The Garber-Wellington aquifer provides a strong component of water needs for approximately 1.2 million people as estimated in the 2010 census. That population is expected to increase by 20 percent from 2000 to 2030, according to the report.
The study was done to determine how that growing population’s draw on the groundwater supply would affect the long-term aquifer storage. To answer that question and provide information that could result in strategic state policy, the USGS investigated the hydrogeology and simulated groundwater flow in the aquifer using a numerical groundwater-flow model.
“A multiple-well aquifer test was completed at a production well near Norman as part of this report to determine transmissivity and a storage coefficient for the central Oklahoma aquifer,” the report states. “Water levels were measured in 280 wells as part of this investigation between Feb. 17, 2009, and March 13, 2009.”
While the Garber-Wellington aquifer is not sustainable at the current level of allowed withdrawal, predictions for the future are better than expected.
Komiske anticipates revised withdrawal allowances will be somewhere between 1.1 and 1.5 acre-feet per acre per year. The model used in the study indicates these amounts could be sustainable for 50 years.
The model isn’t intended to be perfect, Komiske said, but provides a scenario for making predictions. For Norman, things are looking good for future well water supplies.
“Norman has the right to a lot of property because as subdivisions go through the platting process and expect the city to provide water, they give us their water rights,” Komiske said.
Norman will likely be able to bring new wells online as needed in developing areas, provided the funding is available. However, how future Environmental Protection Agency regulations regarding naturally occurring pollutants will affect the well water supply is yet to be determined.
Currently, Norman is investigating potential treatment to eliminate or reduce arsenic and chromium 6, should the need arise.