samples and conduct field analyses. The system also allows sample collection at all stations to start simultaneously resulting in monitoring results across the airport representing the same time period and conditions, eliminating staggered start times with different samplers collecting flow from different stages of the storm event. Issue Definition The airport experienced elevated levels of zinc, copper, and TSS in stormwater discharged through the SDS that at times exceeded permit conditions. As a result, Ecology required SEA to conduct an all known, available, and reasonable methods of prevention, control, and treatment (AKART) analysis, which is a technology-based approach to limiting pollutants from wastewater discharges. Typically an AKART analysis requires an engineering and an economic determina- tion for all contaminants prior to discharge to waters of the state. In 2005, the Port performed an engineering analysis of the SDS, which evaluated stormwater discharges from each of the NPDES drainage subbasins to determine whether AKART require- ments were met or if additional BMPs were needed. The engineering analysis determined that additional BMPs were needed in some subbasins to meet AKART requirements. Additionally, the Port conducted a facility assessment to map existing drainage areas, areas draining to existing structural BMPs, and to identify areas where industrial activities are con- ducted. As a result of this effort, the Port determined that the elevated levels of zinc, copper, and TSS in stormwater could be attributed to galvanized rooftops and guardrails, and runway areas with accumulated aircraft tire tread worn off by repeated aircraft touchdowns. Figure C-1. Modified automatic samplers.
Monitoring Case Studies C-5 Issue Resolution The Port used a three-step approach to resolve the regulatory compliance issue stemming from elevated concentrations of zinc, copper, and TSS in stormwater discharges: ⢠Development of site-specific effluent limits ⢠Selection and sizing of BMPs ⢠Adaptive management Airport monitoring data facilitated decisions made in each of the three steps described in the following subsections. Development of Site-Specific Effluent Limits The Port worked with Ecology to use the water effects ratio approach established by U.S. EPA to develop site-specific metals criteria. The water effect ratio accounts for the difference between the toxicity of the metal in laboratory dilution water and its toxicity in waters receiv- ing airport discharges. Samples were collected from in-stream sites located downstream of air- port discharge outfalls during all four seasons including the critical summer low-flow period. The samples were spiked with various concentrations of metals and side-by-side toxicity tests were performed with laboratory dilution water. The water effect ratio was then calculated by dividing the site constructed downstream water lethal concentration by the laboratory dilution water lethal concentration. The site-specific criteria were further adjusted to account for hard- ness and the ratio of the dissolved fraction to total metal present in the receiving waters. As a result of this study, Ecology adjusted the metals criteria on a site-specific basis using the water effects ratio approach. Selection and Sizing of BMPs To identify specific BMPs necessary to meet AKART requirements and water quality objec- tives, the Port hired a consultant to analyze the monitoring data for copper, zinc, lead, TSS, and turbidity over time for the monitored subbasins. The consultant analyzed the data for three dif- ferent time periods (1994â2004, 1997â2004, and 2003â2004) to identify if changes in land use or implementation of existing best management practices resulted in changes in the discharges of these constituents. For each time period, subbasin, and constituent, the consultant identified the minimum and maximum values, created a histogram of the data set, and graphed the cumulative distribution of the data set. An attainment analysis was then conducted using the existing monitoring data to evaluate the ability of various BMPs to reduce concentrations of the constituents below benchmarks. An expected range of concentration for each constituent in each subbasin after implemen- tation of a BMP was estimated by multiplying the removal efficiency for the BMP by the existing cumulative distribution plot for each constituent. The BMP cumulative distribution for each subbasin and constituent was then compared to several benchmarks, including the following: ⢠U.S. EPA multi-sector general permit benchmark ⢠Acute water quality standard for copper, lead, and zinc ⢠Minimum site-specific water quality standard derived from laboratory-derived water effect ratios ⢠Minimum biotic ligand modelâderived water quality standard If 99 percent of the values in the BMP cumulative distribution for the subbasin and constitu- ent were below the benchmark then the benchmark was considered to be met for that BMP. For water quality standards, attainment was defined as 1 exceedance in 36 samples, which translates to 97 percent attainment (Parametrix, 2005). The Port developed a subsequent engineering
C-6 interpreting the Results of Airport Water Monitoring report for Ecology proposing new BMPs that would enable attainment of AKART and water quality objectives. Adaptive Management The Port decided to take an adaptive management approach to stormwater controls. An ini- tial set of new BMPs and improvements to existing BMPs were constructed in response to engi- neering report recommendations. The airport prioritized the easiest and most cost-effective changes first, which were the source reduction controls. These controls included coating of metal rooftops and guardrails and specifications for new buildings to reduce use of zinc and copper. Major improvements included integration of runway infields as filter strip treatment areas, construction of media filtration vaults and wetpool control measures to treat heavy load- ing subbasins, integration of engineered treatment swales along roadways and other areas as land use allowed, and construction of flow detention ponds and vaults. As part of the adaptive management program and stormwater pollution prevention plan, the Port regularly reviews monitoring data to assess the effectiveness of stormwater BMPs at meet- ing the water quality objectives. Elevated levels of pH were