Percentage of Surface Drinking Water from Intermittent,
Ephemeral, and Headwater Streams in Missouri
Legend: This map highlights
regional patterns of dependence
on intermittent, ephemeral, and
headwater streams for surface
drinking water in Missouri. In
Missouri, 10,115 total miles of
streams provide water for surface
water intakes supplying public
drinking water systems; of this,
6,311 miles, or 62%, are
intermittent, ephemeral, or
headwater streams. Over 2.4
million people in Missouri 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.