TMDL is a term that represents the total pollutant a water body can assimilate and still meet standards.
Since 1998, the Virginia Department of Environmental Quality (DEQ) has developed plans, with public input, to restore and maintain the water quality for impaired streams, lakes, and estuaries. These plans are called "Total Maximum Daily Loads," or TMDLs. Following EPA's approval of a TMDL, an Implementation Plan is developed.
Section 303(d) of the Clean Water Act and EPA's Water Quality Planning and Management Regulations (40 CFR Part 130) require states to develop Total Maximum Daily Loads (TMDLs) for water bodies which are exceeding water quality standards.
Waters that do not meet standards are reported to the citizens of Virginia and the US Environmental Protection Agency (EPA)
Below are links to information on the Accotink Creek TMDL's.
Accotink Creek/Long Branch Benthic TMDL 2014 - ?Managing Urban Stream Sedimentation Accotink Creek Case Study - An approach of infiltration first, stream restoration second, is recommended in a new Accotink Creek case study from the Vermont Law School - July 30, 2016
- - - - - - - - - - -TMDL Technical Advisory Committee meeting on July 28, 2016 - A quick summary. This is just my impressions. Page references are to the meeting presentation
Sediment TMDL: Based on their calculations, about 90% of the sediment in Accotink (page 9) comes from the streambanks (erosion, likely primarily from stormwater runoff). Returning Accotink to an "unimpaired" condition would require a sediment TMDL reduction of approx 70%! (page 14)
(Interestingly, Long Branch has a continuous turbidity data collector, so that should show sediment spikes associated with stormwater runoff.)
Chloride TMDL (salt): Accotink has issues with Chloride spikes (Page 18) (most likely from road salt runoff), that would require reductions of about 80% (page 25) to return to an unimpaired condition.
Representatives from DEQ, Fort Belvoir, Buckeye Terminals, Northern Virginia Regional Commission, Interstate Commission on the Potomac River Basin, Northern Virginia Community College, WSSI and VDOT attended.
There was some questioning of the methods used to interpret the data, and concern voiced about the impacts. DEQ has been pretty clear that they do not intend to do anything that will be seriously disruptive, and that their intention is for TMDL reductions to be a gradual, phased process.
From my perspective, this is a good process for FACC to be involved in. Based on my experience from the last TMDL process, at some point this will likely get a lot of attention/pushback. Road salt reduction will become a hot topic. - Kris Unger
- - - - - - - - - - -In 2014, the Virginia Department of Environmental Quality initiated a new Accotink Creek TMDL study to replace that voided by the 2012 lawsuit (see below). This new TMDL includes the Long Branch central tributary. In July 2015, the Stressor Analysis Report identified four most probable stressors: Chlorides (road salt), Sediment, Habitat Modification, and Hydromodification. Documents on the new TMDL:
Earlier Accotink TMDL's