experienced periodically in the open ponds. The Port initially thought that the elevated pH might have been a nutrient issue, but subsequent monitoring identified the growth of algae in the dead storage portions of the ponds. As a result, base flow was routed around the detention ponds to allow the filters to dry, reducing the algae growth. A separate instance of high pH was traced to crushed concrete fines used in a rebuilt runway. The Port traced the root cause of the elevated pH by starting at the outfall where elevated pH was initially measured and then monitoring upstream points in succession, working backwards upstream through the drainage system to identify the location contributing the high pH runoff, where the concrete crusher was situated. New BMPs have been added and improvements to existing BMPs have been made to increase effectiveness, including enhanced bioretention/media treatment swales with a media layer for metals removal, energy dissipation in a wet pond to prevent re-suspension of sediment during storm events, and rotating use of the two oyster shell media filtration vaults to maximize filtra- tion and facilitate filter replacement. Planning for additional BMP needs identified as part of the monitoring program have also been integrated into airport construction projects, including relocating catch basins further from the edge of the runway effectively lengthening filter strips as part of the runway reconstruction project. Table C-3 provides a summary of structural BMPs within each subbasin. Lessons Learned Ecology states in the SEA permit fact sheet that âover the past two permit cycles the Port has invested over $80 million in stormwater infrastructure improvements through the construction of AKART BMPs followed by an adaptive management program. This investment has led to water quality improvements that are evident in the overall high attainment of permit effluent limits and low variability in STIA stormwater dataâ (Department of Ecology, 2014). The Port has made significant investment in stormwater infrastructure and feels that use of monitoring data has allowed for a more efficient use of airport funds for improving water quality at the airport. The use of the water effect ratio allowed Ecology to develop site-specific limits for metals, which reduced the level of investment in BMPs needed. The use of the exist- ing monitoring data to evaluate, select, and size appropriate BMPs allowed the Port to tailor the investments in BMPs to more closely match what would be needed to meet the AKART and water quality objectives. The use of adaptive management allowed the airport to make an initial capital investment and then subsequent investments to adjust as necessary instead of potentially
Monitoring Case Studies C-7 Subbasin Runoff Characteristics Control Measures Miller Creek SDN-1 flight kitchens, roads, and the roofs of several buildings Painted galvanized rooftops reduce zinc concentrations in stormwater. Bioswales along Air Cargo Road treat runoff from this roadway. Stormwater detention pond detains and treats stormwater for flow control. Bioretention swale and solar pump system provide additional treatment during the summer months. SDN-2 taxiways and cargo ramp areas Runoff collected and diverted to the IWS. SDN-3 service roads, runways, taxiways, and associated infield areas Portions of the infields are managed as filter strips to treat runoff from the adjacent runways. SDN-4 service roads, runways, taxiways, and associated infield areas Catch basins relocated further away from the edge of the runway lengthening the effective treatment area of the filter strips. SDN-3A runway and taxiways Flow-control detention pond and filter strips located along the runway. SDW-1A taxiways Flow-control detention pond and filter strips located along the runways. SDW-1B runway and taxiways Flow-control detention pond and filter strips located along the runways. Des Moines Creek West SDS-3/5 runway, taxiway, limited/maintenance access roadways and runway infield Bioswales for stormwater treatment. Two flow-control detention facilities. Existing filter strips were improved through edge dam removal, regrading, and reseeding and widened to provide additional stormwater treatment. SDS-4 runways, taxiways, and service roads Runway filter strips provide water quality treatment. Flow-control pond provides detention. Catch basins were moved farther away from the edge of the runway, lengthening the effective treatment area of the filter strips. Bioretention/media bed swale was constructed west of the detention pond to provide additional treatment. SDS-6/7 runways, taxiways, infield, and perimeter roads Flow-control vault provides detention. Filter strips and bioswales treat runoff from the runways and taxiways. Des Moines Creek East SDS-1 aircraft maintenance building rooftops, parking areas, cargo building rooftops, roads, and parking lots Painted galvanized rooftop and portions of HVAC-I-beam superstructure reduce zinc concentrations in stormwater. Two bioswales to treat runoff. Conversion of one bioswale into a bioretention media bed with an underdrain system. Modifications were made to the flow splitter to allow the ability to effectively direct flows to the modified bioretention swale for additional stormwater treatment. SDE-4 roads, parking lots, terminal area roofs, and taxiways SE Pond Tunnel Diversion Pipe diverts flows from existing 60-inch storm drain pipeline to segregate the subbasin stormwater from city of SeaTac drainage and conveys airport stormwater to a separate detention and treatment site. Enhanced flow-control extended detention pond, a 600-cartridge media filtration vault providing enhanced treatment, and a bioswale. A gravity drain system was added to the pond to allow the dead storage volume to be routed to an adjacent bioretention/media treatment swale during the summer. SDD-06A public roads, vehicle parking areas, rooftops, Port Bus Maintenance Facility and Distribution Center, landscaped areas, and construction laydown Bioretention swales with oyster shells placed at the end for additional treatment. Oil-water separators. Flow-control detention pond. Walker Creek Basin SDW-2 runway, taxiways, and infield areas Runway filter strips provide treatment. Flow control is provided by a detention pond. ⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠⢠Table C-3. SEA control measures.
