Chesapeake Bay TMDL
Regional Food System
Land Use &
Browns, Craig &
Carter, Deep, Great
& Thumb Runs
Hazel, Hughes &
Robinson River &
Little Dark Run
The Rappahannock-Rapidan Regional Commission, on behalf
of the Virginia Department of Environmental Quality, and in conjunction
with Engineering Concepts, Inc., has recently completed development of
a series of 16 TMDLs located in the Upper Rappahannock
Waters by County (August 2008): This is a Microsoft Excel spreadsheet
listing all impaired waters in the Rappahannock-Rapidan region by county,
year and impairment type.
What is a TMDL?
A TMDL, or Total Maximum Daily Load, is a term used to describe
the amount of pollution a stream can receive and still meet Water Quality
Standards. Water Quality Standards are regulations based on federal or
state law that set numeric or narrative limits on pollutants. TMDLs are
required for waterbodies that have been determined to be impaired. The
Virginia TMDL program is governed by a federal court order Consent Decree
which lays out a schedule for TMDL Development through 2010.
What is the purpose of a TMDL Study?
A TMDL study identifies sources of pollution and reductions needed to
attain water quality standards. A TMDL considers point sources
such as residential, municipal, or Industrial discharges and non-point
sources such as residential, urban, or agricultural runoff. Virginia’s
goal is that all streams attain the applicable beneficial use(s) for which
they have been designated, e.g., drinking water, swimming, fishing, shell-fishing,
and aquatic life use. These are protected by application of the state’s
water quality standards.
How does Virginia determine what is an Impaired Water?
Through water quality monitoring and assessment (i.e., comparing the monitoring
data to the applicable water quality standards), the Virginia
Department of Environmental Quality (DEQ) determines whether
a waterbody is impaired or not. Every even numbered year, Virginia submits
a list of the waters found to be impaired, referred to as the 303(d) list,
to the Environmental Protection Agency. Currently, 636 waters have been
determined to be impaired across the state.
- from Frequently Asked Questions About. . . TMDL Development, Virginia
Department of Environmental Quality, March 2002, by J. Schneider.
Additional information on TMDLs can be found on
the DEQ website located at:
TMDL Information from Virginia DEQ