"TMDL"
Total Maximum Daily Load

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)
in the 303(d) Impaired Waters Report .

Below are links to information on the Accotink Creek TMDL's.
No Implementation Plans have been developed yet for Accotink Creek TMDLs!


Accotink Creek/Long Branch Benthic TMDL 2014 - ?

Final Public Meeting and Call for Comments, June 28, 2017:
I attended the DEQ Final Public Meeting last night for the Accotink Creek Sediment and Chloride TMDL Study to develop TMDL standards for the Accotink Watershed.

A public comment period will end on 21 July 2017, after which the final report will be prepared, unofficially forwarded to the EPA for their concurrence, and upon their unofficial acceptance, forwarded to the Virginia State Water Control Board for final approval before official submission to the EPA.

The State Water Control Board meets once per quarter and so, DEQ is hoping to gain acceptance at the December 2017 meeting, otherwise acceptance will have to wait until the March 2018 meeting. EPA should accept the TMDLs within a short time after receipt. So, EPA accepted TMDLs for the Accotink Creek may be in place by June 2018.

Permit holders, such as City of Fairfax, Fairfax County, City of Vienna, etc, will need to address the new TMDL standards as a part of their five year MS-4 permit applications.

The permit for Fairfax County expires 31 March 2020, therefore the county is not obligated to address the new standards until the next application submission. So I hope you understand my concern expressed a couple of board meetings ago regarding the Lake Accotink Park Master Plan schedule being hinged upon the plan DPWES develops.

The reality is that the county is already looking at the new standards - assuming their eventual acceptance - as is VDOT and the other jurisdictions, determining what actions they will need to take.

The other issue - that of retaining the Lake Accotink - is one that DEQ takes no official position on, but one in which the data show is a prudent thing to do from a water quality perspective as sediment readings from the Lower Accotink (below the lake), are healthier than those of the Upper Accotink (above the lake) and Long Branch Stream Valley, although all of them are well below the VSCI (Virginia Stream Condition Index) of 60 which is reflective of a healthy stream.
- Tony Vellucci - June 29, 2017

Read Friends of Accotink Creek written comments

More detailed information:

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The End of the Beginning?
In preparation for presentation of the TMDL plans at the final public meeting, the Technical Advisory Committee met on June 7, 2017. While the details of the draft TMDL's that were discussed in the meeting were beyond the technical capability of this reporter, a few non-technical points are relevant:
  • The TMDL's will be presented at a final public meeting June 28, 2017.
  • There are two separate TMDL's, one for sediment and one for chlorides (road salt).
  • Public comments are invited through July 21, 2017.
  • Following finalization of the TMDL's, there will be a period of review by the Virginia Water Control Board and by the EPA.
  • Following the review period, action will depend on the initiative of the various public & private local MS4 permit holders, likely not to happen until the next 5-year renewal is due for each permit.
  • Interesting fact - Lake Accotink is estimated to trap 47% of sediment arriving from upstream.
- June 17, 2017

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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

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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

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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