C-8 interpreting the Results of Airport Water Monitoring over-designing initial BMPs. These three steps allowed the Port to effectively leverage its moni- toring program to reduce the total cost of improvements over what would have been required using more traditional methods. References Department of Ecology (2014). Fact Sheet for NPDES Permit WA0024651. Lacey, WA: Washington State. Parametrix (2005). CSMPrg Water Quality Data for Engineering Report: NPDES Subbasin Attainment. Memorandum. Bellevue, WA. Port of Seattle (2015). About the Port, Port of Seattle website. Accessed on September 21, 2015. http://www. portseattle.org/About/Pages/default.aspx. C.2 Salt Lake City International Airport This case study illustrates how a monitoring-based pilot study was used to explore innovative new approaches for deicer management at Salt Lake City International Airport (SLC), resulting in regulator buy- in and implementation of a permanent deicer management system that achieved significant annual cost savings for the Salt Lake City Depart- ment of Airports. While the monitoring performed in this case study was focused on groundwater and soil, the lesson learned is also transfer- able to stormwater monitoring applications. Airport Overview Salt Lake City International Airport is the busiest airport in Utah and the 27th busiest in the United States (by passenger count), with over 20 million passengers per year and approximately 900 daily aircraft operations in 2014. The airport is located approximately 4 mi outside of downtown Salt Lake City, Utah. SLC is a public transportation terminal that leases space and provides services to airline companies and other support services. SLC is owned by the Salt Lake City Corporation, and is operated and managed by the Salt Lake City Department of Airports (SLCDA). The airport was originally constructed as an air field in 1911, and has expanded over the years to include four runways and a total land area exceeding 8,000 acres. The airport serves as a major hub for Delta Airlines and Delta Connection carrier SkyWest Airlines. The air- port hosts a variety of general aviation facilities and activities, which comprise nearly 20% of all aircraft movements at SLCDA. Additionally, the Utah Air National Guard (UANG) operates the Salt Lake City Air National Guard Base at SLC. Other major facilities at the airport include an aircraft rescue and firefighting training facility, a Boeing manufacturing facility, a SkyWest Airlines maintenance and training facility, and a Delta TechOps hangar and maintenance facility. The Utah Department of Environmental Quality (UDEQ) Division of Water Quality (DWQ) administers permit programs associated with the Utah Pollutant Discharge Elimination System (UPDES), including stormwater associated with industrial activities. There are three general water- sheds for the drainage of stormwater at SLC and five UPDES-permitted stormwater outfalls. Drain- age Basin 1 discharges to the City Drain Canal (Outfall 001). Drainage Basins 2, 3, and 5 discharge to the Surplus Canal (Outfalls 002, 003, 004, and 005). Drainage Basin 4 drains to the City Drain Canal under normal conditions but is pumped to the Surplus Canal during high flow conditions Key Takeaways ⢠Concentration-based segregation of deicing runoff for recycling and land application. ⢠Monitoring-based pilot study dem- onstrated ability to land-apply low- concentration deicing runoff without impacting groundwater. ⢠Regular monitoring after land applica- tions to verify degradation of deicing materials. ⢠Monitoring results supported expan- sion of system to serve recycling process wastewaters.
Monitoring Case Studies C-9 (Utah DWQ, 2014a). A portion of the north end of SLC property drains overland via a natural shallow gradient through grass and marsh towards the Great Salt Lake (Utah DWQ, 2014a). The City Drain Canal is classified by UDEQ as protected for infrequent primary contact recreation (Class 2B) and as a severely habitat-limited water (Class 3E). The Surplus Canal is classified by UDEQ as protected for secondary contact recreation (Class 2B); protected for warm water species of game fish and other aquatic life (Class 3B); protected for waterfowl, shore birds, and other water-oriented wildlife (Class 3D); and protected for agricultural uses (Class 4). The Surplus Canal is very close to the impairment threshold for dissolved solids (salts) (Landrum & Brown, 2009). Both the Surplus Canal and the City Drain Canal (by way of the Sewage Canal) drain to the Great Salt Lake. DWQ also administers ground water discharge permits in accordance with Utah Administra- tive Rules for Ground Water Quality Protection [Utah Administrative Code (UAC) R317-6]. The airport overlies a shallow unconfined groundwater aquifer, which is approximately 4 to 10 ft below the surface (Landrum & Brown, 2009). SLC has experienced drainage issues related to a high groundwater table, including groundwater infiltration into the SLC storm sewer sys- tem (Utah DWQ, 2014a). The aquifer is classified by the state as Class IV Saline Ground Water, in accordance with UAC R317-6-4.7. Protection levels are established for various parameters in UAC R317-6-2.1 that are applicable to this aquifer, including metals and volatile organic chemicals (Utah DWQ, 2014b). Background concentrations of these parameters in the aquifer are reportedly below the groundwater quality standard for metals and detection limits for regu- lated volatile organic chemicals (Utah DWQ, 2014b). A protection level does not apply for total dissolved solids (TDS), because Class IV Saline Ground Water is associated with background concentrations of TDS exceeding 10,000 mg/L. The protection level established for propylene glycol is equivalent to the detection limit. Monitoring Program Overview SLC maintains an individual discharge permit for stormwater associated with industrial activ- ities (excluding UANG) under the UPDES. The UPDES permit establishes stormwater effluent limits for oil and grease and pH at Outfalls #001â#005 and, for flow, 5-day biochemical oxygen demand (BOD5), total suspended solids (TSS), and TDS at Outfalls 002â005. Discharge moni- toring is required to be performed at each outfall and reported on a monthly basis in the form of a discharge monitoring report. Grab samples are required to be collected for all parameters except for flow. Flow is required to be analyzed âinstantaneously,â which means that a single measurement is required. BOD and TSS are reported as 7-day and 30-day average limits; TDS, flow, and oil and grease are reported as daily maximums; and pH is reported as a daily minimum. The SLC UPDES permit was most recently reissued in March 2014. The land application activities are also performed in accordance with Ground Water Dis- charge Permit No. UGW35005. This permit, which was most recently updated with the expan- sion of land application activities in 2014, establishes monitoring requirements to protect the aquifer underlying the airport. The ground water discharge permit requires groundwater quality monitoring to be performed semi-annually at four monitoring wells located near SLCâs three on-site storage lagoons used to store collected deicing stormwater runoff. The land application site is required to be monitored annually after each deicing season using two additional ground- water monitoring wells. Groundwater samples are required to be analyzed for pH, conductivity, TDS, propylene glycol, and total petroleum hydrocarbons. Sampling is conducted by SLCDA staff that are certified for groundwater sampling (Salt Lake City Department of Airports, 2002). Groundwater levels are also monitored and if levels rise to within 2.5 ft from the surface, land application activities are stopped (Utah DWQ, 2014b).
