Percentage of Surface Drinking Water from Intermittent,
Ephemeral, or Headwater Streams in New Hampshire
N
+
o
S Franklin
Claremont
Concord
I' .((ii (
Manchester
Legend: This map highlights regional patterns of dependence on
intermittent, ephemeral, and headwater streams for surface drinking
water in New Hampshire. In New Hampshire, 2,341 total miles of
streams provide water for surface water intakes supplying public
drinking water systems; of this, 1,311 miles, or 56%, are
intermittent, ephemeral, or headwater streams. Over 500,000 people
in New Hampshire 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.
Rochester
Portsmouth
Key:
Intermittent, ephemeral,
and headwater stream
miles as percentage of
total stream miles
contained in all SPAs
for a given county
49% - 56%
57% - 67%
I Nashua -
0
5
10
20
30
40

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