Percentage of Surface Drinking Water from Intermittent,
Ephemeral, or Headwater Streams in Wisconsin
Key:
Intermittent, ephemeral, and
headwater stream miles as
percentage of total stream
miles contained in all SPAs
for a given county
0.2% - 35%
99.51% -100%
No Data
Superior
Pembine
iiau Claire ]	
Appleton
Oshkosh
Sheboygan
Madison
Milwaukee
k Racine
I Kenosha
MlO^
Legend: This map highlights regional patterns of dependence on intermittent, ephemeral, and headwater streams for surface
drinking water in Wisconsin. In Wisconsin, 504 total miles of streams provide water for surface water intakes supplying public
drinking water systems; of this, 254 miles, or 50%, are intermittent, ephemeral, or headwater streams. Over 390,000 people in
Wisconsin receive drinking water from public drinking water systems that rely at least in part on intermittent, ephemeral, or
headwater streams. This analysis compared the stream length of intermittent, ephemeral, and headwater streams to total stream
length within all mapped Source Protection Areas (SPAs) for each county. A SPA is an area upstream from a drinking water source or
intake that contributes surface water flow to the drinking water intake during a 24-hour period. This is based on data that generally do
not include streams less than one mile in length. Intermittent streams are streams containing water for only part of the year.
Ephemeral streams flow in response to precipitation events. First-order streams have been used to represent headwater streams.
Data Sources: National Hydrography Dataset Plus at medium resolution; Federal Safe Drinking Water Information System 4th

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