Wettest Year Leads to Record-High Water Levels Including Third Highest Flow to Chesapeake Bay in December and 2003

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: January 6, 2004

Only one year after the region’s most severe hydrologic drought, many months of above normal precipitation have made 2003 the wettest year on record in Baltimore, according to the National Weather Service. Abundant precipitation has led to record high streamflow and groundwater levels across Maryland and Delaware, and the third highest flow to the Chesapeake Bay since record-keeping began in 1937 for December and 2003. Monthly mean streamflow at three streams was at its highest December flow since the 1940s. Groundwater levels at ten wells were at their highest December levels in 40 years, and for three of these wells, it was the fourth consecutive month of record high levels, according to hydrologists at the U.S. Geological Survey (USGS).

Although streamflow and surficial groundwater levels are high, water levels in some of the deep aquifers in southern and eastern Maryland continue to decline because the aquifers are being pumped more quickly than they can be recharged.

Chesapeake Bay

Monthly mean streamflow into the Chesapeake Bay during December was the third highest since record-keeping began in 1937. Flow averaged 118.6 bgd (billion gallons per day), which is more than twice the normal December flow into the Bay. The flow to the Chesapeake Bay graph shows the flow in 2003 was above normal for every month except February and was at near record highs for five of the last six months. In 2002 the flow was below normal for 8 months.

Flow to the Chesapeake Bay during calendar year 2003 was the third highest annual flow with 86.4 bgd. This flow was only 2.3 bgd below the record set in 1972. Flow has been above average since March 2003, which has contributed to higher amounts of nutrients and sediments entering the Bay.

The Chesapeake Bay watershed (below) covers more than 64,000 square miles in six states (New York, Pennsylvania, Maryland, Delaware, Virginia and West Virginia) and the District of Columbia. The highest percentage of flow to the Bay comes from the Susquehanna River. The following rivers (see table below) contributed various percentages of flow to the Bay in 2003.

More information about streamflow, water quality, and the Chesapeake Bay can be found at http://chesapeake.usgs.gov/ and www.chesapeakebay.net.

Precipitation

Precipitation during 2003 at the weather station in Baltimore, Maryland was 62.66 inches, which is more than 20 inches above normal and the wettest year since 1889, according to the National Weather Service. Precipitation in Washington, D.C. for 2003 was the second highest on record, only one-half inch below the record set in 1889. Annual precipitation for both regions is about 40 inches. Delaware and surrounding states in the northeast United States have all had above normal precipitation in 2003.

Abundant snow and rainfall has left groundwater and streamflow levels across Maryland and Delaware at very high levels. Since the ground is nearly saturated, when it rains, the water has little place to go except to accumulate in low-lying areas or become runoff and fill our waterways. The high water levels make the region vulnerable to localized flooding.

Status of Streams and Wells for December 2003

The map to the right shows the wells and streams used by the USGS to monitor water conditions in Maryland, Delaware, and Washington, D.C. In December, all wells and most streams were at above normal levels (dark circles and triangles). Ten wells were at their highest December levels in 40 years (represented by an asterisk). Three streams had the highest monthly mean flow for December since record-keeping began. Only the Savage and Youghiogheny Rivers in western Maryland were at normal levels.

Since the region recovered from the drought last winter, water levels in most of these streams and wells have been at above normal levels.

Streamflow

Three streams were at the highest December flows since the 1940s: Nanticoke River in Delaware, and Nassawango Creek and Pocomoke River in Maryland. Streamflow at most of the stations used to assess water conditions across Maryland and Delaware has been at above normal levels in December and for most of the year, although streams in western Maryland have dropped to the normal range. Five-year monthly streamflow hydrographs from the USGS stream-gaging network can be viewed on the USGS website at http://md.water.usgs.gov/surfacewater/streamflow/. Current and historical streamflow data can be monitored on the web at: http://waterdata.usgs.gov/.

Annual streamflow records were also broken. Six streams had the highest annual flows since record-keeping began (see table below). All streams had at least the fourth highest flow in 2003.

The Patuxent River in Maryland went from the lowest annual mean monthly flow in 2002 to the highest in 2003 since record-keeping began in 1944.

Daily streamflow on the Potomac River near Washington, D.C. in December averaged 22.1 bgd, which is about 3 times higher than normal December flow. The average flow for 2003 was 16.9 bgd, which is 55 percent above normal. More information on the Potomac River is available at: http://md.water.usgs.gov/monthly/poto.html.