C-10 interpreting the Results of Airport Water Monitoring Additionally, the ground water discharge permit requires soil sampling for propylene glycol at the land application site, to monitor for effects on subsurface soils (Utah DWQ, 2014b). Sam- pling is performed 5 to 7 days after the application to allow time for the glycol to biodegrade (SLCDA, 2002). During each soil monitoring event, soil samples are collected from each of the three application areas, including sampling at four random sites determined using a random number generator. Samples are collected at various depths, including at the surface, at a depth of 1â1.5 ft, and at a depth of 2â2.5 ft, using a hand auger (SLCDA, 2002). If propylene glycol is detected in any of the random samples, the sampling is repeated after a period of 1 to 2 days (SLCDA, 2002), and this process is repeated until all samples are nondetect, before allowing land applications to resume. Sampling is conducted by SLCDA staff that are certified for soil sampling (Salt Lake City Department of Airports, 2002). Issue Definition The SLC deicer management program involves the use of deicing pads to collect spent aircraft deicing fluid (ADF) commingled with stormwater runoff. Collected runoff is diverted to one of three lined 3-million gal storage lagoons for temporary storage. Stormwater with a sufficiently high concentration of glycol is routed into an on-site waste glycol recycling facility for process- ing by the airport. However, large volumes of low-concentration stormwater are also collected (including flows collected at the start and tail end of deicing events), and these flows are unable to be processed economically within the waste glycol recycling facility. Until 2001, this dilute stormwater was routinely discharged to the sanitary sewer in accordance with an industrial pre- treatment permit from the Salt Lake City Corporation Department of Public Utilities (SLCDA, 2014). This approach was determined to be unsustainable over the long term due to steep annual fees associated with discharges to the sanitary sewer, as well as public odor complaints associated with the degradation of deicing materials within the sanitary sewer. SLCDA thus sought out an alternative approach for disposal of the low-concentration runoff and identified land application as a potentially preferable option. SLCDA staff coordinated with the regulator in 2001 to get approval to perform a land application pilot study. The objective of the pilot study was to examine the viability of a permanent land application system, with consideration for the degradation rates of ADF in soil over time, and the potential for impacts to underlying soil and groundwater. With regulatory approval, the pilot study proceeded in two phases in the fall of 2001. The first phase was a benchtop lab experiment to determine appropriate fluid application rates. The goal was to determine what application rates would avoid saturating the soil within 3 ft of the surface and prevent the transmission of applied fluids into groundwater. Soil from the site was tilled and collected into multiple 5 gal buckets. Collected fluid was then applied to the soil at application rates that varied between buckets, and the fluid was given time to drain into the soil until it reached a point of equilibrium. Fluid depths were measured in the soil for each application rate, and application rates meeting the defined criteria were selected for use in the second phase of the pilot study (SLCDA, 2002). The second phase involved a pilot-scale field experiment, in which collected fluid was applied to a 10 ft by 10 ft area on-site where the soil was tilled. After a single application, soil sampling was performed on a daily basis at various locations and depths using a hand auger and hand-driven soil probe. Each 10 g soil sample was combined with 10 mL of water, which was then shaken and filtered to separate out sample water and sediment. The sample water was then analyzed for eth- ylene glycol using gas chromatography with flame ionization detection (SLCDA, 2001). Results showed that concentrations decreased with increasing depth from the surface, as expected based on the saturation levels of the collected fluid in the soil. Results demonstrated that average ethyl- ene glycol concentrations decreased as degradation occurred over time (SLCDA, 2001).
