Stormwater Permitting at Airports Julianne Rantala MPCA, Industrial Division

Stormwater at Airports Stormwater Construction Stormwater Industrial Stormwater

Construction Stormwater Construction areas Groundwater/dewatering

When is a permit Needed for Construction Stormwater? You need an NPDES/SDS permit if you are the owner or operator for any construction activity disturbing: One acre or more of soil. Less than one acre of soil if that activity is part of a "larger common plan of development or sale" that is greater than one acre. Less than one acre of soil, but the MPCA determines that the activity poses a risk to water resources.

What type of Construction Stormwater Permit is needed? Most construction activities are covered by the general NPDES stormwater permit for construction activity, but some construction sites need individual permit coverage. – General Construction Stormwater Permit (MNR100001), expires 8/1/08. – Individual Permit with Stormwater Coverage Owners and operators are both responsible for submitting the permit application.

General Permit for Construction Stormwater Stormwater Pollution Prevention Plan (SWPPP) must be submitted with permit application and implemented prior to beginning construction. List of BMPs. Temporary Sediment Basins. Permanent Stormwater Management System. Erosion Prevention Practices. Sediment Control Practices. Inspections and Maintenance. Final Stabilization. Discharges to “Special Waters” have additional requirements.

Stormwater Pollution Prevention Plan (SWPPP) for Construction Stormwater Incorporated into the final plans and specs for the project, including on standard plates. Location, type and description of erosion prevention and sediment control BMPs. Site map with existing and final grades, location of areas not to be disturbed, areas of phased construction and waters of the state. Description of temporary sedimentation and/or permanent stormwater management system, if required. Identification of knowledgeable person and chain of responsibility for short and long-term implementation and maintenance. Methods used for final stabilization.

Examples of BMPs Riprap at inlet/outlet Vegetative Buffer

Temporary Sediment Basins Required if 10 or more acres are disturbed and drain to a common area. Required to be provided until final stabilization. Provide storage capacity for the calculated runoff from a 2 year, 24-hour storm from each acre or 3,600 ft 3 of storage per acre, if no calculation. Design specifications in permit. Equivalent sediment controls -- such as smaller sediment basins, and/or sediment traps, silt fences, vegetative buffer strips or any combination of appropriate measures. Dewatering and basin draining authorized under specific conditions.

Permanent Stormwater Management System Required if the project’s ultimate development replaces pervious surface with one or more acre of cumulative impervious surface. A volume of ½ inch of runoff from the impervious surface from the project must be treated by one of the management methods prior to leaving the site. Management Methods: – Wet sedimentation basin – Infiltration/Filtration – Regional Ponds – Combination of Practices Special provisions for feasibility of installation of methods (up to 3 acres or 1% of project size), proximity to bedrock and availability of right-of-way in road projects. FAA circular 39 implications.

Inspections and Maintenance for Construction Stormwater Once every 7 days during active construction and within 24 hours of a rainfall event greater than 0.5 inches in 24 hours. Stabilized areas of project can be reduced to 1x/month. Inspect erosion prevention and sediment control BMPs for integrity and effectiveness. – Silt fences repaired/replaced/supplemented when non-functional or within 1/3 the height of the fence. – Sediment removed from basins when ½ the storage volume. – Surface waters, construction entrances, infiltration areas for evidence of sedimentatioin. Document inspections; retain records.

Silt Fence Management This…

Sedimentation Basin

Final Stabilization Permittee is required to ensure final stabilization of site. Submit Notice of Termination within 30 days of final stabilization. Final stabilization means: – All soil disturbing activities at the site have been completed and soils stabilized by a uniform perennial vegetative cover of 70% over pervious surface. – Removal of all temporary synthetic and structural BMPs, such as silt fencing – Returning agricultural land to its preconstruction agricultural use – Removal of sediment from temporary basins that are to be used as permanent management systems.

