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.
The MPCA explains that 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. Severe erosion can threaten buildings, roads and bridges.
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 is not feasible, 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. The reissued permit goes into effect Aug. 1. For more information on the new permit, visit the MPCA’s Construction Stormwater webpage (www.pca.state.mn.us/wfhya5b).
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