Monitoring Case Studies C-11 Results of the pilot study were immediately submitted to DWQ for review and approval, along with a proposal to implement a full-scale land application system on a temporary basis, with ongoing monitoring activities. Monitoring results showed that glycol concentrations reached nondetect levels within a 1-week time frame after land application, and degraded at a soil depth above the groundwater table (SLCDA, 2002). It was also determined that degradation was most efficient within dry soils. The results were consistent with published literature values for the degradation rates of ethylene glycol in soil (SLCDA, 2002). Issue Resolution In 2002, a formal permit application was submitted to DWQ for land application of ADF with <1 percent glycol. In response to the permit application, DWQ modified the existing SLCDA groundwater discharge permit to allow land application of ADF. The permit specified criteria related to the permanent land application system, application rates and timing, monitoring requirements for soil and groundwater, and required monthly reporting. The land application system was implemented with three central pivot-style irrigation sprinklers (Figure C-2), each with a radius of 200 ft and having the capacity to apply up to 500,000 gal of fluid per 24-hour period. Sample ports were incorporated into the piping lead- ing to the on-site lagoons, to allow stormwater flows to be more precisely segregated by glycol concentration. High-concentration flows (glycol > 1 percent) are diverted to one lagoon for recycling, while low-concentration flows are diverted to a separate lagoon for land application. Low-concentration fluid is then pumped to a temporary storage tank and then pumped to one of three pivots for land application. Based on the monitoring findings from the pilot study, land application is limited to warmer months to improve glycol degradation rates and limit the potential for ground saturation. Land application events typically occur between April and August, although they may extend as late as October if the weather allows and there is a need. As previously described, soils at the application sites are monitored on a regular basis following application events to confirm non- detect levels before additional applications are allowed to occur. Groundwater is monitored at groundwater wells on a semi-annual basis to confirm that groundwater does not contain levels of glycol or other parameters in excess of groundwater quality standards (Utah DWQ, 2014b). Glycol has not been detected in the groundwater samples since the land application system was implemented. Figure C-2. Pivot-style irrigation sprinklers.
C-12 interpreting the Results of Airport Water Monitoring With the continued success of the permanent system, SLCDA received regulatory approval to expand the system in 2014 (Figure C-3). Each of the three pivots was increased in size from a 200 ft radius to a 400 ft radius, with the land application area expanding from 28 to 34 acres (Utah DWQ, 2014b). The application rate per acre was maintained based on the findings from the pilot study, but the total land application volume was expected to increase from approxi- mately 3 million gal/year to approximately 7 million gal/year, based on the increased land appli- cation area (Utah DWQ, 2014c). The increased land application capacity allowed SLCDA to begin land application of process wastewaters from the glycol recycling operation, in addition to continued application of low-concentration stormwater. The process wastewaters, which include reject water from the ion exchange regeneration process and reverse osmosis-polished condensate from the mechanical vapor recompression process, were previously discharged to the sanitary sewer (SLCDA, 2014). The expanded land application system effectively eliminated the discharge of deicing-related fluids to the sanitary sewer, which was previously incurring costs of over $39,000 annually (based on 7.2 million gal discharged in 2012). Lessons Learned The primary lesson learned with respect to implementation of the land application system was the value of using a monitoring approach to explore the viability of new stormwater man- agement approaches and gain regulatory buy-in. The monitoring results collected during both Figure C-3. Land application system showing 2014 expansion.
Monitoring Case Studies C-13 phases of the pilot study, and as part of ongoing land application activities, were critical for dem- onstrating to the regulator that the land application approach would be sufficiently protective of the environment. The monitoring results also informed the planning and design of the land application system, including the selection of land application rates and frequency, allowing the system to perform as expected when implemented on a larger scale. Ultimately the monitoring allowed for SLCDA to achieve significant annual costs savings with respect to deicer manage- ment activities, eliminating annual deicing-related sanitary sewer discharge fees. References Landrum & Brown (2009). Salt Lake City International Airport Environmental Assessment: Light-Rail Transit Line. May. Salt Lake City Department of Airports (2002). Permit Application for Land Application of Glycol at the Salt Lake City International Airport. November 1. Salt Lake City Department of Airports (2001). Proposal to Perform Land Application of Collected Material from Glycol Recycling Plan. October 26. Salt Lake City Department of Airports (2014). Salt Lake City Department of Airports Deicing Fluid Reclamation Plant Wastewater Discharge Permit SLC-0013. August 6. Utah Division of Water Quality (2014a). UPDES Permit No. UT0024988. State of Utah Department of Environ- mental Quality, March 14. Utah Division of Water Quality (2014b). Ground Water Discharge Permit No. UGW350005. State of Utah Department of Environmental Quality, June 9. Utah Division of Water Quality (2014c). Statement of Basis: Salt Lake City Department of Airports Ground Water Discharge Permit Modification. DWQ-2014-005122. State of Utah Department of Environmental Quality, May. C.3 Victoria International Airport The Victoria International Airport (YYJ) case study provides an example of how an airport without dedicated environmental staff was able to apply its water quality monitoring program to identify a contamination issue, conduct a root cause analysis, and successfully address the source of the contamination. Monitoring data was used to justify the need for innovative mitigation measures, as well as confirm that the cause of contamination had been sufficiently controlled. The mitigation measures ultimately had a positive effect on the quality of water discharging from the airport drainage system, as well as on water quality in a receiving stream that provides important habitat for salmon and trout. Airport Overview Victoria International Airport is the 10th busiest airport in Canada and the 2nd busiest airport in British Columbia, with over 1.7 million passengers per year and over 120 daily flights. The airport is located in British Columbia on southern Vancouver Island, between North Saanich and Sidney. It is approximately 25 km (16 mi) north of Victoria, the capital of British Columbia. YYJ was originally established as Patricia Bay Airport in 1939, addressing the need for a large military airport to support World War II operations and training, accommodating the Royal Canadian Air Force, Royal Air Force, and Royal Canadian Navy. Airport services expanded to include scheduled passenger services in 1942. In 1997, airport owner Transport Canada Key Takeaways ⢠Heavy metal contamination identi- fied through trend analysis on historic monitoring data. ⢠Monitoring used to define extent of contamination in stream. ⢠Root cause analysis to isolate source of heavy metal contamination in drainage system. ⢠Monitoring used to confirm source addressed with removal of historic storm system sediment. ⢠Stream restoration project imple- mented, with ongoing monitoring to demonstrate benefits.
