A State’s Perspective of the EPA’s Effluent Limitations Guidelines 40 CFR Part 450 Jeffrey B. Shaver, PE, CPESC AASHTO Subcommittee On Design July 27, 2010

Applicability Discharges associated with construction activity required to obtain NPDES permit coverage New Source Performance Standards (NSPS) apply to all new sources Reflecting The Best Available Demonstrated Control Technology Construction Activity including clearing, grading, and excavation that disturbs 5 or more acres Less than 5 acres if part of a larger common plan that will ultimately disturb 5 or more acres. Effective February 1, 2010 All other sources covered under Best Practicable Technology Currently Available (BPT) Best Available Technology Economically Achievable (BAT) Best Conventional Pollutant Control Technology (BCT) Effective February 1, 2010

The new requirements must be incorporated into any new general or individual permits issued after February 1, 2010 TN CGP is being reissued Fall 2010 Implementation Dates February 1, 2010 – Non-numeric effluent limitations NSPS, BPT, BAT, BCT August 1, 2011 – Numeric effluent limitation for construction sites that disturb 20 or more acres NSPS, BAT February 2, 2014 – Numeric effluent limitation for construction sites that disturb 10 or more acres NSPS, BAT

Erosion and Sediment Controls Control stormwater volume and velocity within the site to minimize soil erosion Control storm discharges, including both peak flow rates and total stormwater volume, to minimize downstream channel and stream bank erosion Minimize the amount of soil exposed during construction activity Minimize the disturbance of steep slopes

Erosion and Sediment Controls Minimize sediment discharges from the site. The design, installation and maintenance of erosion and sediment controls must address factors such as the amount, frequency, intensity and duration of precipitation, the nature of resulting stormwater runoff, and soil characteristics, including the range of soil particle sizes expected to be present on the site

Erosion and Sediment Controls Provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas to increase sediment removal and maximize stormwater infiltration, unless infeasible Minimize soil compaction and unless infeasible, preserve topsoil

Soil Stabilization Stabilization of disturbed areas must, at a minimum, be initiated immediately whenever any clearing, grading, excavating or other earth disturbing activities have permanently ceased on any portion of the site, or temporarily ceased on any portion of the site and will not resume for a period exceeding 14 calendar days. Stabilization must be completed within a period of time determined by the permitting authority. In arid, semiarid, and drought-stricken areas where initiating vegetative stabilization measures immediately is infeasible, alternative stabilization measures must be employed as specified by the permitting authority.

Dewatering Discharges from dewatering activities, including discharges from dewatering of trenches and excavations, are prohibited unless managed by appropriate controls.

Pollution Prevention Measures Design, install, implement, and maintain effective pollution prevention measures to minimize the discharge of pollutants. At a minimum, such measures must be designed, installed, implemented and maintained to: 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 Minimize the discharge of pollutants from spills and leaks and implement chemical spill and leak prevention and response procedures.

Prohibited Discharges The following discharges are prohibited: 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 Soaps or solvents used in vehicle and equipment washing. Surface Outlets When discharging from basins and impoundments, utilize outlet structures that withdraw water from the surface, unless infeasible.

Average turbidity of any discharge for any day must not exceed 280 NTU daily maximum Conduct monitoring consistent with requirements established by the permitting authority. Each sample must be analyzed for turbidity in accordance with methods specified by the permitting authority. If stormwater discharges in any day occur as a result of a storm event in that same day that is larger than the local 2-year, 24-hour storm, the effluent limitation does not apply for that day.

At least three grab samples, representative of a discharge, shall be collected for the duration of each discharge event. The first grab sample should be taken during the first 30 minutes of the discharge. If the collection of a grab sample during the first 30 minutes is impracticable, a grab sample can be taken during the first hour of the discharge. The minimum time period between representative grab samples shall be 30 minutes. Permittees may sample the turbidity in their discharges multiple times over the course of a day and the average of all measurements should not exceed the average daily value limitation.

Samples and measurements taken in compliance with the monitoring requirements specified herein shall be representative of the volume and nature of the monitored discharge, and shall be taken after treatment and: Prior to mixing with uncontaminated storm water runoff or the receiving stream Prior to effluent leaving the construction site boundary The numeric limitation applies to all discharges from construction sites. However, diffuse stormwater, such as non-channelized flow through a silt fence or other perimeter control that infiltrates into a vegetated area, and does not then discharge to surface waters, would not generally require sampling. Sampling should be conducted, at a minimum, during normal business hours at a project. The working day can generally be considered to be between the hours of 6 a.m. and 6 p.m., or when workers are normally present on the construction site.

When a linear construction site has two or more outfalls that must be sampled and the permittee reasonably believes outfalls discharge substantially identical effluents, the permittee may monitor the effluent of one of such outfalls. The permittee shall select a representative outfall conveying stormwater runoff from the largest disturbed area for that discharge event. The permittee shall report on the monitoring report that the quantitative data also applies to the substantially identical outfall(s).

The permittee shall evaluate the results obtained from sampling and monitoring to determine whether the facility complies with effluent limitations. If the results of stormwater runoff monitoring demonstrate that the site has exceeded the limitation, the permittee must review its storm water pollution prevention plan, make any modifications or additions to the plan which would assist in reducing effluent concentrations to less than the monitoring limitations, including a timetable for implementation.

TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU Trace 44 Enhanced Rock Check Dam Photo & Data Provided By: Civil and Environmental Consultants, Inc.

Enhanced Rock Check Dam TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU 0.6 inches/ 4 acres 625 Photo & Data Provided By: Civil and Environmental Consultants, Inc.

Enhanced Rock Check Dam TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU 0.6 inches/ 4 acres 289 Photo & Data Provided By: Civil and Environmental Consultants, Inc.

TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU 0.6 inches/ 15 acres Rock Check Dams 1 Enhanced Rock Check Dam Photo & Data Provided By: Civil and Environmental Consultants, Inc.

3 Rock Check Dams 1 Enhanced Rock Check Dam TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU 0.6 inches/ 15 acres 662 Photo & Data Provided By: Civil and Environmental Consultants, Inc.

TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU 0.1 inch/ 7 acres 103 Silt Fence With Wire Backing Sediment Tubes (Wattles) Photo & Data Provided By: Civil and Environmental Consultants, Inc.

TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU 0.1 inch/ 3.5 acres 57 Silt Fence Sediment Tubes (Wattles) Photo & Data Provided By: Civil and Environmental Consultants, Inc.

TOTAL RAINFALL/ WATERSHED ACREAGE AVERAGE DAILY NTU 0.1 inch/ 4 acres 237 Silt Fence Photo & Data Provided By: Civil and Environmental Consultants, Inc.

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