Environmental Leader

Construction sites will have to limit pollution from water runoff starting in February of 2010 if EPA’s final rule proposal takes effect.

This represents the first time EPA has installed national monitoring requirements and enforceable numeric limitations on construction site stormwater discharges.

About 82,000 construction entities will be affected by the rule, which could add nearly $1 billion in annual costs to projects, reports the Wall Street Journal.

The rule, which would be phased in over four years, is designed to prevent runoff related to construction activities like clearing, excavating and grading. If not properly managed, those practices can lead to soil and sediment washed away from the construction site during storms, polluting nearby waterways, ponds and lakes, EPA says.

The rule (click here for the version that will appear in the Federal Register) will apply to construction sites larger than an acre, and will require construction firms to use best management practices.

Construction sites impacting 10 or more acres of land at a time will have to monitor discharges and ensure compliance with specified limits. Here is a fact sheet (PDF) on effluent limitations guidelines and new source performance standards.

In addition to causing water quality problems, soil runoff from construction reduces the depth of small streams, lakes and reservoirs, EPA says, adding that the water bodies often require dredging.