C-14 interpreting the Results of Airport Water Monitoring transferred airport operations to the newly established Victoria Airport Authority (Kerr Wood Leidal, 2013). The airport property covers over 485 hectares and is divided into two watersheds. The major- ity of the airport drains to Reay Creek, which drains to the southeast into Bazan Bay. Remain- ing portions of the airport drain to TenTen Creek, which drains to the west into Patricia Bay (Victoria International Airport, 2011). The airport drainage system consists of a combination of open channels and established storm pipe networks that drain to the two natural water- courses. Both of the receiving waters are small streams with a history of contamination due to heavy metals and other pollutants (Victoria International Airport, 2011). The contamination is potentially associated with historic military base activities at the airport, as well as a variety of historical and ongoing industrial, commercial, and agricultural activities within the water- shed, including a cadmium plating facility and two Transport Canada dump sites on the Federal/National Dumpsite Remediation priority list (Victoria International Airport, 2011). Reay Creek provides important habitat for coho salmon and sea run cutthroat trout, among other types of fish (Davis, 2014). Monitoring Program Overview The YYJ Source Control Program for water quality monitoring is one component of the over- all YYJ environmental program, which is described in the 2011 Environmental Management Plan. While the environmental program is intended to facilitate compliance with environmen- tal regulations, the Victoria Airport Authority (VAA) Board of Directors have established a clear objective to âlead the way in environmental managementâ (Victoria International Airport, 2011) and go beyond meeting minimum environmental standards (Bogusz, 2013). The Source Control Program is specifically targeted at monitoring stormwater that drains to Reay Creek and TenTen Creek, from airport sources as well as nearby commercial and agricultural lands. Monitoring activities currently include the collection of samples from a fixed station within each of the receiving streams, as well as supplemental sampling at various locations within the airport drainage system using portable samplers (Victoria International Airport, 2011). While the airport does not have a formal written monitoring plan, it consistently performs monitor- ing activities as they have been performed historically, while adapting procedures as needed to monitor the effects of potential pollutant sources and activities within the watershed. Regulatory requirements encompassed by the YYJ environmental program include the Cana- dian Environmental Protection Act (CEPA), Canadian Council of Ministers of the Environ- ment (CCME), British Columbia Environmental Management Act, Capital Regional District Sanitary Source Control By-Law, Fisheries Act, Federal Halocarbon Regulations, and Storage Tank Systems for Petroleum Products Regulations (Victoria International Airport, 2011). YYJ stormwater discharges are required to comply with the Canadian Environmental Quality Guide- lines (EQGs), a broad set of national environmental criteria pertaining to water, soil, air, and other environmental media, which was established by CCME in 1996. As a component of the EQGs, the Canadian Water Quality Guidelines (originally established in 1987) provide specific water quality criteria pertaining to the protection of freshwater and marine aquatic life as well as agricultural, drinking, recreational, aesthetic, and industrial water uses. The EQGs are based on a principle of having âno observable adverse effects on atmospheric, aquatic, and terrestrial ecosystems over the long termâ (CCME, 2014). Additionally, VAA is required to comply with a total glycol discharge limit of 100 mg/L, as established by the CEPA (Transport Canada, 2011). The VAA Operations Department has historically conducted in-stream sampling at each of the two receiving stream fixed stations, which are located near the downstream airport property line. Each station includes an automatic sampler that is set up to collect a 24-hour composite
Monitoring Case Studies C-15 sample on a weekly basis. The sample is analyzed for a variety of parameters, including total suspended solids, metals, nutrients, glycol, oil and grease, and water hardness. A handheld water quality multi-meter is used to monitor in-stream parameters such as pH and temperature. Addi- tionally, in-stream samples are collected on a quarterly basis upstream of airport discharges, where receiving stream tributaries cross onto airport property. The upstream samples are ana- lyzed for similar constituents as the downstream samples, to allow for a review of differences in receiving stream water quality across the airport, as well as an assessment of potential airport or non-airport contributions to water quality issues (Transport Canada, 2011). VAA staff also perform water quality monitoring at airport drainage system outfalls using a portable sampler (Victoria International Airport, 2011). This type of monitoring is a relatively newer addition to the Source Control Program and was added for the purpose of characterizing the water quality of discharges from various potential pollutant sources on airport lands, includ- ing ongoing or sporadic industrial activities. VAA has taken precautions to minimize backflow from receiving streams into the airport drainage system by installing end caps on airport drainage system outfalls. These end caps allow several additional inches of water level rise in the stream before the outfalls and sampling locations become submerged. Glycol monitoring is performed at select outfalls during winter deicing events, collecting three samples over the course of 24 hours. These samples are analyzed for compliance with CEPA criteria (Transport Canada, 2011). Monitoring results are compiled by the lab using an online software, enabling the data to be accessed directly by VAA staff. Although VAA did hire a consulting firm to assist with review of monitoring data for a period of time, it was decided that VAA should take on this effort to save budget for remediation and other activities. The monitoring results are downloaded by VAA staff and imported into Microsoft® Excel⢠to allow the graphing of data and identification of changes in water quality or unexpected results, potential exceedances of CCME or CEPA water quality cri- teria, and trends in water quality over time that might indicate an ongoing issue. The data review and compilation does not include statistical analyses. If results indicate a potential water quality issue, VAA staff may investigate the source of the issue or collect additional monitoring data to confirm the results. Monitoring data is also periodically compiled and summarized for review by upper management or the VAA Board of Directors. Glycol monitoring results are required to be submitted to Transport Canada annually at the end of the