Streamflow and Groundwater Levels High in May

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

Contact:
Wendy McPherson (wsmcpher@usgs.gov)
Maryland-Delaware-D.C. Water Science Center
5522 Research Park Drive
Baltimore, MD 21228
Phone:(443)498-5500
FAX: (443)498-5510

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Updated: June 4, 2003

A very rainy May led to above normal streamflow and groundwater levels in many streams and wells across Maryland and Delaware, according to hydrologists at the U.S. Geological Survey (USGS) in Baltimore. Groundwater levels were above normal in all but three of the wells used by the USGS to monitor climatic conditions in the bi-state region for May. Streams across the region were also flowing above normal and some have set new daily high and monthly records.

Cool temperatures and slow-moving storms caused persistent rainfall in during May 2003 that led to an extremely wet month. May 2003 was the wettest month since September 1999, when tropical storm Floyd engulfed the region, according to the National Weather Service. It was the sixth wettest May for Washington, D.C. and the seventh wettest May for Baltimore.

For news release and images, visit:
http://md.water.usgs.gov/publications/press_release/current

Groundwater levels are expected to drop during the growing season because of increased demand, but the abundant rainfall has raised groundwater levels, recharged the aquifers, and saturating the soil, making it difficult for farmers. Wells in Charles and Queen Annes Counties, Maryland set monthly high records. This is a large contrast to 2002, a drought year, when eight wells were setting monthly low records. For 5-year hydrographs of groundwater levels, visit: http://md.water.usgs.gov/groundwater/.

Streamflow levels have also been above normal across Maryland and Delaware at the end of May. With groundwater and streamflow levels already high, there is the potential for localized flooding. The average monthly streamflow at the Potomac River near Washington, D.C. was 22.0 bgd (billion gallons per day), or 132 percent above normal (see graphs at http://md.water.usgs.gov/monthly/poto.html). Streamflow data can be monitored on the web at http://waterdata.usgs.gov/nwis/rt. Five-year monthly streamflow hydrographs can be viewed on the USGS website at http://md.water.usgs.gov/surfacewater/streamflow/.

Total flow into the Chesapeake Bay during May averaged 87 bgd (billion gallons per day), which is 36 percent above average. For the first 5 months of this year, the flow into the Bay has averaged 92.1 bgd, which is about twice the amount the first 5 months of last year (45.8 bgd). Average flow for the 5-month period was 76.4 bgd, resulting in 20 percent more total flow than average. During the drought over the past 2 years, water clarity conditions in the Bay have improved because less nutrients and sediment were flowing into the Bay. Conditions have changed this spring because of increased flow. The graph below shows the total flow into the Chesapeake Bay at different locations along the Bay (see http://md.water.usgs.gov/monthly/bay.html). The dashed line shows the monthly mean inflow. There were several months below normal during the drought years of 2001 and 2002. In 2003, the total flow has been above average.

The possible consequences of increased streamflow into the Bay include degraded water-quality conditions in the spring and summer as larger amounts of nutrients and sediment are carried into the Bay. Higher nutrient levels lead to algal blooms, which can decrease the amount of dissolved oxygen in the Bay and result in fish kills. The algal blooms, along with increased amounts of sediment, can cause a decrease in the light needed by the underwater grasses in the Bay. The grasses are important habitat for crabs and food for waterfowl. More information about water quality and the Chesapeake Bay can be found at http://md.water.usgs.gov/monthly/bay.html.

Streamflow and groundwater levels are used to gauge water conditions and may be used to predict the potential for flooding and drought conditions. These USGS data have been provided to State and local water resource managers and are critical for making appropriate decisions on water restrictions. For more information on streamflow and groundwater levels in Maryland and Delaware, see Water Watch at: Water Watch.

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

Groundwater Levels in the Metropolitan Washington D.C. Area can be seen at http://md.water.usgs.gov/groundwater/web_wells/current/water_table/counties/cog/

The USGS, a bureau within the Department of the Interior, is the Nation's largest water, earth and biological science, and civilian mapping agency providing reliable, impartial scientific information to resource managers, planners, and other customers. This information is gathered in every state by USGS scientists to minimize the loss of life and property from natural disasters, contribute to the sound conservation and the economic and physical development of the Nation's natural resources, and enhance the quality of life by monitoring water, biological, energy, and mineral resources.

** * USGS * * *

In-depth information about USGS programs may be found on the USGS home page at http://www.usgs.gov and http://chesapeake.usgs.gov/ for Chesapeake Bay activities.

