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Literature Survey on BMP Reduction Efficiencies for Pathogens and Indicator Bacteria

ICPRB was interested in exploring methods for developing implementation plans which address TMDLs for multiple constituents.  In particular, ICPRB was interested in documenting how methods to control nutrient and sediment can be related to bacteria controls and how management actions required to meet the nutrient and sediment reductions under the Chesapeake Bay TMDL may have benefits for reducing bacteria to meet the goals of local bacteria TMDLs. This interest is an outgrowth of earlier work ICPRB performed for the DC Source Water Assessment, where the Phase 4 Watershed Model was adapted to simulate fecal coliform bacteria so that likely sources of pathogens at DC water intakes could be identified.

After initial research, it was found that a survey and report had already been completed for urban Best Management Practices (BMPs) . The associated database, known as the International Stormwater BMP Database, is available online. A literature survey of bacteria efficiencies for BMPs in the Phase II Watershed Implementation Plans (WIPs) had also been performed as part of an effort to quantify additional benefits from the implementation of the Chesapeake Bay TMDL. This findings report documents the key elements in the urban BMP database and the more general survey quantifying the additional benefits from BMP implementation.

The findings of these two reports are documented below.

International Stormwater Best Management Practices Database

The International Stormwater Best Management Practices Database was developed by Wright Water Engineer and Geosyntec Consultants on behalf of the American Society of Civil Engineers, the U. S. Environmental Protection Agency, the Water Environment Research Foundation, the Federal Highway Administration, and the American Public Works Association.  As of 2010, the BMP Database contained 2,500 analysis results for indicator bacteria from 141 studies. Most of the results were for fecal coliform bacteria.  Bacteria reduction efficiencies were documented for the following BMPs:

Grass Strips Green Roofs
Grass Swales Infiltration Trenches
Bioretention Porous Pavement
Dry Detention Basins Wet Retention Ponds
Sand Filters (or filters with other media) Artificial Wetlands

A parallel effort to develop a database for agricultural BMPs is underway but it does not appear that the effects of agricultural BMPs on indicator bacteria will be addressed by the database.

Additional beneficial outcomes of implementing the Chesapeake Bay TMDL: Quantification and description of ecosystem services not monetized

As part of a study for the EPA to estimate additional benefits derived from Chesapeake Bay TMDL implementation, Wainger et al. quantified the amount of bacteria reduction associated with implementation of the Phase II WIPs.   As part of that effort, Wainiger et al. performed a literature review of reported BMP efficiencies for reducing pathogens or associated indicator bacteria.  The review was conducted using Google Scholar, EBSCO, and Google. Efficiencies were taken from three sources: peer-reviewed journal articles, TMDL documentation from state agencies, and BMP guidance reports from state agencies and research universities. Appendix A of their report summarizes the bacteria reduction efficiencies found for the BMPs used in the state WIPs.  The report relied heavily on the International Stormwater BMP Database for efficiencies for urban BMPs.  Efficiencies for agricultural BMPs were derived to a large extent on guidance documents or TMDLs from Texas[1], Minnesota[2], and Virginia[3].  Bacteria reduction efficiencies for the following non-urban BMPs were determined through the literature review:

Barnyard Runoff Control Pasture Management
Land Retirement Loafing Lot Management
Pasture Alternative Watering Precision Grazing
Stream Access Control (Fencing) Livestock and Poultry Waste Management Systems
Forest Buffers Grass Buffers

Please contact us for more information.


[1]Peterson, J., E. Jordan, K. Wagner, and L. Redmon. 2012b. Lone Star Healthy Streams: Dairy Cattle Manual. Page 80. Department of Soil and Crop Sciences and AgriLife Communications, The Texas A&M System. Retrieved online.

Peterson, J., L. Redmon, and McFarland, Michael. 2011a. Reducing Bacteria with Best Management Practices for Livestock: Prescribed Grazing. Page 2. Texas AgriLife Extension Service. Retrieved online.

Peterson, J., L. Redmon, and McFarland, Michael. 2011b. Reducing Bacteria with Best Management Practices for Livestock: Access Control. Page 2. Texas AgriLife Extension Service. Retrieved online.

