Percentage of Surface Drinking Water from Intermittent,
Ephemeral, and Headwater Streams in Michigan

N
+
Grand Rapids
Lansing
Warren
Detroit
Ann Arbor
Key:
Intermittent, ephemeral, and
headwater stream miles as
percentage of total stream
miles contained in all SPAs
for a given county
0%
0.08% - 44%
I	I 45% - 56%
56% - 69%
| 69% - 78%
No Data
dS sri;
%pR0^
0
15
30
60
90
120

Legend: This map highlights regional patterns of dependence on intermittent, ephemeral, and headwater streams for surface drinking water in
Michigan. In Michigan, 1,342 total miles of streams provide water for surface water intakes supplying public drinking water systems; of this, 551
miles, or 41%, are intermittent, ephemeral, or headwater streams. Over 1.4 million people in Michigan 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 4,hQuarter 2006 Data.

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