Water Levels Remain at Record-Setting Lows
U.S. Department of the Interior
U.S. Geological Survey
Wendy McPherson (email@example.com)
Maryland-Delaware-D.C. Water Science Center
5522 Research Park Drive
Baltimore, MD 21228
Updated: October 3 , 2002
Near normal rainfall in September had little effect on groundwater levels in parts of Maryland. Streamflows increased, although only temporarily in some locations. With a little luck, we may have seen the lowest water levels we will see until next summer. October 1 begins the new water year, when water levels are expected to increase because less water evaporates or is used by plants. Temperatures have been warm, however, extending the growing season, and the deficit in groundwater levels is so large that without an exceptionally wet winter to recharge the groundwater system, water levels may be very low again next year.
Average streamflow at the Potomac River near Washington, D.C. during the 2002 water year was the lowest since record-keeping began in 1930. New daily record low flows were set for 9 days during September and 72 days for the water year. Monthly streamflow for the Potomac was 52 percent of normal (see graphs at http://md.water.usgs.gov/monthly/poto.html).
Groundwater levels continued to decline in September across Maryland and Delaware, setting many monthly and all-time record low levels. Four of the 17 wells used for drought analysis in Maryland and Delaware were in the normal range, while the remaining 13 wells had below normal water levels at the end of September, 9 wells set monthly record lows for September, and 7 of these wells set all-time record lows (since record-keeping began in 1962), according to hydrologists at the U.S. Geological Survey (USGS).
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In Maryland, water levels in wells in Baltimore, Charles, Harford, Montgomery, Queen Annes, and Somerset Counties reached the all-time lowest level since record-keeping began in 1962 (see attached table), breaking the records set during the 1966, 1981, and 1999 drought years. These wells and two additional wells from Carroll and Prince Georges Counties set record lows for September.
The drought monitoring well with the largest departure from normal is in Harford County, Maryland. The groundwater level at this well was 6.02 feet below normal at the end of September, surpassing the previous September record set in 1966 by 1.94 feet and setting a new all-time record low. In Baltimore County, Maryland, the 5-year hydrograph shows that the groundwater level has been dropping since summer 2001, indicating that rainfall has not recharged the groundwater system at all during 2002 (see graphs at http://md.water.usgs.gov/groundwater/).
The groundwater level in a real-time well located in Kent County, Delaware rose by more than half a foot in August and has maintained the higher level in September. Real-time groundwater levels and streamflow are monitored by the USGS across the Nation at 15-60 minute intervals and the data are transmitted via satellite to USGS offices every 1 to 4 hours. This information can be viewed within minutes of arrival at: http://waterdata.usgs.gov/.
Remnants of Tropical Storm Isidore, which passed to the west of most of Maryland, left abundant rainfall across most of Maryland and part of Delaware. This rainfall helped streamflow levels recover somewhat, especially in the west-central part of Maryland, such as Frederick County. Streamflows during the last 7 days of September ranged from below normal to normal, and even above normal at real-time streamflow stations across Maryland and Delaware. However, record low monthly streamflows were recorded at Deer Creek and Patuxent River in Maryland, and Brandywine Creek in Delaware. These sites and Antietam Creek also set new daily lows for more than 13 days in September. Streamflow on the Choptank River near Greensboro, Maryland was 21 percent above normal. Five-year streamflow hydrographs can now be viewed on the USGS website at: http://md.water.usgs.gov/surfacewater/streamflow/.
Average streamflow at Deer Creek in Harford County, Maryland was below normal during the entire 2002 water year. New daily record lows were set for 206 days at Deer Creek. September flow was 66 percent below normal. Streamflow at Deer Creek has been below normal for 16 of the last 17 months, and set daily low streamflow records for 13 of the 30 days in September. This is the eighth consecutive month with record-setting monthly low streamflow for Deer Creek.
Total flow into the Chesapeake Bay during September averaged 8.27 bgd (billion gallons per day), which is 61 percent below average. This is the fourth lowest September flow to the Bay since 1964 (5.47 bgd). (see graphs at http://md.water.usgs.gov/monthly/bay.html.) For the 2002 water year (October 2001 through September 2002), the total inflow to the Chesapeake Bay was 342 bgd, which is 15 percent less than the 2001 water year (403 bgd).
The Baltimore region has been supplementing its water supply with water from the Susquehanna River since the end of January. Streamflow on the Susquehanna River reached low levels that required Maryland water suppliers to reduce the amount of water withdrawn from the river and increased the amount of water withdrawn from reservoirs. The result was a 6-percent decline in storage of the Baltimore Reservoir System since August. Storage in the Baltimore Reservoir System was 42 percent of capacity at the end of August, and the contents of the Triadelphia and Duckett Reservoirs on the Patuxent River were at 43 percent of capacity.
September rainfall was near normal across Maryland and Delaware, and because the average temperature was higher than normal, most of the rainfall evaporated or was used by plants, resulting in minimal recharge to groundwater aquifers. Only about 5 percent of the rain became runoff, or contributed water to streams. This indicates that more than 95 percent of the water evaporated, was used by plants, or remained in the soil and possibly recharged groundwater. The rapid decline in streamflows after a rainfall event is caused by the low groundwater storage. During periods of no rainfall, streamflows are maintained by groundwater storage, but because of low groundwater levels, less base flow is contributed to streams, and water levels have been at record lows for many months in central Maryland. Streamflow and groundwater levels reflect the long-term effects and severity of the hydrologic drought.
Up to date drought information can be found at
Tracking streamflow and groundwater levels is essential to gauge drought severity and recovery. 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 how the drought is affecting streamflow and groundwater levels in Maryland and Delaware, see Drought Watch at: http://md.water.usgs.gov/drought/.
Please note that the streamflow and groundwater level data is provisional and subject to change.
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/
Five-year streamflow hydrographs can now be viewed at: http://md.water.usgs.gov/surfacewater/streamflow
The real-time streamflow stations used in this analysis are operated in cooperation with the Maryland and Delaware Geological Surveys, the Maryland State Highway Administration, the U.S. Army Corps of Engineers, the Maryland Department of Natural Resources, the Maryland Department of the Environment, and other agencies. The observation wells used in this analysis are operated in cooperation with the Maryland and Delaware Geological Surveys. The USGS publishes data for 128 streamflow stations and 379 wells across Maryland and Delaware.
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 * * *
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- 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
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- 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
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- 12-04-2003 More Record-High Water Levels in November 2003
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- 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
- 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
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- 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
- 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
- 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
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