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Literature Survey on BMP Reduction Efficiencies for Pathogens and Indicator Bacteria

November 10, 2015

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.

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The Future of Water Supply

November 9, 2015

ICPRB, on behalf of the major metropolitan area water suppliers, recently commissioned a study on the feasibility of using the Travilah Quarry in Rockville, Md., as a potential raw water supply storage facility. The quarry could serve as a supplement to existing water supply for the Washington Aqueduct, which supplies water to the District of Columbia via DC Water, and Washington Suburban Sanitary Commission. The Travilah Quarry study, and others like it, are being performed throughout the watershed.

This week, the Commission hosted the first of several round-table discussions with state agencies, water suppliers and additional stakeholders to discuss water markets and other promising tools for managing water scarcity. “One of the Commission’s most important roles is to bring people together to discuss the important issues facing the basin, and that is what we are trying to do in our new water markets discussion series,” says Dr. Cherie Schultz, Director of Operations for ICPRB’s CO-OP Section. ICPRB is also planning a study that explores the viability of additional water supply alternatives.

With some forethought and careful planning, we are confident that the future holds sufficient clean, healthy water for all who live in the Potomac River watershed. 

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ICPRB Receives Stormwater Stewardship Grant

October 27, 2015

Watershed Model

The Interstate Commission on the Potomac River Basin (ICPRB) has been awarded a Prince George’s County Stormwater Stewardship Grant that will bring watershed stewardship lessons to about 400 students and up to 13 teachers in Prince George’s County, Md. The grant supports ICPRB’s Score Four program in which students look into problems caused by stormwater runoff on their school grounds and then implement campus projects to reduce polluted stormwater entering their local streams.

Funded through Prince George’s County and administered by the Chesapeake Bay Trust, the goal of the County Stormwater Stewardship Grant Program is to encourage on-the-ground restoration activities that improve communities and water quality and to engage County residents in the protection of county waterways.

In ICPRB’s Score Four program students from Parkdale High School in Riverdale will tackle two problems – water pollution and hunger – by starting a campus Food Forest featuring native fruit and nut-bearing trees and shrubs. At Northwestern High School (Adelphi) and the Academy of Health Sciences at Prince George’s Community College students will undertake a series of stream and campus investigations that lead to the planting of Bay-Wise gardens to reduce polluted stormwater and beautify their campuses.

From the perspectives of involved teachers, the Score Four Program engages their students in every-day science, math, and social studies skills as they plan their restoration projects. At Northwestern High School, ICPRB is partnering with teacher Kari Rowe to deliver the program to newly immigrated students in her English-as-a-Second-Language classes. The government and biology teachers at the Academy of Health Sciences plan for their students to present their project in their school newspaper, at their science fair, and at a community presentation.

ICPRB staff members Rebecca Wolf and Nguyen Le are conducting the program. “We are excited to work with these teachers and students, helping them reduce their ecological footprint while meeting education goals for the students,” Wolf said. “Our biggest goals are for students to gain the inspiration, knowledge, and skills to become stewards of their streams.”

As part of this grant, ICPRB will provide Score Four training to teachers at a 3-day workshop in July, 2016, with the support of the Prince Georges County Public Schools and Chesapeake Natives, Inc.

Contact us for more information on the Score Four program or the teacher training.

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An aerial view of a housing development.

Study on the Effects of Impervious Cover on Streamflow

October 7, 2015

What makes streams most susceptible to the impacts of impervious cover?

A recently released study by ICPRB, entitled The Effects of Impervious Cover on Streamflow under Various Watershed Conditions in the Potomac Basin: Phase 1, found that impervious cover is particularly prone to altering streamflows in watersheds with steep slopes.  Small headwater streams are also especially susceptible to the impacts of impervious cover.  These initial findings are only a first part of the study.  Phase 2, scheduled for completion in September 2017, will explore the question using the latest data at a higher spatial resolution. You can read the full study on our website.

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

October 2, 2015

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

September 30, 2015

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

September 29, 2015

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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Metropolitan Washington Drinking Water Supply Adequate to 2035

September 2, 2015

The existing water supplies that serve more than four million residents can adequately meet demands through the Year 2035, according to a new study by the Interstate Commission on the Potomac River Basin (ICPRB). Drought conditions as severe as the worst drought on record will likely require some form of mandatory use restrictions, however.

Looking further to 2040, the current supply system could experience considerable stress requiring stronger use restrictions, and some reservoir resources may be exhausted. During a severe 2040 drought there also is a small probability that the flow of the Potomac River could drop slightly below the environmental flow guideline of 100 million gallons per day (mgd) as measured at Little Falls Dam.

The study also assessed possible effects of climate change on the system. The impact on water supply varies dramatically depending on the change in stream flow that may result from changes in precipitation and temperature. Results from this study indicate that in the event of a severe drought with 2040 forecasted demands, the following range of potential impacts on the system could be expected.

  • If summer flows fall by 10 percent or more: During a severe drought, most system reservoirs would be drained and on some days the system would be unable to meet water supply demands and the 100 mgd environmental flow-by at Little Falls.
  • If summer flows change by 0 to +10 percent: the moderate increase in flows would not be enough to prevent some water use restrictions from occurring during a severe drought; some reservoir storage could be seriously depleted.
  • If summer flows rise by 20 percent or more: a substantial increase in flows would increase metropolitan area water supplies sufficiently to allow the current metropolitan area system to meet forecasted 2040 demands.

The study makes several recommendations, including,

  • The region’s water suppliers should continue their efforts to identify and evaluate potential new water supply storage facilities and conduct an evaluation of the relative benefits of new storage facilities, non-structural changes in operations, and other options. Enhance flow forecasting abilities to allow more precise operation and avoidance of shortages.
  • Further develop ICPRB’s database and model of Potomac basin water withdrawals and consumptive use to provide a sound foundation for basin-wide water supply planning and for a planned basin-wide comprehensive plan.

The study is performed every five years by the ICPRB Section for Water Supply Operations on the Potomac River (CO-OP). The CO-OP works with the metropolitan area water suppliers to coordinate normally independent water supply operations during droughts, and studies the water supply system to improve operations and plan for its future reliability.

You can download the complete study on the ICPRB website.

The ICPRB CO-OP works closely with the Washington metropolitan area water utilities, Fairfax Water, the Washington Suburban Sanitary Commission, and the U.S. Army Corps of Engineers Washington Aqueduct Division, which collectively provide the bulk of potable water to the region’s residents. The suppliers usually operate independently, but work together with CO-OP during drought conditions to assure that all demands are met equitably. The CO-OP also provides important services, including annual drought exercises an analyses of potential changes to the existing system.

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Apply today! ICPRB seeks Communications Specialist

May 5, 2015

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.

Contact us for more information