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ICPRB 4th Quarter Business Meeting August 31, 2021

The Interstate Commission on the Potomac River Basin (ICPRB) will hold its quarterly business meeting virtually on August 31, 2021.

The Section for Cooperative Water Supply Operations on the Potomac (CO-OP) will begin at 8:30 a.m. and will feature an update on efforts to increase supplemental storage for the metropolitan area water supply.

The ICPRB meeting will begin at 9:45 a.m. Commissioners will get an update on the Land Prioritization Project, which assists planners in targeting land conservation efforts that can benefit drinking water source quality and ongoing enhancements to spill modeling to protect drinking water and water quality from contamination. The commissioners also will receive a report on ICPRB’s evolving Justice, Equality, Diversity, and Inclusion policy.

Members of the public who wish to view the proceedings should send a request through our Contact Us page no later than close-of-business on August 26. You will be sent a link to the meeting.

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Commission passes resolution to review water supply agreements

June 22, 2021

Curtis Dalpra, Communications Manager
Office: (301) 274-8107

Commission to Review Interstate Agreements to Assure Reliable Drinking Water for the National Capital Region

ROCKVILLE, Md. – On June 15, 2021, an interstate body resolved to re-examine the agreements that for 40 years have provided reliable and clean drinking water to the National Capital Region with the goal of guaranteeing a reliable supply in the future.

In 1963, the U.S. Army Corps of Engineers proposed construction of 16 large reservoirs in the Potomac River basin to meet the future demand for drinking water and other water resource needs. Although the plan met significant public resistance, the drought of 1966 showed that something needed to be done.

In the late 1970s and early 1980s, the Interstate Commission on the Potomac River Basin (ICPRB) led negotiations to establish what was at the time a revolutionary cooperative arrangement enshrined in the Low Flow Allocation Agreement (LFAA), the Water Supply Cooperation Agreement (WSCA), and related accords. Created by Congress as an independent inter-jurisdictional organization, ICPRB is particularly well suited to engage in multi-state coordinated cooperative functions. Time has demonstrated that the coordinated operation of the resources has allowed the water suppliers to meet demands because of synergistic gains in total yield realized under the cooperative management strategies.

Recently, the ICPRB’s Work Group on Water Supply suggested a Resolution to establish a process for reviewing these agreements. In presenting the Resolution to the Commission, Chairman Willem Brakel reviewed the history of these landmark agreements but acknowledged the need for updates. “That framework served us admirably for over four decades, but increasingly we have started to realize that these original agreements are becoming outdated, outmoded and less than fully capable of meeting the region’s needs and challenges as conditions change over the coming years and decades,” he stated.

The review will be staffed by ICPRB’s Section for Cooperative Water Supply Operations on the Potomac (CO-OP), which conducts annual drought exercises that help guarantee a reliable supply of drinking water for the DC metropolitan area.

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William Willis appointed Pa. Commissioner

The ICPRB staff and commissioners welcome William J. Willis as a Pennsylvania commissioner. Willis teaches at the Mercersburg Academy in Mercersburg, Pa., where he is the Director of Environmental Initiatives and an environmental science teacher.

Willis led the creation of an environmental master plan for the school, and chairs the environmental committee. His efforts cover environmental initiatives in all elements of school life, including facilities, student engagement, community outreach, residential life, administrative planning, and curriculum. He also conducts monthly stream monitoring with students and local citizens as a cofounder of the Johnston Run Revitalization Team.

Since coming to the academy in 2001, Willis has worked in many other aspects of the school, including director of International Programs, and alumni and annual giving.

Willis previously worked in education marketing and served as director of the nonprofit Bitterroot Ecological Resources, Inc., working to increase public awareness and engagement in the Bitterroot River Valley in Montana.

Willis past and current activities make him well-suited to help with similar efforts in the Potomac watershed, and ICPRB looks forward to seeing his science and outreach skills bring a positive impact. Welcome aboard!

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ICPRB Working Cooperatively to Improve Cleanup Accuracy

A new study by ICPRB biologist Claire Buchanan and other authors has provided an improved method for assessing nutrient levels in the surface waters of the Chesapeake Bay and will provide an improved way to judge the effects of nutrient reduction best management practices. The regional Chesapeake Bay cleanup is based on reducing nutrients and sediments to restore the waterway’s health. Excessive nutrient levels contribute to algae blooms that cause a succession of water quality problems. Buchanan teamed with scientists from the University of Maryland, the Environmental Protection Agency, U.S. Geological Survey, Maryland Department of Natural Resources, and the Chesapeake Research Consortium to produce Nutrient limitation of phytoplankton in Chesapeake Bay: Development of an empirical approach for water-quality management.

The model can help direct future efforts in nutrient reduction through improved modeling that can increase effectiveness and reduce costs. Future research will focus on the Potomac and other bay tidal tributaries.

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ICPRB welcomes Bay Executive Council Statement on Diversity, Equity, Inclusion, and Justice

The ICPRB welcomes the Statement in Support of Diversity, Equity, Inclusion and Justice signed on August 18, 2020 by the Chesapeake Bay Program (CBP) Executive Council, which includes all parties to the ICPRB Compact.  As a longstanding CBP participant and partner, the ICPRB fully shares the commitments articulated in the above-referenced Statement, which echo and amplify references in the ICPRB’s Manual of Operations and the recently adopted ICPRB Revised Strategic Plan for 2020-2023 to a diverse workforce, broader outreach, marginalized/vulnerable communities and environmental justice.

A close-up of a man's face.

The Passing of a Commissioner

The ICPRB is saddened to announce the death of former Pennsylvania Commissioner Andy Zemba. Mr. Zemba, 50, passed away at his home on January 3. He was the director of the Interstate Waters Office of the Pennsylvania Department of Environmental Protection (DEP). His responsibilities as an ICPRB Pennsylvania Commissioner had recently been assumed by DEP Special Secretary of Water Resources Planning Kelly Heffner.

Mr. Zemba was appointed a Pennsylvania commissioner in 2011, served on the executive committee, served as vice-chairman in 2014 and chairman in 2015. During his tenure, Mr. Zemba worked closely with ICPRB in efforts to help with Pennsylvania’ Water Resources Planning Act, which involves stakeholders in planning for sustainable water resources. Mr. Zemba worked with ICPRB, which helped to assess needs and develop plans in the state’s Potomac drainage.

As vice-chairman, and later chairman, Mr. Zemba helped ICPRB administrate a range of efforts. He brought with him a positive attitude toward the ICPRB, and was always constructive in guiding the commission in protecting and preserving the waters of his state and the basin. We thank him for his many efforts and contributions. He is missed by the commission and Pennsylvania.

For information on the services or to send condolences to the Zemba family, please visit:

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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, Wainger 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.

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