New rules protect lakes, streams from construction runoff

For release: July 9, 2013

Contact: Cathy Rofshus, 507-206-2608

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New rules protect lakes, streams from construction runoff

St. Paul, Minn. -- Protecting lakes and streams from construction runoff is the purpose of a statewide permit recently approved by the Minnesota Pollution Control Agency (MPCA) Citizens’ Board.

Construction runoff can contain pollutants, such as sediment that fills in lakes and wetlands, nutrients that fuel algal blooms, and chemicals harmful to fish and other life. The volume of runoff can also be a problem. As land is developed with buildings, parking lots and roads, more rainwater and snowmelt are drained to local waters. That increase in flow can erode stream beds and banks, leading to more erosion, habitat loss and other problems. Severe erosion can threaten buildings, roads and bridges.

The general permit for construction stormwater aims to protect lakes and streams in two ways. The first is through temporary practices during construction to manage runoff. The second is through permanent treatment of additional runoff.

Under the new permit, developed sites can no longer discharge the first inch of new runoff downstream. Instead, property owners must allow for rainwater and snowmelt to soak into the ground, such as through rain gardens or porous pavement. If this infiltration is infeasible, then they need to use other techniques, such as green roofs and collection for irrigation, to capture the runoff.

This general permit is part of the MPCA’s program under the federal Clean Water Act and Minnesota law to manage stormwater. When construction site owners and operators apply for coverage under the general permit, they agree to comply with the conditions set in the permit.

The state first issued a construction stormwater general permit in 1993. This permit must be reissued every five years. Changes in federal and state laws prompted updates to this permit. For example, state laws now support low-impact development to retain and conserve water, meaning a site must mimic its natural hydrology as the landscape is developed.

While the primary changes concern federal and state rules, the changes also include reorganization of the permit language. The reissued permit includes clarifications and minor language changes to make the permit more concise, to delete duplicate or unneeded language, and to make the permit more readable and easier to understand.

In addition, the MPCA will require that permit applications be submitted electronically to achieve greater efficiency. The agency issues 1,000 to 3,000 general construction stormwater permits a year.

The reissued permit goes into effect Aug. 1. It follows a seven-month process of informational meetings and comment period. The MPCA received 57 letters containing about 800 comments on the draft permit. Based on comments, the agency made some revisions to the permit, including keeping one-half inch of rain as the prompt for site inspections, instead of the quarter-inch proposed, and allowing sites to use local weather data instead of maintaining rain gauges on site.

For more information:

• on the MPCA Citizens’ Board presentation and decision, go to the board webpage (http://www.pca.state.mn.us/veiz404).
•  on the new permit, visit the MPCA's Construction Stormwater webpage (http://www.pca.state.mn.us/wfhya5b).
• on low-impact development, visit the Small Business Environmental Assistance Program webpage (http://www.pca.state.mn.us/veiz7d0).

Broadcast version:

Protecting lakes and streams from construction runoff is the purpose of a statewide permit recently approved by the Minnesota Pollution Control Agency Citizens’ Board.

Construction runoff can contain pollutants. The additional drainage from developed sites can also cause erosion and other problems.

This permit aims to protect Minnesota’s waters in two ways. The first is through temporary practices during construction to manage runoff. The second is through permanent treatment of additional runoff, such as letting rainwater and snowmelt soak into the ground through rain gardens and other means.

For more information, visit the M-P-C-A website at www.pca.state.mn.us.

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