At the end of 2009, the U.S. Environmental Protection Agency (EPA) published effluent limitations guidelines (EGLS) and new source performance standards (NSPS) to control storm water runoff and the discharge of pollutants from construction sites. The new regulations took effect on February 1, 2010, requiring all permits issued by the EPA to incorporate the new requirements.
New Maximum Numeric Turbidity Limitations
For the first time, the EPA has set numeric limits for the discharge of storm water from construction sites. The EPA has set a maximum daily average numeric limit of 280 NTU (a turbidity measurement) for covered sites.
In case you don’t know, Wikipedia defines Turbidity as:
Turbidity is the cloudiness or haziness of a fluid caused by individual particles (suspended solids) that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.
The turbidity limitations will effect construction sites on a phase-in schedule. Construction sites with 20 or more acres of earth disturbance must comply starting August 2, 2011, and those sites with 5 or more acres of earth disturbance must comply starting February 2, 2014.
Covered sites must monitor the storm water discharge for turbidity, report the results of the monitoring and use control technologies (which are not defined) to ensure that the maximum levels are not exceed.
Other Changes (Non-Numeric BMPs)
The EPA has identified other mandatory Best Management Practices (BMPs) relating to: (i) Erosion and Sediment Controls (40 CFR § 450.21(a)); (ii) Soil Stabilization (40 CFR § 450.21(b)); (iii) Dewatering (40 CFR § 451.21(c)); (iv) Pollution Prevention Measures (40 CFR § 450.21(d)); and (v) Prohibited Discharges (40 CFR §450.21(e)).
Additional Resources
