#62 The Rivanna TMDL is Underway

The Rivanna at Darden Towe Park in another season and another year
Credit: Stowe Keller

October 11, 2007


The autumn sunlight warms the group gathered around the table. The air is collegial and cooperative: the Virginia Department of Environmental Quality’s TMDL Coordinator has come with three consultants from the Lois Berger Group, specialists in the process. They’ve set up a poster presentation on an easel to one side that summarizes the Rivanna TMDL meeting in March with colorful charts and lists.

This is the first time I’ve been able to participate since the meetings commenced in November last year. I’ve got a ways to go to catch up with the water professionals who help make up the Steering Committee, folks from non-profits and local agencies and government who provide the knowledge of our watershed that is essential for development of a TMDL.

This acronym stands for Total Daily Maximum Load – and simply put, refers to the total amount – or load – of a given pollutant that a water body can receive in a day and still meet water quality standards. If you hear that a stream or river has a TMDL, it means that it has degraded to the point that it no longer meets state standards and has been placed on the impaired waters list.

Making this list is a dubious distinction. The good news is that once a river stretch has been listed as impaired, it becomes eligible for funding that will study the problem, determine the sources of the pollutant, and help identify solutions.

Fifteen stream and river segments in the Rivanna watershed are listed as ‘impaired” because they do not adequately support the biological organisms that reflect a healthy stream or are excessively contaminated with bacteria that is unhealthy for humans. Sixty-two miles in Albemarle County alone are impaired for these bacteria that make swimming, canoeing and simply wading in the river with your kids a cause for extra caution and some disinfectant.

And where are these streams? For bacterial impairment we’re talking about the headwaters of Beaver Creek above the reservoir; the entire length of Meadow Creek; almost 26 miles of Preddy Creek and its tributaries; 10 and half miles of the Mechums River from Lickinghole Creek to its confluence with the Moormans; the North Fork from Camelot to the main stem and continuing down to Moores Creek.

The TMDL process starts with identifying the likely sources, such as failing septic systems, straight pipes, and wastes from pets, livestock, and manure spreading operations. Information is fed into a computational model along with climate, stream flow, and geographic data specific to our watershed. At the end of this year, DEQ will define what the total amount of bacterial pollutant these stream segments can absorb and still maintain adequate water quality for safe recreation.

The target number and sources are open for public comment, then approved by the state and EPA, and will be used to inform and plan clean-up efforts during the next phase called implementation planning. Activities to eliminate the sources are prioritized – in this case, things like eliminating failing septic tanks, initiating pet waste education campaigns, or ensuring adequate stream buffers on all the streams in the watershed. The TMDL process can take years and is highly dependent on state funding to complete. And finally we come to the bad news: all the while, unless the community takes corrective measures voluntarily, the pollution from these sources may continue.

So while the consultants are crunching the numbers, our local water quality experts will continue the real work of trying to influence patterns of land use and encourage living habits that we can adopt now. The TMDL process comes up with a number and a plan – but there’s every reason we should take it upon ourselves to clean up after our pets, keep our cattle out of the streams, and limit the amount of soil that turns our river the color of Virginia clay.