[2]MPCA. 2009. Groundhouse River Fecal Coliform and Biota (Sediment) Total Maximum Daily Load Implementation Plan. Page 61. Minnesota Pollution Control Agency. Retrieved online.

[3]VDEQ. 2003. Total Maximum Daily Load Development for Linville Creek: Bacteria and General Standard (Benthic) Impairments. Page 160. Virginia Department of Environmental Quality. Retrieved online.

Wainger, L. , J. Richkus, and M. Barber. 2015. Additional beneficial outcomes of implementing the Chesapeake Bay TMDL: Quantification and description of ecosystem services not monetized. Oneida Total Integrated Enterprises, LLC: Oak Ridge, TN. Retrieved online.

A wide-angle view of a lake with a forested bank in the background. Two men are fishing from a boat on the lefthand side.

Drought Exercise Completed

The region’s major water suppliers and the Interstate Commission on the Potomac River Basin Section for Cooperative Water Supply Operations on the Potomac (CO-OP) exercised their ability to respond to severe drought conditions during a week-long exercise beginning September 23, 2015.

CO-OP’s annual drought exercises are a way to practice operations under severe drought conditions. Under such conditions, the region’s normally independent water suppliers work cooperatively with CO-OP to meet the demands of their customers while minimizing the need for restrictions. The week-long exercise uses simulated low flows that allow all parties to practice daily reporting procedures, internal communications, and releases of stored water.

The three major water suppliers draw the bulk of their raw water from the Potomac River. A record drought could drop the natural flow of the river to a level insufficient to meet summertime water demands. When river flow and other data indicate a coming shortage, CO-OP can guide Potomac use among the suppliers and manage releases of stored water to augment flow in the river. The Jennings Randolph Reservoir on the North Branch Potomac holds billions of gallons of water that can be released to help meet Washington metropolitan area demands and environmental flow needs. A release from Jennings Randolph Reservoir can take 8-9 days to reach the metropolitan suppliers’ intakes. The much smaller Little Seneca Reservoir in Montgomery County, Md., is used to adjust river flow over a shorter period of 1- to 2-days.

This year’s exercise focused on honing the communications channels between the utilities, CO-OP, and the U.S. Army Corps of Engineers, divisions of which operate both as a metropolitan water supplier and operator of Jennings Randolph Reservoir. Another focus was the modeling that incorporates drinking water demand data and forecasts from utilities, stream flow data, and weather forecasts to determine the timing and volume of reservoir releases. In addition, the exercise included an actual release of water from Little Seneca Reservoir, testing improved data reporting systems, and a simulation of planned reservoir maintenance that could impact drought operations.

Drought response procedures are refined during the annual exercise, and have resulted in a resilient drinking water system for the Washington metropolitan area’s more than four-million residents who rely on the Potomac as their primary drinking source. More information about the metropolitan water supply system and CO-OP are available on the ICPRB website.

Contact us for more information on the exercise.

The ICPRB is celebrating 75 years of service to the Potomac basin and its residents.

Photo of a tree-lined river form the river bank.

FAQ on the Upper Potomac Spill

Below are some of the most frequently asked questions ICPRB has received regarding the September 23, 2015, spill in Luke, Md. If you have additional questions, please feel free to contact us. We will continue to update this page as more information is available.

Where did the spill occur and how much was spilled?

A valve in a tank that holds a synthetic latex-like chemical used to coat paper at the Verso paper mill in Luke, Md., was accidentally left open. The tank was being filled from a rail car, and the contaminant flowed into a containment area, then flowed to the wastewater treatment plant in Westernport, Md. About 10,000 gallons of the material went through treatment and into the North Branch Potomac River.

Is the contaminant toxic?

The latex is not considered a toxic substance. However, water utilities remain vigilant regarding the safety of their equipment and effects on river ecology. To date, no fish kills or other damage has been observed, and the treatment plant that the spill ran through before entering the river reported no damage to the bacterial colonies used in the treatment process.

How are the water utilities responding?

