Percentage of Surface Drinking Water from Intermittent,
Ephemeral, and Headwater Streams in Connecticut
[ Hartford1
Torrington
Waterbury
New London
^^mbury
New Haven
Bridgeport
Norwalk
Stamford
0
4 8
16
24
32

Key:
Intermittent, ephemeral, and
headwater stream miles as
percentage of total stream
miles contained in all SPAs
for a given county
48% - 56%
57% - 69%
76%
No Data
Legend: This map highlights regional
patterns of dependence on intermittent,
ephemeral, and headwater streams for
surface drinking water in Connecticut. In
Connecticut, 1,432 total miles of streams
provide water for surface water intakes
supplying public drinking water systems; of
this, 845 miles, or 59%, are intermittent,
ephemeral, or headwater streams. Over 2.2
million people in Connecticut 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.
STA

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