DC Consolidated TMDL Implementation Plan

Tuesday, May 19, 2015 - 4:04pm

The Consolidated TMDL implementation Plan

Reducing Stormwater Runoff and Pollution in the District’s Waterways


Highly urbanized areas have lots of impervious surface. Parking lots, pavement, foundations and even compressed soil in fields prevent rain from infiltrating the soil the way Mother Nature intended.  Instead, we have to manage stormwater by directing the flow in order to avoid flooding.

The District of Columbia has two distinct storm systems, and both have drawbacks.  The infamous “combined sewer system” combines sewage and stormwater in the oldest parties of the city.  The civil-war era infrastructure combines sewage and stormwater into a single pipe, and directs it to our state-of-the-art sewage treatment facility.  The drawback comes when it rains – the pipes cant handle the combined flow and “overflows” dump the combined sewage – as many as 2.5 billion gallons each year – directly into the city’s rivers. 

The “newer” stormwater system is the Municipal Separate Stormwater System (MS4). MS4 storm drains take the water directly from surface streets to the river.  The water gets no filtration or treatment.  The good news is this means no raw sewage – the bad news is it picks up whatever contaminants are on the streets, parking lots and other places the water flows before it enters the train and delivers those contaminants unabated to the river.  

Every five years, the EPA, stakeholders and the district work together to come up with an “MS4 Permit” – a document that establishes limits on how many contaminants of concern can be allowed to enter our rivers via the MS4 system.  Certain individual contaminants are so prevalent in the Anacostia they are issued a daily cap – known as a Total Maximum Daily Load (TMDL).  A TMDL is the pollution diet – setting the bar that the District and Maryland should be below for each contaminant we are concerned about.

  pollutant baseline graph  

The District is in the midst of a major strategic planning effort to address stormwater pollution from the city’s MS4 drains. The result of this planning effort, the Consolidated TMDL Implementation Plan, will result in a performance-based approach for reducing stormwater runoff volume and pollution, while allowing the District flexibility to plan and allocate resources.  Over the last two years, Anacostia Riverkeeper and partners have been meeting with the District’s Consolidated TMDL planning team and contractors regarding the final plan.

The process saw the development of a new consolidated TMDL implementation plan that features an emphasis on green infrastructure and adaptive management.  The plan was based on a revised framework for monitoring, an analysis of the baseline (what we thought our starting point was vs. what it actually is), a scenario analysis, (plugging in different development, stormwater bmp tools, etc and projecting the changes over periods of time), a gap analysis (what we have in place, where we need to get and determining what’s missing) and some other tools to arrive at a plan to bring the District’s waterways up to water quality standards that can safely support fishing and swimming. 

This graph shows how far we have to come – pollutants are along the bottom, a “box” is a water segment that fails to achieve water quality standards. The dot in the box shows how much work there is to do.  An empty box or a box with a tiny dot is close.  A half-size blue dot is about 50% there.  A big, bright green dot has 100% of the way to go.  This mostly blue and green tells the story – we have a long way to to before we can achieve water quality standards for the Anacostia.

The Consolidated TMDL plan is now open for public comment.  It’s technical – but don’t worry!  It’s still helpful for the District to hear from you regarding the plan.  Please let the district know that you support the Anacostia, and want to see a TMDL plan that aggressively seeks reductions in major pollutants that make the Anacostia River unsafe for fishing and swimming.  Let the district government know that as a taxpayer and DC Water Rate payer, you feel the costly investment the District must make to achieve water quality standards is a worthwhile investment, and that a safe and healthy Anacostia River for future generations is a worthy investment.  Lastly, while modeling is a useful tool, please let the District know that there is no substitute for physical monitoring as a tool to measure performance.  The most robust monitoring program feasibile is the only way to know what stormwater management practices are yielding improvements and getting us closer to an Anacostia River safe for our kids and grandkids to splash about, catch and eat fish, and enjoy without considering the health impacts.   


The documents are available for review here:

Consolidated TMDL Implementation Plan

Revised Monitoring Program (Draft)

Comprehensive Baseline Analysis

Scenario Analysis


There are other documents, too, including meeting minutes, appendicies, and other resources, available at http://dcstormwaterplan.org/


Here’s how to comment:


This document is open for public comment for the next 2 months. Email Jonathan Champion (jonathan . champion @ dc . gov)  with “Consolidated TMDL Implementation Plan public comments” in the subject line, or mail your comments DDOE, Stormwater Management Division, 1200 First Street, NE, 5thFloor, Washington, DC  20002, Attention: TMDL Implementation Plan.