Beyond the tap - Part 2 of 3

By Sarah Watson

Published: July 27, 2008

Hundreds of feet below Central Virginia, waves and ripples are frozen in ancient rock.

The rock may seem solid, but countless gallons of water flow through fractures that have formed as continents drift.

The water is tapped by wells throughout the region, supplying thousands of homes not served by public water utilities.

In some areas, and especially since the 2002 drought, that water is becoming harder to find. Well drillers are receiving more emergency calls from homeowners whose wells are drying up. Drillers have to dig deeper to find reliable water.

Beyond the Tap: Online Resources

Just how much water flows beneath the surface in Virginia — and how its reliability is affected by weather patterns and development, among other factors — is the subject of an ambitious state study now under way.

The first phase is a comprehensive database detailing every existing Virginia well on record. The next steps include analyzing existing information on state-wide groundwater resources. That could take several years.

“There’s a common misconception held by the general public that there is and will always be plenty of good groundwater available for whatever use that anybody wants,” said Scott Bruce, program manager with the Department of Environmental Quality’s office of groundwater characterization.

“Unfortunately, that’s not the case. We are dealing with a finite system. The general perception needs to be changed to understand that we’re not (ground) water rich.”

While the groundwater study is a statewide project, the information is of particular interest in our section of the Piedmont, where subsurface rock stores less water than in other areas.

Most envision groundwater as a series of unseen rivers and lakes hundreds of feet below the surface. In reality, water fills in spaces between cracks and crevices, also called an aquifer.

Certain types of bedrock, such as that in Florida, Texas and the Shenandoah Valley, have more spaces and cracks than others, making wells much more productive. That’s not the case in our section of the Piedmont, where water only flows through small fractures in dense, hard ancient rock.

The region’s wells produce only a fraction of what those in the eastern portions of the state yield, DEQ groundwater geologist Brad White said. In the coastal plain — generally any area east of Interstate 95 — billions of gallons flow through sand grains and fossilized shells.

Wells there can produce 1,000 gallons per minute, whereas in the Piedmont a well producing 150 gallons per minute is rare, Bruce said.

“Unfortunately, in the hard rock portions of the state, there’s very little storage in the fracture rock system,” he said.

The office that Bruce heads was recently formed as part of a General Assembly response to the 2002 drought, which left streams at near-record lows and many shallow wells dry.

The four-person staff embarked on an ambitious plan in 2006 that will eventually result in a comprehensive study of the state’s groundwater resources, Bruce said.

The study looks at how to describe local groundwater quantity to “hopefully get a better understanding of what areas, geologically speaking, are more conducive to higher yield wells,” White said.

“Where is the water and what’s the role geology plays in it? And if there’s no water, why is that? That’s just equally as important.”

Groundwater levels are influenced by more than just rainfall. One key factor — which the state study will try to grasp — is how many people pull water from the same veins. Several municipal wells in the town of Appomattox, for example, tap the same fracture, White said.

There is no statewide database to show the location or the yield of every well in Virginia. Rather, well information is kept by several agencies that issue permits, including the state health department, the DEQ and the United States Geological Survey. That information is sometimes incomplete and only as good as what was provided by the driller, White said.

Also, some private wells dug before 1992 didn’t need permits, so the state doesn’t have a firm grasp on exactly how many straws are sucking water out of the ground, Bruce said. “Nor will we ever.”

In our region there are about 300 wells that each supply more than 300,000 gallons per month. That figure does not include wells serving private residences or users pulling out less than 300,000 gallons per month. Those living in Concord and Appomattox all are supplied by well water, including the 1,700 residents of the town of Appomattox.

It’s not just additional wells from increased development that can put a strain on groundwater resources. The added pavement — from driveways to buildings to parking lots — also is thought to affect the water table. That’s especially true when the development covers what is known as a “recharge zone,” or an area where rain and melting snow seep into the ground and supply deeper fractures.

Falwell Corp. has been drilling wells in Central Virginia since the 1930s. Since about 2000, vice president Charles Falwell said he and his drillers have noticed changes in groundwater.

Falwell said his company has seen a recent drop in drilling wells for new residential construction because home sales are down, but he has seen a marked increase in emergency calls because older wells are going dry.

Property owners previously could get productive wells that were less than 250 feet deep. Now, the drillers often go to 400 feet before they can find enough water, Falwell said.

He attributes much of that problem to another key factor affecting groundwater — the weather.

The Southeast has been in a drought off and on since the late 1990s. Despite the occasional soggy year, Lynchburg’s rainfall has been below average seven of the last 10 years.

In 2002, the reporting station at the Lynchburg airport was 6.42 inches below normal; 2007 ended 6.53 inches below normal and so far this year, amounts are about 8 inches below normal. This time last year, the area was only about two inches below normal.

Combined with warmer weather throughout the year which speeds evaporation, that contributes to lower groundwater levels.

“It’s worse each summer season,” Falwell said. “The biggest problem is we just haven’t had the snow.”

Snow is the best way to replenish the water table because as it melts, the water seeps into the ground rather than rushing off as it does during thunderstorms, Falwell said.

“We get these big thunderstorms and 90 percent of the water runs off and doesn’t soak into the ground,” he said.

“It’s good for lakes, but it’s not worth a heck for the aquifer.”