Drought Conditions Lead to 10 Record Low Monthly Groundwater Levels in July

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: August 6, 2002

Current groundwater levels in Maryland and Delaware are lower in most wells than during the droughts of 1999 and the 1960s. Low groundwater and streamflow levels continue to reflect the long-term effects of hydrologic drought. Groundwater levels were below normal at the end of July at all of the 17 wells used for drought analysis in Maryland and Delaware, according to hydrologists at the U.S. Geological Survey (USGS). Ten of these wells set record low groundwater levels for July (see graphs and a record comparison table at http://md.water.usgs.gov/groundwater/).

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

At the end of July, record low 7-day streamflows were set at three real-time streamflow stations used to monitor drought in Maryland and Delaware. Real-time streamflow is monitored by the USGS across the Nation and can be viewed at: http://waterdata.usgs.gov/. Streamflow in western Maryland was above normal at the end of July because of rainfall at the end of the month. During droughts, streamflow typically declines to levels experienced before rainfall within a few days.

The USGS drought monitoring well with the largest deficit from normal is in Carroll County, Maryland. The groundwater level at this well is 8.20 feet below normal for July, surpassing the previous July record set in 1995 by 3.04 feet. The monitoring well in Harford County, Maryland, is 7.81 feet below normal for July, and has exceeded the previous record low set in July 1965 by 3.59 feet.

July 2002 Record Low Monthly Groundwater Levels
County	Well Name	July Water Level*	Record Water level*	Date	Exceeds Record by (feet)	Normal Water Level*	Departure from Normal (feet)
Baltimore	BA Ce 21	>21.96	>20.17	>1963	>1.81	>17.79	>4.15
Baltimore	BA Ea 18	>27.16	>25.24	>1963	>1.92	>21.05	>6.11
Baltimore	BA Ec 43	>4.30	>4.17	>1969	>0.13	>3.07	>1.23
Charles	CH Ee 16	>16.10	>15.93	>1968	>0.17	>14.89	>1.21
Carroll	CL Bf 1	>74.95	>71.91	>1995	>3.04	>66.75	>8.20
Harford	HA Bd 31	>18.84	>15.25	>1965	>3.59	>11.03	>7.81
Montgomery	MO Eh 21	>16.93	>16.17	>1999	>0.76	>13.37	>3.56
Queen Annes	QA Cg 1	>6.12	>5.74	>1966	>0.38	>4.26	>1.86
Queen Annes	QA Ec 1	>6.32	>6.26	>1988	>0.06	>4.57	>1.75
Somerset	SO Cf 2	>6.16	>6.16	>1986	>0.54	>4.25	>1.91
* Water levels are in feet below land surface

In Baltimore County, Maryland, the USGS real-time well is 6.11 feet below normal and has broken the previous record by 1.92 feet. This well is equipped with instruments to record water-level data at 15-60 minute intervals and transmits the data via satellite to USGS offices every 1 to 4 hours, which can be viewed within minutes of arrival at http://waterdata.usgs.gov/md/nwis/uv/?site_no=392045076512501. The 5-year hydrograph below shows the groundwater level dropping since last summer, indicating that spring and summer rainfall has not recharged the groundwater aquifer.

Hydrographs and other detailed information regarding 22 water table wells and 12 confined aquifers are available at: http://md.water.usgs.gov/groundwater/index.htm

A recent addition to the USGS website is a clickable groundwater map for the metropolitan Washington, D.C. area: http://md.water.usgs.gov/groundwater/web_wells/current/water_table/counties/cog/. The website features 17 observation wells measured monthly and plotted in comparison to normal groundwater levels.

This map can be explored in detail at:
http://md.water.usgs.gov/groundwater/web_wells/current/water_table/counties/cog

Record low 7-day streamflow was observed at Deer Creek and Winters Run in Harford County, Maryland, and Brandywine Creek in New Castle County, Delaware. Average streamflow at Deer Creek in Harford County, Maryland, was the lowest monthly July flow for the period of record at 84 percent below normal. Streamflow at Deer Creek has been below normal for 14 of the last 15 months and set daily low streamflow records for 29 out of the 31 days in July. This is the sixth consecutive month with record-setting monthly low streamflow for Deer Creek. In the Potomac River Basin, the Monocacy River has also been particularly hard hit, breaking daily records for 15 of the 31 days in July.

Total flow into the Chesapeake Bay during July averaged 13.6 bgd (billion gallons per day), which is 45 percent below average. Streamflow in the Susquehanna River decreased in July, contributing 52 percent of the total flow into the Chesapeake Bay. Streamflow in the Potomac River averaged 1.4 bgd, which is 56 percent below normal for this time of year. The lowest Potomac River flow was on July 13 at 0.7 bgd (see graphs at http://md.water.usgs.gov/monthly/poto.html. Streamflow on the James and Potomac Rivers increased in July, but remained below normal. The James River contributed 10 percent of the flow to the Bay, while the Potomac River contributed 15 percent (see graphs at http://md.water.usgs.gov/monthly/bay.html).

July rainfall varied widely across the bi-state area, and temperatures were above average throughout the area. Western Maryland experienced above-normal precipitation, while most of the rest of Maryland and Delaware generally received below-normal precipitation. Rainfall at Baltimore-Washington International (BWI) Airport was 1.47 inches below normal, and rainfall at Reagan Washington National Airport was reported at 1.6 inches below normal, according to the National Weather Service. Annual rainfall is more than 10 inches below normal in many counties across Maryland and Delaware.

Storage in the Baltimore reservoir system declined to 55 percent of capacity in July. The Baltimore region has been supplementing its water supply with water from the Susquehanna River since the end of January. Near month's end, the contents of the Triadelphia and Duckett Reservoirs were at 61 percent of capacity.

Rainfall from scattered thunderstorms may temporarily raise streamflow levels, but most of the rainfall in the summer is used by plants or evaporates, resulting in minimal recharge to groundwater aquifers. The rapid decline in streamflows after a rainfall event is explained by the low groundwater storage. Streamflows in the summer normally are maintained by groundwater storage, which typically is highest in early spring, yet 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, and generally do not recover during the summer months.

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.

The real-time streamflow stationsused 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 U.S. Geological Survey 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