Kennewick will be experimenting with a novel way of making sure the city has enough water to meet peak demand during the summer months.
The $4 million project involves using an existing aquifer in the Southridge area to store water removed from the Columbia River during the winter when water is plentiful.
Construction is expected to go to bid in the next month, said Evelyn Lusignan, Kennewick customer service manager. It should be finished in early 2014.
Aquifer storage and recovery can help provide water for future growth while keeping more water in the Columbia River and other rivers during critical times, said Bruce Beauchene, Kennewick city engineer. It benefits the environment by keeping water in the river when fish need it.
It also is a way for the state Department of Ecology to try to create new water rights. Derek Sandison, director of Ecology's Office of Columbia River, said that because more water can't be created, timing is a key option. Water will be removed when it is abundant, stored and then used when water is limited.
"The aquifer storage approach seems to be very promising," he said.
It's a way for Kennewick to bank water it has a right to but isn't using in the winter, Sandison said.
It appears to be a relatively inexpensive way to store water, he said, and it doesn't have the water quality and space issues that above-ground storage does.
Ecology is working on similar pilot projects with Boise Cascade in Wallula and the city of White Salmon, Sandison said.
Kennewick will be giving Ecology officials information on the process, as well as testing once the project is complete to help determine the impact on the aquifer, any water loss, mixing of the groundwater and treated river water and the cost of operating the system, Beauchene said.
The aquifer, which is part of the Wanapum aquifer, is near Southridge High School.
While the city doesn't have any water rights that allow it to pump from that aquifer, it can use it to store water that it does have the right to use under the so-called quad-cities water right it shares with Pasco, Richland and West Richland, Beauchene said.
More water is available in the Columbia River during the winter months from snowmelt and runoff.
That's when Kennewick will pull water from the river and the city's groundwater well in Columbia Park, treat it to drinking water standards at its drinking water treatment plan, then store it in the aquifer, Beauchene said.
Because the river water is entering the city's distribution system, it must be treated to drinking water standards, Beauchene said.
When the availability of river water is down during the summer, the city then will pull the water out of the aquifer, treat it with chlorine, and it will be used in the Southridge and Canyon Lakes area, Beauchene said.
Maintaining safe drinking water is the first priority for Kennewick, he said.
Using an existing aquifer is less expensive and more secure than building storage, Beauchene said.
"We are using what has naturally been constructed to store this water," he said.
Each day, the city will pump 3 million gallons of water into the aquifer, he said. The amount of water will depend on how the project goes, and whether pumping lasts for a 30-day or 60-day period.
Building a reservoir that large just is not feasible, Beauchene said.
Being underground also helps protect the water from animals and contaminants, he said.
The project is a key part of the expansion in the Southridge area, Beauchene said.
Work on a pump station will allow the saved river water to be used for the 1,263 acres south of Interstate 82 and west of Highway 395 that Kennewick has asked Benton County to add to its urban growth area for future industrial projects.
This aquifer also is a potential emergency source of water for the city, Beauchene said. Kennewick is working with the state to get a permit to use the aquifer water in an emergency.
The city is getting ready to drill a monitoring well at the site that will be used to pull samples for testing, Beauchene said.
A wellhouse will be built with a vertical turbine pump to access the aquifer, Beauchene said. It will connect with the city's water piping system.
Ecology officials have committed to paying about $2.4 million of the $4 million project. The rest will come from city water revenues, Beauchene said.
The aquifer storage project is among those supported by money from the 2006 Columbia River water supply development program, Sandison said.
Part of the requirement for developing new water supplies through storage project is for one-third of the water to go back to the river to support flows, Sandison said.
That might happen naturally, with water moving from the aquifer into the river, he said. That is one of the things to be tested with the pilot project. If that does not work, a direct release of water into the river would need to happen.