BMPs Minimize vehicle tracking from site Slope stabilization

Forms and Resources Application forms, including on-line permit application and notice of termination: – Special Waters lists and information: – Alternative Stormwater Treatment Systems: – Compliance Assistance Toolkit for Small Construction Operators: – Minnesota Stormwater Manual – Inspection Checklist: –

Industrial Stormwater Significant areas and activties Aircraft de-icing and anti-icing fluids (ADAFs) – Propylene glycol, other additives Pavement deicers – Urea, sand Fuel spills/releases – Jet fuel, diesel fuel, gasoline Parking lot maintenance – Salt, sand Ground water sumps/pumpout

When is a permit needed for Industrial Stormwater? A permit is required if: Stormwater is in contact with “significant materials”, AND Stormwater is leaving – discharged – from the site.

What type of Industrial Permit is needed? Individual Permit with Stormwater Coverage General Industrial Stormwater Permit (MNG610000), expired 10/31/02 Other Regulatory Activity: ELGs for Deicing Operations (EPA) (8/2000) Multi-Sector General Permit (MSGP) (expired 10/30/05, 12/1/05 draft)

Individual Permit Individual permit can be required if: Reasonable potential to violate WQ standard, contribute to an impairment or if facility would be more adequately permitted under an individual permit Would likely have monitoring and/or limits for analytes that have reasonable potential to be present in stormwater.

General Industrial Stormwater Permit Standard requirements for industries in certain SIC codes: 4512 Scheduled air transportation 4513 Air courier services 4522 Nonscheduled air transportation 4581 Airports, flying fields, and airport terminal services Mandatory and discretionary SIC codes in expired permit – No Exposure Exclusion in 2002 draft. Requires SWPPP implementation prior to facility being covered by permit. Also requires BMPs implemented, inspection, reporting/recordkeeping. Currently no monitoring required.

Stormwater Pollution Prevention Plan (SWPPP) for Industrial Stormwater Drainage map: significant areas and materials, directions of runoff, location of waters of the state. Inventory of exposed significant materials that may potentially contact stormwater. Evaluate areas of exposure. Listing and description of BMPs that will be used to minimize or eliminate pollution of stormwater at the site: source reduction, diversion, treatment. Evaluate discharge conveyances from the site. Preventive maintenance program. Spill prevention and response procedure. Employee training program.

Inspections and Maintenance for Industrial Stormwater Conducted 1x every 2 months during non-frozen conditions, with at least one inspection during the reporting period during discharge. Conducted by trained personnel. Purpose: – Determine whether BMPs require maintenance or changes – Completeness and accuracy of the SWPPP Document inspections; retain records. Make any corrective actions within 30 days.

ELGs for Airport Deicing Operations Effluent limitation guidelines (ELGs) are being developed by EPA. Involves gathering data on the engineering, economic and environmental impact aspects of airport deicing operations. Data collection activities include – airport site visits, – field sampling and analysis of airport wastewater/stormwater, – administering industry questionnaires, – consultations with other federal agencies and state agencies, – reviewing permit files and monitoring data gathered by airports, and – reviewing technical and scientific literature. Preliminary data summary published in 8/2000 (EPA-821-R ). Deicing questionnaire sent to industry 4/2006. Schedule: proposed rule in 12/2007; final action by 9/2009. More information at:

Multi-Sector General Permit (MSGP) The MSGP provides facility-specific requirements for many types of industrial facilities within one overall permit. The permit outlines steps that facility operators must take prior to being eligible for permit coverage, including development and implementation of a stormwater pollution prevention plan (SWPPP). Placed on public notice on 12/1/05 (through 2/16/06) with Benchmark Monitoring provisions for several types of industries. – Sector S – Air Transportation (SIC codes within major group 45). Sector S had proposed “benchmark monitoring” for BOD, CBOD, Ammonia, pH and TSS at facilities with deicing operations. Many comments on monitoring – criticized for being too extreme, and not far enough More information at:

Forms and Resources General industrial stormwater permit site, including application forms: – Permitting process for individual permits: – MSGP website: – ELG website: – EPA Stormwater Site: – MnDot SWPPP Assistance: – Manual for Storm Water Pollution Prevention Plans for Minnesota Airports (2/93) – Peter Buchen, MnDOT Aviation