By Sean Tubbs
Saturday, January 8, 2011
The Virginia Department of Environmental Quality has begun a planning process to clean up watersheds that feed four streams within Charlottesville’s city limits.
The health of a waterway is gauged by a metric called the composite stream index. A stream with a score higher than 60 is considered healthy, but none of Charlottesville’s streams comes even close. That means that no swimming or fishing is allowed in any of Charlottesville’s streams.
“It’s not a huge surprise to many of us that some of our local waterways, including Meadow Creek, Schenks Branch, Moores Creek and Lodge Creek don’t meet water quality standards,” said Kristel Riddervold, the city’s environmental administrator.
The local cleanup process, which began with a public meeting Thursday, mirrors and complements an ongoing process by which the federal, state and local governments are attempting to clean up the Chesapeake Bay watershed.
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In both cases, a pollution diet is being drafted that will put a total maximum daily load (TMDL) on pollutants that can enter the waterway before it can be classified as impaired.
“A TMDL has two meanings,” said Tara Dieber with DEQ. “One, it’s the exact quantifiable amount of pollution that a stream can take in and still maintain water quality standards. But it’s also the process of … going about identifying that amount.”
The local TMDL will focus on reducing bacteria and sediment, whereas the bay TMDL also seeks to reduce levels of nitrogen and phosphorous. The DEQ and a volunteer advisory group will take the next six months to evaluate conditions in each stream’s watershed before a cleanup plan is written later this year.
“That’s where we get into the detail and the nuts and bolts of how we’re going to clean this up,” Sieber said. “What exact practices can we put into place to make sure that this pollutant is reduced from these sources.”
Sieber said a large reason for decreased water quality is impervious surface, which reduces the ground’s ability to absorb rain. Instead, rainwater accelerates, increasing the likelihood sediment will be carried into streams. For instance, 36.2 percent of land in the Schenks Branch watershed is covered with impervious surfaces.
Sediment presents a problem for aquatic life because the smaller particles of soil fill in around gravel and pebbles that provide a place for creatures to live.
“When there’s too much sediment, the bugs aren’t able to have a good community. It’s like living in a house full of junk,” Sieber said. Poor aquatic life leads to a less healthy food chain.
Impervious surfaces can be mitigated in a variety of ways, including by planting trees along streambanks to serve as buffers to filter out water. Tree roots help prevent sediment from entering streams.
The city is restoring the banks of the Meadow Creek, and the city, Albemarle County and Rivanna Water & Sewer Authority are all working to tighten up and expand sewer pipes to prevent leakage and provide additional capacity.
Another reason water quality has deteriorated is erosion caused by stormwater systems. Riddervold said changing long-held practices could go a long way to restoring streams.
“The mindset was, ‘Let’s get the water out of here as fast as possible and as quick as possible and send it through a chute,’” Riddervold said.
While the DEQ and local officials work on a TMDL for Charlottesville, groups are working concurrently on action steps to comply with the Chesapeake Bay TMDL.
“The cleanup plan that’s happening locally is coming in right at the time when Charlottesville is going to be dealing also with its target loads because of the bay TMDL,” said Leslie Middleton, the executive director of the Rivanna River Basin Commission. “Everything we do to clean up these local streams is going to help with the bay cleanup plan. Charlottesville will get credit for activities that clean up the streams.”
Written comments on the local TMDL can be submitted to the DEQ by Feb. 7. A second public meeting will be held in the summer as the written plan begins to take shape.
Sieber said it is unlikely any additional money will come from the state to help pay for implementation of the local plan. However, she said having a written plan would help the community obtain grants to help pay for mitigation projects.