Archived News Releases 2000-Present

2006

• 01-06-2006 Water Resources Plentiful at End of December 2005; Chesapeake Bay Flow Normal in 2005

2005

• 07-06-2005 Water Levels Fall as Summer Arrives
• 04-06-2005 March 2005 Water Levels Near Normal
• 03-04-2005 Flow Below Normal in Potomac River and Chesapeake Bay
• 02-07-2005 January 2005 Water Levels Normal to Above Normal
• 01-07-2005 2004 Ends with Normal to Above Normal Water Levels

2004

• 12-04-2004 Water Levels Remain Generally Above Normal
• 11-04-2004 Dry October Causes Water Levels to Drop
• 10-06-2004 Highest September Flow to the Chesapeake Bay Since 1937
• 09-03-2004 August Hurricanes Raise Water Levels in Southern Maryland
• 08-06-2004 Localized Flooding in Northeastern Maryland and Delaware in July
• 07-07-2004 Water Levels Normal to Above Normal in June
• 06-04-2004 Streams Return to Normal Levels in Maryland and Delaware during May 2004
• 05-06-2004 Streams Rise to Above Normal Levels in Maryland
• 04-07-2004 Streamflow and Groundwater Levels Fell in March 2004
• 03-04-2004 Streamflow and Groundwater Levels Normal to Above Normal in February 2004
• 02-04-2004 Cold, Dry January Leads to Drop in Water Levels
• 01-06-2004 Wettest Year Leads to Record-High Water Levels Including Third Highest Flow to Chesapeake Bay in December and 2003

2003

• 12-04-2003 More Record-High Water Levels in November 2003
• 11-04-2003 Record High Groundwater Levels in October 2003
• 10-03-2003 Flow to Chesapeake Bay in Water Year 2003 Second Highest Since 1937
• 09-05-2003 Third Consecutive Month of High Flow into the Chesapeake Bay
• 08-06-2003 Flow into Chesapeake Bay near Record High Levels
• 07-07-2003 Record Breaking High Water Levels in Maryland and Delaware
• 06-06-2003 Streamflow and Groundwater Levels High in May
• 05-07-2003 April Water Levels Normal
• 04-05-2003 Water Levels High in March - Water Restrictions Lifted
• 03-05-2003 Exceptionally Wet February Leads to High Water Levels
• 02-06-2003 Maryland and Delaware Streamflow and Groundwater Levels Remain Normal in January 2003
• 01-07-2003 2002: A Record-Setting Year for Low Groundwater Levels - Water Levels Recover to Normal in December 2002

2002

• 12-01-2002 Hydrologic Drought Wanes as Water Levels Rise
• 11-01-2002 Water Levels Rise Across Maryland and Delaware, But Drought Persists in Some Areas
• 10-03-2002 Water Levels Remain at Record-Setting Lows
• 09-05-2002 Groundwater in Parts of Maryland Reaches Lowest Levels Since 1962, Despite Late August Rains
• 08-06-2002 Drought Conditions Lead to 10 Record Low Monthly Groundwater Levels in July
• 07-03-2002 Record Low Water Levels Show the Effects of Long-Term Hydrologic Drought
• 06-04-2002 Groundwater Levels Reflect Long-Term Effects of Drought
• 05-02-2002 April Showers Not Enough to Raise Groundwater Levels
• 04-05-2002 The Drought in Full Bloom: Low Water Levels Result in Water Restrictions

2001

• 12-03-2001 Record Low Water Levels Set in November
• 11-02-2001 Dry October Leads to Low Water Levels
• 10-05-2001 Water Levels Low in Northern Maryland
• 09-07-2001 Water Levels Stable in August
• 08-06-2001 High and Low Water Levels in July
• 07-06-2001 Water Levels Continued to Improve in June
• 06-06-2001 Needed Rain Helps Avert a Drought in May
• 05-08-2001 Water Levels Still Normal in April, but More Rain is Needed
• 04-05-2001 Spring Rains Help Water Levels
• 03-06-2001 Water Levels Improve, But Are Still Below Normal
• 02-06-2001 Streamflow Still Low in Maryland in January
• 01-05-2001 Streamflow to Chesapeake Bay in 2000 Reflects Dry Autumn

2000

• 12-05-2000 Streamflow in Maryland Beginning to Show the Effects of Lack of Rain
• 11-07-2000 Despite Lack of Rain October Water Conditions near Normal
• 10-06-2000 September Water Conditions Above Normal in Maryland, Delaware, and D.C.
• 09-08-2000 August Water Conditions Above Normal in Maryland, Delaware, and D.C.
• 08-07-2000 July Water Conditions Continue Normal in Maryland, Delaware, and D.C.
• 07-07-2000 June Water Conditions Normal in Maryland, Delaware, and D.C.
• 06-06-2000 Water conditions begin to decline in Maryland, Delaware, and D.C.
• 05-05-2000 Water Conditions Continue to Improve in Maryland, Delaware, and D.C.
• 04-07-2000 Water Conditions Continue to Improve in Maryland, Delaware, and D.C.
• 03-07-2000 Water Conditions Improving in Maryland, Delaware, and D.C.
• 02-08-2000 January Streamflow and Groundwater Levels Still Low
• 01-06-2000 1999 Flow Into Chesapeake Bay Lowest Since 1960s Drought