Great Lakes Article:

Wisconsin takes water storage underground

New aquifer rules may save Wisconsin communities millions

By DON BEHM
Milwaukee Journal Sentinel staff

Last Updated: Aug. 17, 2002

Wisconsin communities have been given a green light to save millions of dollars by storing treated drinking water deep underground.

Pumping clean water down wells during winter and spring will enable municipalities to retrieve it quickly in summer to slake thirsts and refresh vegetable gardens.

Below-ground storage also will enable communities to postpone costly water treatment plant expansions or investments in new water sources that otherwise would be needed to meet heavy demand during hot months, local and state officials said.

Oak Creek will be the first community in Wisconsin to take advantage of the technology, known as aquifer storage recovery, now that the state Natural Resources Board last week approved rules regulating the systems. The city's potential savings: $5 million in the next three to four years.

"The more wells we can use for storage, the more money we can save in future plant expansions," said Dan Duchniak, assistant general manager of the city's Water and Sewer Utility.

Green Bay and nine other Brown County communities also are considering pumping treated water into deep aquifers at a savings of tens of millions of dollars.

"Wednesday was a huge step forward for using this technology," said Bill Nabak, general manager of the Green Bay Water Utility.

Green Bay is trying to persuade the nine suburbs to buy treated Lake Michigan water from it. They would pay $37 million to connect to the city - nearly $100 million less than it would cost them to build their own water treatment plant and pipeline to the lake.

Waukesha, too, is seriously studying such a storage system because the rapidly growing city knows it will need to more than double its water capacity in the next 20 years, just to quench average daily demand.

"We are looking for new water supplies, and we need to look at new storage technologies," said Jeff Detro, acting general manager of the city's Water Utility.

Had backed away

Although 14 other states, beginning with New Jersey in 1968, have authorized the technology, Wisconsin regulators had backed away, citing concerns over groundwater contamination.

Tests at an Oak Creek well since 1999 have convinced Department of Natural Resources officials and legislators that such systems could operate without harming the environment.

Oak Creek found that pre-chlorinated water stored underground for several months remained clean enough to drink, meeting all state and federal standards. As important, levels of chlorine byproducts in the stored water gradually declined, and groundwater quality was not degraded.

Such tests, as part of a pilot study, will be required for all communities applying for aquifer storage recovery permits, said Jill Jonas, director of the DNR's bureau of drinking water and groundwater in Madison. The tests are needed to protect public health and groundwater quality, she said.

Prior to approval of an operating system, communities also will need to show that they have taken steps to conserve water.

Conservation requirements will ensure that communities use water resources as efficiently as possible, Jonas said.

Now that the Natural Resources Board has approved guidelines for using the storage technology, the DNR must complete one last step that will make the technology more feasible, officials said.

The Legislature, in the recent state budget repair bill signed by Gov. Scott McCallum, approved a key exemption in groundwater law. Although stored water meets drinking requirements, state groundwater protection standards are more strict.

Consequently, tests of stored water at an aquifer storage well site could show that chlorine byproduct concentrations exceed groundwater limits. The Legislature's budget repair bill relaxed the law, allowing municipalities to exceed those limits up to a distance of 1,200 feet or the nearest private well. The extra distance from the storage well will ensure the byproducts are diluted in groundwater.

Jonas and DNR officials say it will take them six months to amend the regulation and bring it in line with the change in state law.

Communities can apply for pilot projects in the meantime, because it will take longer than six months to get them approved, said Oak Creek's Duchniak.

Well at local park

The Oak Creek well selected for the state's first aquifer storage study is at a city park and extends about 1,800 feet deep into a sandstone aquifer.

"We've been through two full cycles, pumping 42 million gallons down to the aquifer and recovering it, and we've had no complaints from our customers," Duchniak said.

"I believe we will move forward now, from our experimental status to an operating system," he said.

Oak Creek now draws all of its drinking water from Lake Michigan. The utility also serves Franklin residents. By 2020, Oak Creek plans to boost its dependency on storage aquifers, withdrawing up to 8 million gallons of stored water a day in summer to meet peak demand, he said.

The most ambitious aquifer storage project being discussed, however, is in Brown County.

The key to state approval there is whether future tests of Green Bay's pilot well find that health-threatening amounts of arsenic are not being released from bedrock into the stored water, said Nabak.

"If we go to the lake on our own and build a $135 million system, we'd still use aquifer storage for future expansion," said Len Teresinski, president of the Village of Hobart and president of the nine-community Central Brown County Water Authority.

"If we go with Green Bay for our supply, we'd still need six storage wells to begin with and a total of 10 storage wells by 2010."

Final cost estimates are expected next week, Teresinski said. The authority could make its decision by late September. The other communities in the authority are: City of De Pere; villages of Howard, Ashwaubenon and Allouez; and towns of Scott, Lawrence, Ledgeview and Bellevue.