Two segments of Goose Creek are impaired enough that water quality and some of the small aquatic life are affected, according to a state-required pollution analysis conducted by the Virginia Department of Environmental Quality (DEQ) and the Department of Conservation and Recreation (DCR).
The DEQ and DCR are developing what is called Total Maximum Daily Loads (TMDLs) for the two segments for violating the state’s water quality standards and the stream's designated uses for aquatic life. TMDL is the maximum amount of pollution a water body can assimilate and still meet water quality standards, which are set by the state and approved by the Environmental Protection Agency (EPA). The sources of pollution are identified in a TMDL study, including point sources from residential, municipal and industrial discharges and non-point sources from residential, urban and agricultural runoff.
"It's important to raise awareness in the watershed of the impacts different activities can have on the quality of streams," said Kate Bennett, regional TMDL coordinator for the Northern Virginia Region of the DEQ, referring to the 380-square-mile Goose Creek Watershed where the two stream segments are located.
Representatives from DEQ and DCR announced the beginning steps for developing a TMDL at a public meeting on April 10 that had a turnout of about 20 people.
THE 1972 CLEAN Water Act requires TMDLs to be developed for impaired waters, as handled by DEQ. The 1997 Water Quality Monitoring Information and Restoration Act requires implementation plans for the TMDLs. DCR acts as the lead on plan development for each impaired stream segment and pollutant in the state.
Every two years, the state submits a list of impaired streams and other water bodies to the EPA, the funding source for the TMDLs. In 2001, the state started the TMDL process in Loudoun County for four impaired segments in Catoctin Creek, all involving bacteria, and submitted the TMDL to the EPA in 2002. The state submitted a TMDL for Goose Creek, which had seven impaired segments caused by bacteria, to the EPA about two months ago.
The latest TMDLs are for a 4.91-mile segment of Goose Creek from Goose Creek Damn downstream to the confluence with the Potomac River and 6.13 miles of Little River from Hungry Run near Route 50 downstream to the confluence with Goose Creek. The segments are unable to support aquatic life as determined by a biological assessment of the benthic community of macro-invertebrates, which live in the bottom of streams and other water bodies. The health of macro-invertebrates indicates the level at which a stream can support the state's aquatic life use goal, or a balanced indigenous population of aquatic life.
"These organisms can be stressed but the water may not be so polluted we can't drink it," said Mike Shelor, aquatic ecologist for DCR.
AFTER IDENTIFYING the benthic impairments, the state conducted a more in-depth investigation to identify the cause of the impairment, which is called the stressor, and the reductions necessary to restore the benthic community.
"Goose Creek and Little River have excess sediment," said Ross Mandel of the Interstate Commission on the Potomac River Basin. "Our preliminary conclusion is sediments and nutrients are the cause of the impairment."
If the two stressors are the cause, the state will develop TMDLs for the nutrients and sediment in the two stream segments. Mandel said by the end of the month he expects to finish identifying the stressors.
The DEQ and DCR will accept written comments on the TMDLs until May 9. A second public meeting will be held in October to present the draft TMDLs. The final TMDLs will be submitted to the EPA a month later for final approval. If approved, DCR will develop an implementation plan to bring the impaired segments into compliance with the state's water quality standards.
DEQ led in developing the TMDL, while DCR will be responsible for implementing the plan by working with stakeholders to get the TMDL in place and by identifying funding sources.
"We're hoping we can get everyone in the watershed to participate and cooperate and buy into what we're doing," Bennett said. "It's important to have our streams support the designated uses we give them."
Two additional TMDL studies are planned for bacteria impairments in Limestone Branch in eastern Loudoun and in Piney Run in northwestern Loudoun.
So far, EPA has approved 51 TMDLs in the state. EPA and the state are required to complete 636 TMDLs by 2010 under the 1999 Consent Decree.