Source Water Assessment Area - Surface Water

These areas were delineated in 2002 and 2003. The source water assessment area for community public water supply systems using surface water intakes includes three distinct nested areas. The inner emergency response area is designed to help the city address contaminant releases which present an immediate (acute) health concern to water users. This geographic area is defined by the amount of notification time the city needs to close the surface intake and a "buffer time" to accommodate unanticipated delays in notification and shut down. The outer source water management area is designed to enable protection of water users from long-term (chronic) health effects related to low levels of chemical contamination or the periodic presence of contaminants at low levels in the surface water used by the city. This area is intended to enable protection of users from contaminants that may 1) be usually present at treatable levels in the source water and 2) occasionally present an acute health concern under certain conditions, such as periods of high runoff or storm events. The establishment of this area also recognizes the potential for future land-use development that may influence source water. The third assessment area is the entire watershed in Minnesota. This area is designated to provide the water supplier with a broad perspective in which to prioritize specific types of land uses that may impact the water quality of the source water used. U.S. Environmental Protection Agency guidelines suggest including the entire watershed up to the state boundaries as part of the source water assessment area. Altogether, these three areas are collectively labeled the "source water assessment area." The entire watershed area is currently not included in the GIS dataset. Non-community source water assessment areas for surface water are also not included. Burnsville currently has a surface water intake but did not during the time period this dataset was created. Beaver Bay and Silver Bay do not have an inner emergency response area and share an outer source water management area. These will be replaced by new generation assessment areas in the near future.