In 2021, Commissioners of the Interstate Commission on the Potomac River Basin (ICPRB) passed a Resolution on Enhancing Water Supply Resilience for the Washington Metropolitan Area. This resolution is the first step in updating the two foundational agreements of the Washington metropolitan area cooperative water supply system: the Low Flow Allocation Agreement (LFAA) of 1978 and the Water Supply Coordination Agreement (WSCA) of 1982. To facilitate such an update the resolution called for the following action items:
- Develop a Task Force on the WSCA to reinitiate dialogue on revisions that would accurately reflect changing conditions. This includes the need for strengthening water security against spills, cybersecurity attack, and water scarcity and the ability to include additional suppliers;
- Convene a Work Group to discuss the ten sets of options identified in the 2018 review of the LFAA; and
- Convene scientific workshops on state-of-the-art approaches to environmental flows for large river systems.
To address the third action item, a virtual workshop was held over one-and-a-half days in May 2022, with the explicit purpose of answering the following questions with respect to the Potomac River, which supplies most of the Washington, D. C., metropolitan area drinking water:
- Are there other approaches now for determining environmental flows in large, relatively unregulated rivers like the Potomac?
- If there are, what data, analysis tools, and assessments are needed to make a scientifically defensible change?
The information presented and discussed during the workshop provides input to the LFAA workgroup in the event the group recommends revisiting the current environmental flow-by target used during low flow periods. The question of whether or not to study the flow-by was informally discussed during the workshop but the intent of the workshop was to gather the relevant information, not recommend a course of action.