August 2009 USGS Maryland-Delaware-DC Water Conditions Summary

Water levels in August were normal in 72% of the streams and 69% of the wells used by the U.S. Geological Survey (USGS) to assess response to climatic conditions in Maryland, Delaware, and the District of Columbia. None of the streams had below normal levels in August, however, 5 wells had below normal water levels.

Precipitation

Rainfall was above normal in the Baltimore area and in Delaware, and less than 3 inches in western Maryland and the District of Columbia, according to the National Weather Service. The Hagerstown weather station does not have enough record to calculate statistics.

Rainfall varied greatly across the region, but remains normal for the year to date and for the last 365 days.

Source: National Weather Service
MD and DC: http://www.weather.gov/climate/index.php?wfo=lwx
DE: http://www.erh.noaa.gov/phi/
Middle Atlantic River Forecast Center: http://www.erh.noaa.gov/marfc/Maps/precip.html

Streamflow

Streamflow was normal in 72% of the 29 USGS streamflow stations used to assess climatic conditions in Maryland, Delaware, and the District of Columbia. The remaining 28% of streams were above normal.

In Delaware, the Brandywine and Choptanks Rivers were above normal.

Monthly mean streamflow on the Choptank River rose from normal levels in July to above normal in August. Water levels usually drop during the summer months and reach their lowest point in the fall. The dark line in the 5-year hydrograph represents the current flow and the white band shows the normal range based on the period of record.

Five-year hydrographs for these streams can be viewed at: http://md.water.usgs.gov/surfacewater/streamflow/

Groundwater

Groundwater levels were normal in 69% of the 26 wells used by the USGS to assess climatic conditions. The wells with below normal levels for the second straight month were in Baltimore, Carroll, and Washington Counties. The water level in the Somerset County well was the only well with above normal water levels.

The groundwater level in well SO Cf 2 in Somerset County, Maryland rose abruptly from normal to above normal levels in August. The nearest weather station in Georgetown had over 8 inches of rain in August. The 5-year hydrograph shows the water level as a dark line and normal (between the 25th and 75th percentiles) as a white band.

Five-year hydrographs for these wells can be viewed at: http://md.water.usgs.gov/groundwater/web_wells/current/water_table/counties/

Reservoir Levels

Water available from the Baltimore reservoir system (Loch Raven, Liberty, and Prettyboy) was 75.51 billion gallons in available storage at the end of August 2009.

Water stored in the Triadelphia and Duckett Reservoirs, which serve Montgomery and Prince George's Counties, rose to 99.55% capacity at the end of August 2009.

More Information

Maryland-Delaware-District of Columbia

USGS Drought Watch

USGS Water Summary

Streamflow

Groundwater

Chesapeake Bay

National

USGS Streamflow and Groundwater levels

U.S. Drought Monitor from the National Drought Mitigation Center

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Contact

U.S. Department of the Interior
U.S. Geological Survey

Wendy S. McPherson (wsmcpher@usgs.gov)
Maryland-Delaware-D.C. Water Science Center
5522 Research Park Drive
Baltimore MD, 21228
Phone:443-498-5555
Fax:(443-498-5510