deicing season, but other water quality monitoring data is not required to be reported to any regulatory agencies. Issue Definition A heavy metal contamination issue was discovered based on a review of historic weekly in-stream water quality monitoring data dating back to 1997. The results for the Reay Creek in-stream monitoring point showed consistently high concentrations of five to six different metals, including cadmium and zinc. These results regularly exceeded CCME water quality criteria and, on select occasions, exceeded British Columbia Contaminated Sites Regulation criteria under the British Columbia Environmental Management Act. Additional in-stream monitoring was conducted to confirm these results, and the new data was consistent with historical findings. From there, additional monitoring was conducted systematically in the form of a root cause analysis. Sediment samples were collected from the Reay Creek stream bed, and these were found to be contaminated with similar heavy metals. Regular monitoring was then initiated at airport outfalls, and results from a few select outfalls were found to have consistently high concentra- tions, suggesting that the source may be within airport lands or the airport drainage system. Monitoring proceeded upstream of those outfalls at internal points within the airport drainage system, including locations upstream and downstream of potential industrial sources of pollut- ants. These samples did not point to a clear source of contamination, due to consistently high
C-16 interpreting the Results of Airport Water Monitoring concentrations being widespread throughout the drainage system. As a next step, VAA staff conducted sampling of sediment within the storm pipes and found high concentrations of heavy metals. After consultation with the maintenance department, it was concluded that the storm system had not been cleaned in recent years, and the sediment may have been present for a long period of time. VAA proceeded with cleaning out the storm system to remove the contaminated sediment. Follow-up sampling was performed at airport outfalls and the results came back clean, suggest- ing that the primary source of contamination had been addressed. Outfall monitoring continued over several years, and contamination levels were much lower, indicating that there was not an ongoing airport source of heavy metals. The root cause of contamination was attributed to a historic spill or industrial activity that led to heavy metals being captured in sediment deposits within the pipes, and then leaching out over a long period of time. Further compounding the issue is that much of the storm system at Victoria is quite old and in need of repairs, and many of the sections are cracked or collapsed, allowing the ingress of potentially contaminated ground- water. Although the source of contamination was historic, VAA continues to monitor outfalls periodically to watch for any changes in the quality of stormwater discharges. Issue Resolution With the completion of the root cause analysis and the cleanout of the airport drainage system storm pipes, a significant source of the ongoing contamination had been identified and addressed; however, it was discovered that the storm drain system itself was in a partially failed state and additional pollution coming through sedimentation would continue to affect in-stream water quality as well as Reay Creek Pond downstream. Core samples of stream sediment were collected to characterize the extent of contamination in the stream, and an initiative was spearheaded to restore Reay Creek. It was necessary to demonstrate the need for the stream restoration project to VAA upper management, Board of Directors, and Chief Executive Officer. The results of the root cause analysis (showing that the sediment removal had reduced the airport source of contamination) were critical in demonstrating that the stream restoration project could proceed as it would reduce the amount of future stream contamination leaving airport property. Although there was no regulatory pressure, VAA initiated the Reay Creek Restoration Project voluntarily and proactively, with consideration for benefits to fish habitat, the environment, and the downstream community of Sidney. Historic contamination of Reay Creek and Reay Creek Pond (from a variety of potential sources) was becoming a hot button issue within the com- munity and had the potential to create political pressure to address the issue. VAA performed public outreach and collected letters of support for the project from the community. Project goals included the following: ⢠Reducing concentrations of heavy metals and other pollutants in storm water runoff ⢠Improving stream water quality ⢠Improving stream and riparian habitat to allow for restoration of fish habitat in the future ⢠Incorporating a means for emergency spill containment ⢠Implementing the project in a manner that would not increase the attraction of hazardous wildlife (Victoria Airport Authority, 2013). The stream restoration concept was developed in January 2012 and was coordinated with the Department of Fisheries and Oceans to obtain required permits for stream work (Victoria Airport Authority, 2013). The design team was led by Kerr Wood Leidal Associates, Ltd., with environmental consulting support from SLR Consulting, Ltd., and landscaping support from Murdoch de Greef, Inc. Construction was completed in October 2012 by Draycor Construction
Monitoring Case Studies C-17 Ltd. Overall, the remediation effort cost $232,000 (Victoria Airport Authority, 2013). The project involved isolating the most contaminated segment of stream (approximately 175 m in length) with a berm, and converting it into a bioremediation wetland (Victoria Airport Author- ity, 2013). The wetland design included the removal of pockets of contaminated sediment from this segment, while creating an opportunity for the remaining sediment to be treated in-situ (Bogusz, 2013). Outside of the isolation berm, a new stream channel (Figure C-4) was cut into the south slope of the original stream to allow upstream flows to pass around the wetland, including flows from airport and upstream properties. The new stream channel was enhanced with riparian plantings, riffles, and pools to help restore aquatic wildlife habitat. The wetland is isolated with a manual gate at both the upstream and downstream ends. The upstream gate remains closed during normal operations to allow upstream flows to bypass the wetland (Figures C-5 and C-6). The downstream gate is normally open to allow the discharge of flows that continue to enter the wetland, including drainage from two airport outfalls; however, Figure C-4. View of newly constructed bypass channel, looking upstream (west), with bypassed stream segment/wetland (vegetated area) visible on the right side of photo. Figure C-5. View of newly constructed bypass channel, looking downstream (east), showing upstream manual gate that remains closed to route flows around wetland (trees in center).
