2.4.7 Potential Environmental Hazards
While this section discusses some of the potential environmental hazards within the watershed, there are many more subtle potential hazards. Some of these include non-point source pollution, urban and agricultural runoff, as well as nutrients in surface water and groundwater.
Permitted Point Sources
In Minnesota, point source discharges of regulated pollutants are regulated under the National Pollutant Discharge Elimination System (NPDES) permit program. Figure 18 identifies permitted point sources in the watershed.
Landfills, Dumps, Storage Tanks, and Hazardous Waste Sites
Solid waste may contain harmful chemicals or toxic substances that have the potential to contaminate water resources. Hazardous waste and leaking above and below-ground tanks can be sources of both groundwater and surface water contamination. Hazardous waste generator and MPCA leak sites are shown in Figure 18, which locates known current and abandoned landfills, dumps, and hazardous waste sites in the watershed.
Feedlots have been defined by the MPCA “A lot or building or combination of lots and buildings intended for the confined feeding, breeding, raising, or holding of animals and specifically designed as a confinement area in which manure may accumulate. Or, where the concentration of animals is such that a vegetative cover cannot be maintained within the enclosure. Open lots used for the feeding and rearing of poultry (poultry ranges) shall be considered to be animal feedlots. Pastures shall not be considered animal feedlots.” (MPCA 1997). Because of the high density of animals and lack of vegetation common to feedlots, these areas can contaminate water resources with animal waste, sediment, and other pollutants.
Limited data is available on feedlots and other sources of animal waste in the watershed. Figure 19 shows the locations in the watershed of known feedlots, although the data for both counties is several years old. The Hennepin Conservation District in the 1990s compiled a windshield survey of feedlot and horse facilities. Figure 19 illustrates that data.
Groundwater connections can be a potential source of groundwater contamination. Known wells from the County Well Index are shown in Figure 20. Some of these wells may have been properly abandoned and sealed, but those still in operation and those abandoned but not sealed may provide a pathway for contamination of surficial or deeper aquifers.