^Wilmington
Newark
|Dove^
Milford
Percentage of Surface Drinking Water from Intermittent,
Ephemeral, and Headwater Streams in Delaware
Legend: This map highlights regional patterns of
dependence on intermittent, ephemeral, and headwater-
streams for surface drinking water in Delaware. In
Delaware, 344 total miles of streams provide water for
surface water intakes supplying public drinking water-
systems; of this, 184 miles, or 53%, are intermittent,
ephemeral, or headwater streams. Over 280,000 people in
Delaware 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 Quarter 2006 Data.
*L PRO"**-
Key:
Intermittent, ephemeral, and
headwater stream miles as
percentage of total stream
miles contained in all SPAs
for a given county
53%
No Data
28
3 Miles

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