Potential sources of bacteria and actions to address
Link to this table

General Category Source Action
Municipal Sanitary Infrastructure Combined Sewer Overflows1 Replace infrastructure, if possible
Sanitary Sewer Bypasses/Overflows Line sanitary sewer pipes
Inflow and Infiltration Minimize and eliminate through repairing damaged sewers
Illicit discharges from unsewered communities Detect and eliminate illicit discharges
Human Sanitary Sources Leaky/failing septic systems Update and enforce subsurface sewage treatment system (SSTS) ordinances
Educate homeowners on septic system maintenance and opportunities for replacement
Implement higher standards for setbacks for installing septic systems near receiving water bodies
Porta-potties Ensure construction site temporary toilets have appropriate pollution prevention BMPs
Domestic pets Dogs, cats, dog parks, walking trails, residential yard and sidewalk runoff (spring runoff after winter accumulation) Establish pet waste disposal stations along trails, in dog parks, etc.
Pass and enforce pet waste ordinances and educate pet owners about them
Add infiltration BMPs downstream of parks/residential areas and upstream of stormwater pipes (i.e., somewhere between the park/residential area and the stormwater outfall so as to intercept and infiltrate some or all of the flow from these areas)
Reduce transport from parks, residential, and other areas by the use of buffer zones and other disconnection of flow pathways (e.g. impervious surface, disconnection, downspout disconnection)
Urban wildlife Rodents (raccoons, squirrels, etc.), deer, etc., birds (geese, ducks, swallows, etc.), areas where wildlife congregate such as fields, parks, and golf courses Wildlife feeding bans and control of nuisance populations, including ducks and geese and other wildlife
Remove community facilities such as vending machines for feeding ducks and geese
Add buffers in riparian zones near waterbodies to deter waterfowl congregation
Consider wildlife barriers if wildlife (e.g. raccoons) are found to be living in storm sewers
When possible, use infiltration BMPs instead of detention ponds in residential developments and other areas where wildlife may congregate
Other Urban Sources (non-stormwater) Excessive irrigation/overspray Assess the extent to which irrigation over-spray occurs at city-owned facilities and eliminate overspray as appropriate
Education on water conservation
MS4 Infrastructure Illicit sanitary connections to MS4 Detect and eliminate illicit discharges
Leaky sewer pipes Line sewer pipes
Biofilms/regrowth Reduce dry weather flows, which provide conditions that promote bacteria growth. Dry weather flows could be from night time irrigation of lawns/parks or leaky stormsewer pipes.
Decaying plant matter, litter, and sediment in the storm drain system Enhance street sweeping program.
Prevent the discharge of grit chamber clean out effluent
Remove leaf litter and soil in street and gutters: implement an Adopt-a-storm drain program
Other Natural Sources Stream Bank Erosion Streambank restoration

1Note only a few combined sewers remain in Minneapolis
*This table was created using information from the Upper Mississippi River Bacteria TMDL Study (2014) and Protection Plan and the Upper Mississippi River Bacteria TMDL Implementation Plan (2016), Pathogens in Urban Stormwater Systems (2014), and the Minnehaha Creek Bacterial Source Identification Study (2017).

This page was last edited on 11 May 2020, at 13:35.

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