C-18 interpreting the Results of Airport Water Monitoring it is able to be closed to provide emergency spill containment in the event of unforeseen releases (Victoria Airport Authority, 2013). The wetland provides treatment for discharges from these outfalls, in addition to providing treatment for the remaining contaminated stream sediment (Bogusz, 2013). Water quality monitoring data shows that pollutant levels within the new stream channel are at very low levels. Downstream of the bioremediation wetland, concentrations of heavy metals have been significantly reduced and are anticipated to show continuous improvement as the wetland becomes more established (Bogusz, 2013). As a result of the project, VAA received positive feedback in the press and from members of the community and environmental and fishing groups, including the Peninsula Streams Society and Sidney Anglers (Figure C-7). Airports Council Internationalâ North America awarded VAA with its 2013 Environmental Achievement Award for the Reay Creek Restoration Project (Kerr Wood Leidal, 2013). In recent years, there has been evidence of increasing numbers of salmon returning to Reay Creek to spawn (Heywood, 2012). Figure C-6. Bypass channel and upstream wetland gate after construction complete. Figure C-7. Fish observed within Reay Creek since project completion.
Monitoring Case Studies C-19 Lessons Learned Although the contamination associated with this case study was ultimately attributed to historic sources rather than current airport activities, VAA did identify several lessons learned through this experience that were applicable to its ongoing Source Control Program. As a result, the monitoring program and procedures have been adapted with considerations for these lessons learned. One key lesson was that it is important to collect sufficient data to support decision mak- ing. Data quality may be affected by a variety of variables, and so it is important to have a large enough data set to be able to identify outliers and overall trends over time. Initial monitoring results may point to something that is ultimately not supported by a larger data set. It is impor- tant to investigate the issue systematically, rather than react based solely on initial results. It may be necessary to collect a larger data set to be able to isolate variables and confirm that an issue exists or has been addressed. VAA expanded its monitoring program to include outfall moni- toring as a result of the Reay Creek investigation and continues to perform regular outfall and in-stream monitoring to this day. New monitoring results are regularly compared to the exist- ing data set to identify potentially unexpected results and watch for potential trends over time. Another lesson learned was to be flexible and vigilant with the monitoring program. Although monitoring is expensive, the money is well spent if it helps to manage risks that may be more costly to address in the long run. VAA has adapted its monitoring program to monitor for indicator parameters potentially associated with ongoing activities in the watershed, including those not associated directly with airport activities, to identify the potential for future impacts to the stream. As an example, it coordinated with its lab to identify parameters associated with agricultural runoff, and it performs monitoring for this âfarming sample packageâ when par- ticular farming activities such as manure spreading are being performed within the watershed. This sample package includes total suspended solids, electro-conductivity, metals, chloride, nitrite/nitrate, orthophosphate, fecal coliform, and sulfate. Additionally, VAA has adapted its monitoring location for glycol based on a determination that the in-stream sample location was not adequate for detecting glycol discharges, due to dilution and distance downstream. The monitoring location has been relocated to an outfall downstream of ongoing deicing activities. References Bogusz, J. (2013). Reay Creek Restoration Project. Victoria Airport Authority. Canadian Council of Ministers of the Environment (2014). Canadian Environmental Quality Guidelines. http://www.ccme.ca/en/resources/canadian_environmental_quality_guidelines/index.html. Davis, T. (2014). The Fishing Fix. Fishing. June. pp. 64â69. Heywood, S. (2012). Salmon Return to Reay Creek. BC Local News, November 13. http://www.bclocalnews.com/ news/178238701.html. Kerr Wood Leidal (2013). Victoria Airport Authority Wins Award for Reay Creek Enhancement Project. Septem- ber 12. http://www.kwl.ca/news/victoria-airport-authority-wins-award-reay-creek-enhancement-project. Transport Canada (2011). Chapter 13: Environmental. TP 14052: Guidelines for Aircraft Ground-Icing Operations. Victoria Airport Authority (2013). Reay Creek Remediation Project. Presentation. September 22. Victoria International Airport (2011). Environmental Management Plan.