The ICPRB is working with drinking water utilities along the Potomac to keep them informed. A series of conference calls has allowed officials to communicate with each other and get briefed on the latest news. They were given estimates of the times when the contaminant plume will arrive at their intake, the peak concentration, and when the plume will be past the intake. Some of the utilities have stored water and will close their intakes until the contaminant has passed. Others further downstream have time to decide whether to close their intake, and are using this time to gather information on whether the contaminant could damage the treatment plant. Please contact your local water utility company with additional questions.

When is it expected to reach my area?

As part of ICPRB’s spill response protocol, the Emergency River Spill Model is continuously utilized to predict the travel time of the pollutant down the river. A limitation of the model is that it uses a single flow level to estimate travel time. The river is always dynamic, but especially so because of a recent upstream reservoir release and heavy rains in the watershed. The travel times are an approximation used to show utilities when they should start monitoring for the contaminant and when it will likely pass their intake. As of September 30, the contaminant plume is close to Hagerstown, Md., and will likely reach the metropolitan area water intakes on October 3. The ICPRB continues to run the Toxic Spill Model to help guide the utilities’ management decisions.

Will I have a reaction to the water if I am allergic to latex?

Although the coating substance is called “latex,” it is a synthetic compound and is not expected to affect people allergic to latex or other rubber products.

Can I still kayak/SUP/fish?

Based on current information, the substance is not harmful, but has discolored the water upstream. With the heavy rainfall predicted for the next few days, it is probably a good idea to stay off the water anyway until the contaminant passes. All this rain is quickly diluting the contaminant, and model runs predict a concentration of less than 1 part-per-million when it reaches the northern metropolitan area.

I am on a well. Will it affect my water supply?

No. There is no indication that the contaminant has entered the groundwater.

What do I do if I see a spill?

If you suspect a contaminant spill has occurred, please notify ICPRB and the appropriate agency. You can find our contact information and a list of agencies on our Spill Response page.

The red circle on the Google map above indicates the spot where the contaminant entered the river.

Looking to stay informed of spills in the Potomac River basin? Sign up for our Newsletter and follow us on Facebook and Twitter to get the updates!


Photo Credit: Jack Delawder, Paw Paw Water Plant

Photo of a muddy-looking river from the top of a bridge.

ICPRB Tracks Latex Spill for Water Utilities

The ICPRB is using an emergency spill model that can help water utilities in dealing with a spill of synthetic latex that entered the North Branch Potomac at Westernport, Md., on September 23, 2015.

The spill of synthetic latex occurred when a rail car of the substance was being unloaded at the Verso paper mill in Luke, Md. About 10,000 gallons spilled into a containment area and traveled to the Upper Potomac River Commission wastewater treatment plant in Westernport, Md., and was discharged to the North Branch Potomac. The Maryland Department of the Environment is investigating the spill, and is awaiting lab results of samples taken from the river. The agency noted that the latex substance, used to coat paper, is not expected to threaten public water supplies at this time.

The ICPRB Emergency River Spill Model provides more than a dozen downstream water intakes with estimates of the time of arrival, maximum contaminant concentration, and the time the contaminant is expected to be past the intake. The model results can be used to guide management decisions by drinking water utilities to protect public drinking water supplies, such as storing water and shutting intakes until the contaminant has passed.

Releases of water from reservoirs (such as a release from the Savage Reservoir last weekend) and rainfall can alter the results as the model uses a set value for river flow. The ICPRB spill staff has now produced multiple model runs covering a range of flow conditions, which have been passed along to the water utilities.  The contaminant may take days or weeks to reach the Washington metropolitan area water intakes, depending on the amount of rainfall during the next few days. The staff at ICPRB will continue to update this information to provide drinking water utilities with the best information available to guide protection of the resource. Visit this page to learn more about how ICPRB addresses toxic spills in the Potomac River basin.

**Updated 10/1/2015**

The ICPRB continues to run the Toxic Spill Model and coordinate with water utilities. The most recent run of the Toxic Spill Model (on September 30), indicates the plume will likely reach the DC metropolitan area on or around October 4, 2015, and will have a concentration of less than 1 part per million at that time. Based on sampling results from MDE, styrene and other VOCs are not being detected in the plume.

