Jan 29, 2009

National Water Quality Inventory Report Now Available Online

Information available on national and state levels

This report, available at www.epa.gov/owow/305b/2004report/, summarizes water quality assessments submitted by the states to the U.S. Environmental Protection Agency (EPA) under section 305(b) of the Clean Water Act.

The report finds that the states assessed 16% of the nation’s 3.5 million river and stream miles, 39% of its 41.7 million acres of lakes, ponds and reservoirs, and 29% of its 87,791 estuary square miles.

Forty-four percent of assessed river and stream miles, 64% of assessed lake acres, and 30% of assessed estuary square miles were found to be impaired for one or more of the uses designated for them by the states.

Leading causes of impairment included pathogens, mercury, nutrients, and organic enrichment/low dissolved oxygen. Top sources of impairment included atmospheric deposition, agriculture, hydrologic modifications, and unknown or unspecified sources.

This report is a companion to electronically submitted state water quality information available on the EPA’s website, known as ATTAINS, at www.epa.gov/waters/ir.

In addition to viewing the national summary and information by state at this website, users can click down to the individual water body level to find out more about water quality conditions.