Streamflow on the Potomac River (shown at left) has been above normal (triangles) for the entire month and for most of the year. Flood stage (green line) was reached on December 12, which was also a new record daily maximum.

Current streamflow, groundwater levels, and water-quality information for the Nation can be viewed on the USGS National Water Information System (NWIS) website: http://waterdata.usgs.gov/nwis

Groundwater-Unconfined or Shallow Aquifers

Ten of the 15 wells used by the USGS to monitor unconfined or shallow aquifer response to climatic conditions in the bi-state region were at their highest December levels in more than 40 years. Wells in Baltimore, Carroll, Charles, Harford, Prince Georges, and Queen Annes Counties, Maryland, and Kent County in Delaware reached the highest December level in 40 years. The remaining five wells were within about a foot of setting a December record high water level. This is the fourth consecutive month of record-setting high levels for wells in Harford, Queen Annes, and Prince Georges Counties. The well in Carroll County set new monthly record highs for 6 out of the last 12 months.

By last December, the region had recovered from the severe hydrologic drought of 2002. Water levels are expected to rise through the winter and spring months as groundwater resources are recharged. Recharge typically begins in October when most plants are dormant and temperatures are lower. This year, water levels are already at high levels typically seen during the winter and spring. Winter’s cold temperatures can cause the ground to freeze and recharge will subside until warmer temperatures and melting occurs in the spring.

5-year hydrograph shown to the right for a well in Harford County shows that the water level in the well, measured in depth below land surface, is at a record-setting high for December 2003 and has been for the last four consecutive months. The water level is close to the all-time record set in May 1998. Water levels recovered from the record-setting low during the 2002 drought a year ago, and have been above normal for the past 10 months. For 5-year hydrographs of groundwater levels for the climatic indicator wells, visit: http://md.water.usgs.gov/groundwater/.

Groundwater-Confined or Deep Aquifers

Although water is plentiful at the surface (streams, reservoirs, and shallow groundwater reserves are full), some of the deep confined aquifers used for water supply by many people living in southern and eastern Maryland continue to decline. The water levels continue to decline because they are being pumped more quickly than deep groundwater is recharged and since the confined aquifers are deep, water levels in confined aquifers take longer to respond to climatic conditions than shallow aquifers. Confined aquifer wells are measured monthly and can be viewed at http://md.water.usgs.gov/groundwater.

Reservoir Storage

High groundwater levels and above normal streamflow and rainfall helped to keep reservoir storage levels in the Baltimore reservoir system at capacity in December. Storage in the Triadelphia and Duckett Reservoirs on the Patuxent River has decreased to 95 percent of capacity because of releases to allow for spring runoff.

USGS Water Monitoring

Streamflow and groundwater levels are used to assess the current water conditions and can 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 regulation. For more information on streamflow and groundwater levels in Maryland, Delaware, and Washington, D.C., visit Water Watch at Water Watch.

Groundwater is an important component (in addition to streamflow and reservoir storage) in assessing water resources, however, as groundwater is usually hidden underground, it is difficult to know the status of aquifers in a timely manner. Most wells are measured by hand on a regular basis, commonly monthly. Real-time data collection offers many benefits. Real-time groundwater data are defined as data automatically collected, transmitted, and made available to the public at least once a day. These data can be transmitted by land-line telephone, cellular telephone, radio, satellite telemetry, or a combination of these technologies. The advantages of real-time data collection include timeliness, data quality, data availability, and cost. There are currently five wells in Maryland and one well in Delaware equipped with real-time data collection. Within the next year, several wells in Calvert County, Maryland will also be monitored in real-time. To view real-time groundwater levels, visit the USGS NWISWeb site at http://waterdata.usgs.gov/. Select groundwater from the data category, then real-time, then your region of interest, such as Maryland.

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, Baltimore County, Baltimore City, and other agencies. The observation wells used in this analysis are operated in cooperation with the Maryland and Delaware Geological Surveys. The real-time wells are operated in cooperation with the Maryland and Delaware Geological Surveys, the Interstate Commission on the Potomac River Basin, and Calvert County, Maryland. The USGS publishes data for 137 streamflow stations and 379 observation wells across Maryland and Delaware.

The USGS serves the Nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.

** * 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 Ground Water Levels Still Low
• 01-06-2000 1999 Flow Into Chesapeake Bay Lowest Since 1960s Drought