ICPRB Releases Water Supply Alternatives Study

September 8, 2017

The region’s future demands more drinking water.

Here is how we can get it.

ICPRB Releases Water Supply Alternatives Study

When residents of the Washington metropolitan area turn on their taps, clean reliable drinking water comes out. This daily event, taken completely for granted, is a testament to decades of careful planning, investment and cooperation among area water suppliers assisted by the Interstate Commission on the Potomac River Basin (ICPRB). The investment in planning continues with the release of a report presenting options to increase drought protection for the Washington metropolitan area’s drinking water system, which will become inadequate in several decades.

A new ICPRB CO-OP study assesses a range of solutions to increase the capacity of the region’s water supply, which could fail to meet unrestricted demands by 2040. “Washington Metropolitan Area Water Supply Alternatives,” provides information on alternatives out to 2085 to help ensure strategic options are available over that planning horizon. Alternatives were evaluated by their abilities to maintain reliability in the face of growing metropolitan area water demand, decreasing river flows due to upstream use, and the potential impacts of climate change.

Options to augment future supply are the subject of ongoing assessments by metropolitan area water suppliers. Some of the options include construction of new facilities, such as converting stone quarries to water storage reservoirs that would directly provide water to one or two suppliers. They would provide regional benefits by increasing Potomac River flows during times of low flow. These alternatives would require significant investments in new infrastructure that include new underground conduits to transfer raw and/or treated water from one part of the supply system to another. Other alternatives include better flow forecasting models, changes to how existing reservoirs are operated, reductions in consumptive use, more stringent water use restrictions, and other proposals. These operational alternatives would entail some costs associated with new cooperative agreements, contracts between water suppliers, and

investment in research to develop new operating tools and policies. The study identified combinations of infrastructure and operational alternatives that should be in place to ensure system reliability in the future. For the 2040 planning horizon, two alternative options for phased quarry storage implementation and operational enhancements were recommended for consideration and further refinement. The two alternatives were selected to ensure system reliability for a moderately severe drought with conservative estimates of climate change impact.

Considerations include protecting the region from shortfalls leading up to 2040 and the need for broader regional cooperation to prepare for more severe challenges that may occur in the decades after 2040. Over a longer-term planning horizon, study results indicate that most of the alternatives will be needed to ensure future reliability by 2085.

“This is another step forward in our long term commitment to meet our region’s water supply demands,” said ICPRB Executive Director Carlton Haywood. “Our water supply is reliable  because water providers and regulators comprehensively plan for the region’s future. The level of planning, cooperation, and execution in this area is why we are studied as innovators by other regions,” Haywood said.

The ICPRB’s Section for Cooperative Water Supply Operations on the Potomac River (CO-OP) studies water use in the region, organizes coordinated utility operations during droughts, and assesses the reliability of current and future raw water supplies. The ICPRB also helps basin water suppliers protect the region’s drinking water sources.

The report is being assessed by the area water suppliers, who will soon decide on a course of action. An executive summary and the full report, “Washington Metropolitan Area Water Supply Alternatives” are available on our website. Contact us for more information.

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