The ICPRB Section for Cooperative Water Supply Operations (CO-OP) commenced its fourth “Drought Monitoring” period of the year on November 1. CO-OP initiates drought monitoring when the flow at the U.S. Geological Survey (USGS) stream gage in Point of Rocks, Maryland, falls below 2,000 cubic feet per second. Due to the persistent dry conditions, the publication period for the Water Supply Outlook has been extended into November, even though the ICPRB’s Low-Flow Outlook model does not cover this month. The Potomac basin upstream of Washington, D.C., received 0.8 inches of rain in October, which is 2.2 inches below normal. Streamflow is currently below normal. Groundwater levels are below normal in many observation wells in the basin. The U.S. Drought Monitor reports that 19% of the Potomac basin is experiencing severe drought conditions, while 52% is facing moderate drought conditions. Extreme drought conditions remain in a small western corner of the basin. Many counties in Pennsylvania, as well as a few drought regions in Virginia and Maryland, are currently under a drought watch. Two counties in Pennsylvania are under drought warning. The drought watch declared on July 29 by the Metropolitan Washington Council of Governments (MWCOG) is still in effect. The Climate Prediction Center indicates that normal precipitation is likely over the next three months. The U.S. Seasonal Drought Outlook indicates that drought removal is likely in the central parts and eastern parts of the Potomac Basin over the coming months, while drought is likely to remain but improve in western areas. At present, there is sufficient flow in the Potomac River to meet the Washington metropolitan area’s water demands without releasing water from upstream reservoirs. If low-flow conditions further develop, the Washington metropolitan area is protected from a water supply shortage owing to carefully designed drought-contingency plans.

Image: Adjusted flow at Little Falls on the Potomac River for 1999, 2002, and 2024 as of November 12, 2024.