Monitoring and Analysis
Water quality and stormwater monitoring provides valuable information on the health of lakes, rivers & streams in Minneapolis. It helps to identify problems and is used to measure the effectiveness of efforts to minimize pollution. Primary targets for monitoring include City lakes, streams, wetlands, as well as stormwater runoff.
The Minneapolis Park and Recreation Board (MPRB) performs extensive water quality monitoring and data collection as part of efforts to protect and care for the 13 lakes, three streams and one river in Minneapolis. This work is documented each year.
The Annual Water Resources Report is a comprehensive technical reference of water quality information for the citizens of Minneapolis. Electronic copies of the reports are available on the MPRB website, and can be found in the Caring for Our Parks - Lakes, Streams and Wetlands section. Hard copies of these reports are also available for check out at Minneapolis public libraries.
Lake Water Quality Monitoring Program
MPRB monitors Minneapolis lakes for water quality, using a database to track trends. Long-term monitoring is important because lakes can change from year to year, due to wet or dry weather. Analyzing years of data together must be done to see trends that will determine if the water quality is improving or not. These trends are also used to develop water quality goals and evaluate the effectiveness of Best Management Practices (BMPs).
The Minneapolis Lake Water Quality Monitoring Program began in 1991 as part of a study for the Chain of Lakes Clean Water Partnership, including Brownie, Calhoun, Cedar, Harriet and Isles. The monitoring program was expanded in 1992 to include Diamond, Hiawatha, Loring, Nokomis, Powderhorn, Webber and Wirth. Spring Lake was added in 1993.
Residents can help to monitor water quality also. For more information, see the River Watch program on the Hennepin County website.
Increased bacteria levels predominantly come from waterfowl and pet wastes in yards, streets and parks. This waste washes into our lakes, rivers and streams, either directly or through area storm drains, as the result of a heavy rain.
Minneapolis public beach water is monitored weekly throughout the summer, and is checked for bacteria that can be an indication of health risks for swimmers. Samples are collected and analyzed for indicator bacteria to determine if a health risk may be present for swimmers. If high bacteria levels are present, MPRB will close the beach until the water is safe for swimmers.
Best Management Practices (BMP) Monitoring
Grit chambers are constructed stormwater drainage system structures designed to remove sediment, trash and debris from storm runoff, so they are not deposited in receiving surface waters. Minneapolis Public Works first installed grit chambers in 1915, yet only seven were in place before 1990. Currently, Minneapolis maintains 145 grit chambers in our storm drain system. Please note that private grit chambers exist in Minneapolis, as well as units owned by Hennepin County and MnDOT.
Around the turn of the century, City engineers designed and constructed the first grit chambers. They were large underground concrete boxes with baffles, which allowed the water to slow down. Sediments and heavier materials then settled to the bottom of the chamber below the pipe entrance and exit. More recently, because of the greater demand for grit chambers, manufactured separator units that utilize modern technology to filter stormwater.
Minneapolis Public Works and MPRB together began grit chamber monitoring in 1998. Our goals include:
- Measure device effectiveness for specific units and site applications
- Determine optimal cleaning schedules (once the chamber is full, the device stops working, and material may also be washed out of the chamber)
- Develop better specification requirements and selection criteria for future installations, for both MPW, as well as being a requirement for private construction in Minneapolis
This project involves coordination of both water quality monitoring technicians and Minneapolis Sewer Operations personnel.
Additional Monitoring in Minneapolis
The following list shows other types of monitoring and water quality related data collection by MPRB:
- NPDES stormwater monitoring
- Watershed outlet monitoring programs
- Wetland health evaluations
- Stream bank erosion surveys
- Beach studies
- Lake levels
- Minnehaha creek levels
- Ice on/out dates
- Rain data
- Macrophyte (algae that is visible to the naked eye) surveys
- Macroinvertebrate (aquatic animals without backbones visible to the naked eye) surveys
- Winter dissolved oxygen monitoring
- Audubon certification monitoring
- Groundwater and drinking wells
- Irrigation and augmentation wells
There is additional monitoring that is performed by the four individual Watershed Management Organizations (WMOs) in Minneapolis. .
Last updated Nov 4, 2015