WASHINGTON – When Maryland officials tried to determine the severity of last year’s drought they looked at rainfall, reservoir levels, stream-flow data — and groundwater levels that could be as much as a month out of date.
That could change with satellite-linked well-reading equipment that is being installed on wells around the Potomac River basin, including four wells in Maryland. The new monitors will provide hourly measurements that researchers say will help the state make better drought management decisions.
“It was not sufficient to have readings just once a month” during critical months of the drought, said Jim Gerhart, district chief for the U.S. Geological Survey in Maryland, Delaware and Washington, D.C.
Groundwater is the “water than you can’t see but which is critical to understanding how much water you actually have,” said Lisa Wright, spokeswoman for Rep. Roscoe Bartlett, R-Frederick, who helped secure funding for a study of groundwater in the Potomac River basin.
The availability of real-time data about groundwater has long-term implications, too, Wright said. In the long term, the data will give planners the ability to make wiser decisions about development.
So far, researchers have equipped 15 of the hundreds of existing monitoring wells in the basin with devices that use satellite telemetry to transmit data. The four in Maryland include one each in Washington and Allegany counties and two in Frederick County.
The USGS hopes to equip 20 to 30 wells in the basin with the technology.
“It would be overkill to have that in all the hundreds of wells that we have,” Gerhart said.
Because water is absorbed into the ground differently, depending on the land area, Gerhart said the equipped wells will be located in different geographical areas of Maryland, such as limestone settings or mountainous, rocky settings.
“What we need to do is make sure that we have a good representation of all the settings in the basin,” said Gerhart.
The Potomac Basin, also known as the Potomac watershed, stretches nearly 14,670 square miles across Virginia, Maryland, West Virginia and Pennsylvania. In Maryland, the basin spans 3,818 square miles.
Claire Welty, a hydrologist and professor of civil and environmental engineering at the University of Maryland Baltimore County, is not involved in the project to bring real-time groundwater data to researchers. But she said it should help them better understand the relationship between groundwater and surface water.
For example, real-time data could help hydrologists predict groundwater flow to rivers, she said.
And even though groundwater moves much more slowly than surface water — in terms of feet per year and not feet per second — Welty said it would be useful to have groundwater levels measured at roughly the same frequency as surface water levels.
Monthly monitoring lets hydrologists predict upward and downward trends over time, but provides little data about the times in between these ups and downs.
“I would be very happy because you can just tell much more about the dynamics of this system,” she said.