The Minneapolis Park and Recreation Board (MPRB) has been monitoring stormwater since the late 1990s. Stormwater runoff from our streets, lawns, and buildings eventually flows into our lakes and creeks. We monitor stormwater flowing through storm sewer pipes and best management practices (BMPs) treatment devices such as wetlands, ponds, grit-chambers, and other structures. We use state of the art equipment and automatic flow-paced samplers and samples are analyzed by an independent laboratory.
As the stormsewers were separated from the sanitary sewers in the Mississippi River drainage area and directed to the rivers, interest in what pollutants are present in the stormwater increased.
National Pollutant Discharge Elimination System (NPDES): The 1977 Clean Water Act gave the Environmental Protection Agency (EPA) the authority to implement pollution control programs for regulating discharges of pollutants into surface waters. With this authority, the EPA created the NPDES program. The EPA has delegated permitting authority for Minnesota's program to the Minnesota Pollution Control Agency(MPCA).
The NPDES program mandates that operators of a Municipal Separate Stormsewer System have a NPDES permit. The MPCA issued the first NPDES Municipal Stormwater Discharge permit for Minneapolis on December 1, 2000. The permit requires Minneapolis to implement approved stormwater management activities. These activities are designed to mitigate the pollution effects of urbanization on stormwater runoff, as well as to provide annual program reporting.
The MPRB and Minneapolis Department of Public Works (MPW) are co-signatories on the NPDES stormwater permit for Minneapolis. The MPW and the MPRB have been joint permit holders since 2001. The purpose of stormwater monitoring is to characterize the impacts of stormwater runoff on the waterways they empty into. Monitoring sites are selected to represent land use sites found in Minneapolis: residential, commercial/industrial, mixed use and parkland.
The MPRB collects stormwater and snowmelt runoff samples throughout the year at various locations in Minneapolis as required by the NPDES permits.
Urbanization has led to drastic changes in the historical patterns of water movement. The use of storm sewers has caused an increase in the amount of water, pollutants and sediment that enter Minneapolis lakes and creeks.
Stormwater BMPs, such as treatment wetlands and ponds, are being used throughout the park system to improve water quality in the lakes and creeks. These structures help counteract the effects of urbanization by allowing for pollutants and sediment to settle out before they reach a water body.
We have been closely involved in the construction of several stormwater treatment ponds and wetlands, including:
View the MPRB Water Resources Report for detailed annual monitoring data, data collection methods, and more.