Monday, February 12, 2018

Groundwater is Limited

The U.S. Geological Survey released a report-USGS Professional Paper 1829 titled “Assessment of groundwater availability in the Northern Atlantic Coastal Plain aquifer system From Long Island, New York, to North Carolina.” According to John Masterson, a USGS hydrologist and lead author of Professional Paper 1829, in the southern part of the Atlantic Coastal Plain aquifer depletion of the groundwater aquifer, sustainability, is the biggest concern.

In the Virginia Coastal Plain the aquifers used for drinking-water supply typically are deep and not well connected to land surface. Pumping in this area therefore does not have a large effect on surface waters; however, the restricted connections between the deep aquifer and surface waters has lead to groundwater depletion. Although only 14 % of the total pumping from all aquifers in the Northern Atlantic Coastal Plain occurs in Virginia and North Carolina, it accounts for almost half of the total groundwater depletion in the entire aquifer system.

“In this area, most of the pumping occurs in the deep confined aquifers that are not well-connected to land surface and the water pumped from these wells isn’t groundwater that otherwise would have discharged to streams or to coastal estuaries,” said Masterson.

According to the USGS report groundwater depletion in the Virginia Coastal Plain is a real concern. As the aquifer is depleted the USGS expects the land to subside. This would cause the gradual lowering of the land surface in the Coastal Plain and would intensify the effects of local sea-level rise, particularly in the Lower Chesapeake Bay area in southern Virginia. In addition, in coastal areas, groundwater depletion can result in the landward encroachment of salty groundwater, diminishing the quality of the drinking water in this region.

In places like Long Island and New Jersey, also part of the Atlantic Coastal Plain aquifer, groundwater depletion is not a serious concern. There, shallow aquifers used for drinking-water supply are well connected to the land surface and easily replenished by rainwater that seeps into the ground as aquifer recharge. However, although there appears to be plenty of water available, removing any of it from the aquifer reduces the freshwater needed to keep streams flowing and support the marine life that depend on fresh groundwater discharge to coastal estuaries. According to John Masterson, “Pumping these wells captures the groundwater that otherwise would have become streamflow or gone to the estuaries. Reducing flows from aquifers to these surface waters, can result in adverse ecological effects.”

The U.S. Geological Survey (USGS) began studying groundwater availability in the Atlantic Coastal Plain aquifer system in 2010. This is part of its ongoing regional assessments of groundwater availability of the principal aquifers of the Nation. Smaller aquifers essential to the viability of many communities are not being studied. Over 30% of Virginia is reliant on groundwater for its drinking water supply more than half of them in smaller aquifer systems. Virginia is dependent on groundwater.


Increases in population and changes in land use during the past 100 years have resulted in increased demand for freshwater throughout the Commonwealth with groundwater serving as a vital source of drinking water for nearly 1.5 million people . According to the USGS water levels in many of the confined aquifers are decreasing by as much as 2 feet per year in response to extensive development that may have impacted recharge and increased groundwater withdrawals to supply growing population. Total water-level drawdowns are more than 100 feet in the Atlantic Coastal Plain aquifer from their predevelopment (before 1900) level. Water resources must be managed beginning with the local planning for land use and development. 

There are already problems with availability, quality and sustainability of groundwater in Virginia in places such as Fauquier County, Loudoun County in addition to the Atlantic Coastal Plain. In the 21st Century it is now possible for NASA to measure groundwater depletion from space using their satellites. NASA found that over the first ten years (2003-2013) of data that they tracked all of Virginia’s groundwater aquifers were being depleted, using groundwater faster than it was being recharged.

No comments:

Post a Comment