The level trended all the way down to 60 feet below the surface by around 1971, a low point as major industry near downtown such as NCR and others reliably pulled large volumes of water year round from the Great Miami River aquifer.
But as industrial users left, starting in 1971 the groundwater level began to rise. By the mid-1980s, it rose to around 30 feet below the surface. At times since then, it’s spiked 10 feet higher.
Because some downtown buildings such as the Montgomery County administration building were built during the drawdown, they’re more vulnerable to flooding as the level has risen.
The rise means the ground has less deep absorbing capacity after heavy rains, so flooding can be more frequent. The county building, which has two underground levels, installed a dewatering well to cope.
Matthew Carpenter, deputy director of the city of Dayton Water Department, said the trend remains in place.
Checking city records, he found that in 2001, the city’s top 10 consumers used about 10.3 million gallons of water each day. By 2010, the top 10 consumers used 7.4 million gallons daily. In that time frame, the city lost two Delphi plants — Delphi Chassis North on Wagner Ford Road and Delphi Chassis Inland on Home Avenue — as well as a Chrysler plant. The three used about 2.6 million gallons daily in 2001. City water production in 2001 averaged 69.7 million gallons a day. In 2010, it had slid to 58.5 million gallons a day.
But close scrutiny of the monitoring well figures reveals the start of a new trend that could help drive the water level down again, said Mike Ekberg, manager of the water monitoring program at the Miami Conservancy District.
Greater use of geothermal systems that require large volumes of groundwater to heat or cool buildings seems to be keeping the water table in check. Ekberg gives new geothermal systems some credit for helping push groundwater levels down beginning a few years ago. The technology makes use of groundwater’s constant temperature of 55 degrees.
The city of Dayton last year studied the feasibility of forming a geothermal utility district. The study said more individual buildings could tap the huge water capacity of the aquifer for geothermal. Geothermal systems offer cost savings of up to 34 percent compared with conventional systems, according to the study from Heapy Engineering, Moody’s of Dayton and Western Solutions.
The study found that a third of 60 buildings in the Central Business District use geothermal. Buildings in or near the district include the Dayton Art Institute, the new CareSource Management Group headquarters, The Cannery loft apartment and retail complex, the Montgomery County Administration building and courts campus, the Sinclair Community College campus, and Miami Valley Hospital. The next stage is to get more businesses to invest in geothermal, said Timothy Downs, deputy director of economic development for the city. The city has set aside $1 million in incentives, funded by a Dayton Power & Light contribution, for businesses that want to install geothermal.
More information on the City Hall groundwater well can be found here: www.dnr.state.oh.us/water/waterobs/wellinfo.asp?wellid=MT-6.
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