According to the Maryland Department of the Environment, the synthetic latex is not considered a toxic substance. Water utilities are being vigilant for possible damage to water treatment facilities, but none are expected at this time.  No fish kills are expected and none have been reported.

Please see our FAQ on the Upper Potomac Spill page for more information.

**Updated 10/2/2015**

The ICPRB ran it’s final Toxic Spill Model on October 1, 2015 and does not plan on providing any further travel time updates. The plume is expected to arrive in the DC metropolitan area on October 4-5, 2015, at a concentration of less than 0.05 parts per million. Due to recent heavy rains, an increase in river flow has moved the plume quickly down the river and has helped dilute the contaminant.

The Washington Aqueduct reports that tests of water samples collected in the contaminant plume indicated that the contaminants are readily removed by conventional treatment and do not contain detectable volatile organic compounds (VOCs).

The Maryland Department of the Environment has provided a summary of the spill and their sampling results. According to MDE, this is not considered a health concern.

The red circle on the Google map above indicates the spot where the contaminant entered the river.

Looking to stay informed of spills in the Potomac River basin? Sign up for our Newsletter and follow us on Facebook and Twitter to get the updates!


Photo Credit: Jack Delawder, Paw Paw Water Plant

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Apply today! ICPRB seeks Communications Specialist

Support the communications/outreach program of a multi-state water resources agency. Major responsibility for production and maintenance of website content (using WordPress) and related social media and news story development; develop education and outreach materials; assist technical staff with report production, respond to information requests.

B.A. in journalism/communications or related degree or 2 years related experience. Some experience in writing, web site maintenance, and public outreach. Familiarity with water, environment issues preferred.

Send cover letter, resume, salary history, and two writing samples to info@icprb.org or mail to Interstate Commission on the Potomac River Basin, Communications Specialist Position, 30 West Gude Drive, Suite 450, Rockville, MD 20850. Good benefits package. EEO.  Please respond by May 22. No phone calls, please.

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What is ICPRB doing for the Chesapeake Bay restoration?

ICPRB works with federal, state, and local partners to help achieve many of the goals and outcomes described in the 2014 Chesapeake Bay Agreement. Organized by the Outcomes listed in the Agreement, ICPRB’s activities include:
  • Forage Fish and Fish Passage Outcomes. For 20 years, ICPRB has been actively engaged in the restoration of American shad in the Potomac River and other Chesapeake tributaries and the Potomac and Rappahannock rivers have achieved their Atlantic States Marine Fisheries Commission population targets. ICPRB is advising the states on shad restoration in other tributaries and is a member of Bay Program workgroups for these outcomes.
  • Stream Health Outcome. ICPRB is developing one of the principal measures that the Chesapeake Bay Program (CBP) will use to measure stream health for this outcome.
  • 2017 and 2025 Watershed Implementation Plans Outcomes. ICPRB is part of the team developing the Phase 6 Chesapeake Bay Model, which is the key tool that will be used to assign pollutant load allocations to different land types and jurisdictions and to track progress in meeting pollution reduction goals.
  • Water Quality Standards Attainment and Monitoring Outcome. ICPRB is involved in building and maintaining the monitoring databases at the CBP and uses its expertise to analyze those data to determine status and trends of water quality and living resources parameters.
  • Citizen Stewardship, Local Leadership, Student Environmental Literacy, and Sustainable Schools, Outcomes. ICPRB runs several workshop and training programs for teachers and students. These include:
    • Watershed Connections workshops for teachers, where groups of teachers build table-top watershed models using common materials. The models are then used by students to explore how changes in land use affect water quality, soil erosion, and the spread of contaminants, and how best management practices can address problems.
    • Assessments of school grounds so that students and teachers can improve their schools through installation of appropriate best management practices. The assessment is performed in a classroom setting.
    • Stream Monitoring/Ecology programs. Outreach to schools to help them assess their local stream. This pilot project will result in monthly lesson plans that can be used by teachers in subsequent years.
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What does ICPRB do to address toxic spill threats?

