The federal Clean Water Act requires states to submit a report every two years, assessing the condition of state waters based on data gathered. This report is the Dirty Waters List or the 305(b)/303(d) Water Quality Assessment Integrated Report as it is formally called.
The national listing is published online by the Environmental Protection Agency, identifying water bodies that are non-impaired, impaired, or not assessed. Impaired is a terminology given to streams, rivers, lakes, and estuaries that do not meet state water quality standards and do not support the public uses designated for the water bodies.
There are six designated uses that surface waters may support:
- aquatic life
- fish consumption
- public water supplies (where applicable)
- shellfish consumption
The standards define the level of water quality needed to support each of these uses. For example: A stream designated for swimming use has specific standards, if there is more contamination than what is allowed by those standards, then the stream is considered impaired for that designated use. A stream can have more than one designated use and only be impaired for one of the designated uses. Once added to the dirty waters list, a cleanup plan (called a “total maximum daily load”) must be developed and implemented to restore healthy use of the stream.
The 2012 Dirty Waters List assessed the condition of Virginia's waters based on data gathered from January 2005 to December 2010. Some of the key findings from the report as summarized by Virginia Water Central News Grouper
*Note that only 33% of Rivers and Streams
are monitored each cycle.
- Non-impaired waters made up 5,347 miles of rivers and streams, 19,638 acres of lakes and reservoirs, and 139 miles of estuaries.
- Impaired waters include 13,145 miles of rivers and streams (about 25% of the total in Virginia), 94,041 acres of lakes and reservoirs (about 81% percent of the total), and 2,129 square miles of estuaries (about 80% of the total).
- Additional impaired waterbodies listed compared to the 2010 report are 846 miles of streams and rivers, 100 acres of lakes, and 2 square miles of estuaries.
- Water bodies removed from the impaired list because they now fully meet the water quality standards include about 260 miles of rivers and streams and 2,700 lake acres. Another 230 miles of rivers and streams and 4,060 lake acres have been partially delisted because of improvements of an impairment for at least one designated use.
- Water bodies not assessed in the 2012 report include about 33,700 miles of rivers and streams, 2,700 acres of lakes and reservoirs, and 400 square miles of estuaries. Virginia monitors about one third of the state's watersheds every two years on a rotating basis.