Effluent Guidelines for Construction

1. Effluent Guidelines for Construction Greg DavisUSEPAdavis.gregory@epa.gov

2. EPA promulgated Construction and Development effluent limitations guidelines December 1, 2009. • New rule requires all construction sites subject to permits to implement erosion and sediment controls and pollution prevention measures

3. What is an ELG? • Technology-based standards for control of wastewater and stormwater discharges from various categories of industry • Where ELGs are not sufficient to meet water quality, water quality based effluent limitations may apply.

4. 2-Part ELG for Construction • Erosion and Sediment Control Requirements (BMPs) applicable to all permitted sites • Numeric limits – 280 NTU limit applicable to larger projects

5. Phased Approach for Numeric Limits • Numeric effluent limits apply to: • 20+ acre sites on August 1, 2011 • 10+ acre sites on February 2, 2014 • Requirements must be incorporated into state permits whenever permits are re-issued (Colorado’s permit expires in 2012)

6. What About Existing Projects? • For existing projects covered by general permits, the rule would apply whenever a new general permit is issued and that project applies for coverage under the new permit • For existing project covered by individual permits, the permitting authority can wait until a new general permit is issued to issue a new individual permit

7. Erosion and Sediment Control Requirements • Control stormwater volume and velocity within the site to minimize soil erosion; • Control stormwater discharges to minimize erosion at outlets and downstream channel and streambank erosion; • Minimize the amount of soil exposed during construction; • Minimize the disturbance of steep slopes; • Design, install and maintain erosion and sediment controls considering factors such as precipitation and soil characteristics; • Provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas to increase sediment removal and maximize stormwater infiltration, unless infeasible; and • Minimize soil compaction and, unless infeasible, preserve topsoil.

8. Soil Stabilization and Dewatering Requirements • Initiate stabilization of disturbed areas immediately whenever any clearing, grading, excavating or other earth disturbing activities have permanently ceased, • Initiate stabilization immediately when earth disturbing activities have temporarily ceased and will not resume for a period exceeding 14 calendar days. • In arid, semiarid, and drought-stricken areas where vegetative stabilization is infeasible, alternative stabilization measures must be employed. • Discharges from dewatering activities, including discharges from dewatering of trenches and excavations are prohibited unless managed by appropriate controls.

9. Pollution Prevention Requirements • Minimize the discharge of pollutants from equipment and vehicle washing, wheel wash water, and other wash waters. Wash waters must be treated in a sediment basin or alternative control that provides equivalent or better treatment prior to discharge; • Minimize the exposure of building materials, building products, construction wastes, trash, landscape materials, fertilizers, pesticides, herbicides, detergents, sanitary waste and other materials present on the site to precipitation and to stormwater; and • Minimize the discharge of pollutants from spills and leaks and implement chemical spill and leak prevention and response procedures.

10. Prohibited Discharges • Wastewater from washout of concrete, unless managed by an appropriate control; • Wastewater from washout and cleanout of stucco, paint, form release oils, curing compounds and other construction materials; • Fuels, oils, or other pollutants used in vehicle and equipment operation and maintenance; and • Soaps or solvents used in vehicle and equipment washing.

11. Surface Outlets • When discharging from basins and impoundments, utilize outlet structures that withdraw water from the surface, unless infeasible.

12. Turbidity Limitation and Monitoring • Limit is based on polymer-assisted settling, but permittees can use any technology • Turbidity limitation of 280 NTUs is a Daily Maximum Value • Daily value at each discharge point is calculated by averaging all samples at that point • Individual samples can be above 280 NTU as long as average is below 280 NTU • Permittees can phase land disturbing activities to stay below the disturbed acreage threshold

13. Technologies for Turbidity Control • Settling (basins or check dams) • Filtration • In-ground sand filter • Geotextile bags • Practices in channels (fiber check dams, geotextile products) • In many cases polymer or flocculant addition may be necessary

14. Turbidity Limitation and Monitoring • Limitation does not apply to interstate natural gas pipeline projects • Limitation does not apply on days with precipitation exceeds the local 2-year, 24-hour storm event • Sampling required at each discrete discharge point (basins, channels, pipes, etc.)

15. Sampling Requirements • Monitoring frequency is up to the permitting authority, but EPA recommends at least 3 grab samples per day at each discharge point (during normal working hours) • For linear projects, permitting authority can consider representative sampling instead of sampling at each discharge point • Even if permitting authority allows representative sampling, all discharge points are still subject to compliance with effluent limitation

17. Questions ?