On February 16, a train including tank cars carrying crude oil derailed with some of the cars dropping into the Kanawha River in West Virginia. Although not in the Potomac basin, this event is a reminder that accidental spills of toxic materials are an ever present risk to human health and the environment. Of particular concern are events that threaten drinking water. In the metro Washington area, 75% of drinking water comes from the Potomac River. Across the basin there are 77 public water supply systems with surface water intakes. When spills occur, local emergency responders, state emergency management agencies, and federal agencies mobilize quickly to protect public health and minimize environmental impacts. For spills into the Potomac River and its major tributaries, ICPRB has a role in emergency response and on a continuing basis works with other agencies to maintain and even improve preparedness.

Spill Emergency Response

When notified of a spill ICPRB’s emergency response role is to alert downstream water utilities and water management agencies that a spill has occurred. Using ICPRB’s Emergency River Spill Model, the staff calculates contaminant concentrations and travel times to water intakes and share that information with the utilities and agencies.  The spill model can calculate travel times for the Potomac River mainstem from Cumberland to Little Falls, plus the Shenandoah, South Branch Potomac, and Monocacy rivers, and Antietam and Conococheague creeks. Staff members are trained to run the spill model and carry out our spill communication procedures and they share responsibility for responding to an event at any time. Every year, spill events occur that turn out to be insignificant threats to water supply but provide regular opportunities for practicing our spill response procedures.

Spill Protection Planning

ICPRB is working with government agencies and utilities to improve our knowledge of spill risks and improve preparedness for spill events. The work is generally under the umbrella of the Potomac River Basin Drinking Water Source Protection Partnership (DWSPP). ICPRB collaborated with other agencies in planning and executing spill exercises in 2008, 2012, and an upcoming exercise in June of this year. With each of these exercises the participating agencies gain a better understanding of the threats and identify gaps in response procedures that need to be addressed.

Prompted by a series of spill events in early 2014 (storage tank failure in Charleston, West Virginia; train derailment into the James River, Virginia; coal ash release into the Dan River, North Carolina), ICPRB began discussions with EPA Region 3 about updating the District of Columbia Source Water Assessment Plan (D.C. SWAP). A new D.C. SWAP has relevance to the entire Potomac basin upstream of Washington because the entire watershed is D.C.’s source water area and an inventory of threats to D.C. water supply can provide an inventory of threats to other water utilities in the basin. At the quarterly DWSPP meeting on February 24, the EPA representative said they hope the new DC SWAP will be “a model SWAP” for the nation.

Also in 2014, but on a separate track, the MWCOG received a grant from the Department of Homeland Security to undertake a variety of water security tasks, including an inventory of spill threats to drinking water for the metro Washington area. ICPRB and DWSPP participate in the planning for both projects.

Stay Informed

Looking to stay informed of spills in the Potomac River basin? Sign up for our Newsletter and follow us on Facebook and Twitter to get the updates.

An image of an icy river. A large military ship is in the background.

Road Salts & Water Quality

While a winter snow can lead to warm and cozy day at home, the de-icing materials used to keep traffic flowing can be negatively affecting water quality. This is especially true when the products are applied incorrectly or flow with runoff into nearby streams. Impacts are not isolated to the winter months. The road salt’s chloride can be stored in soil and groundwater only to be released into streams throughout the rest of the year. Chronic and acute chloride levels can harm both plant and animal life in and along streams. Additionally, high sodium content in sources of drinking water can lead to taste and odor challenges for water suppliers and be an issue for individuals restricted to a low-sodium diet.

To minimize the water quality impacts and maintain safe roads, some communities are exploring alternatives to road salts and changing application procedures around high quality and sensitive streams. Learn more about alternative products and application methods from the Potomac River Basin Drinking Water Source Protection Partnership and the Chesapeake Bay Program.

For more on information on increasing concentrations of chloride in U.S. streams, read “River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons,” from the U.S. Geological Survey. ICPRB works to address this issue through the Potomac River Basin Drinking Water Source Protection Partnership.