Benton County wants to withdraw from the group seeking solutions to nitrate pollution in private drinking-water wells in the Lower Yakima Valley’s unincorporated area.

The county’s request, submitted earlier this month to the state Department of Ecology, indicates the county will try to create its own Lower Valley Groundwater Management Area (GWMA) to deal with pollution in parts of Benton County that are outside the existing area’s boundary.

The management area, created in 2011, covers south of Union Gap to Benton City in Benton County. The Yakama Indian Reservation is not included in the 512 square-mile management area.

Also of concern is that Benton County has three members on the 22-member advisory committee, but has 45 percent of the land base, representatives said.

The advisory committee includes county elected officials, other local, state and federal agencies, agriculture and irrigation representatives and private citizens.

Benton Conservation District Manager Mark Nielson, a member of the advisory group, said the decision grew out of discussions within the county.

“The initial question was do we think this is a positive thing for Benton County citizens?” Nielson said Monday. “Again, we think we have been doing things and can do things in the future that would be beneficial.”

Ecology Department officials have acknowledged receiving the request and want to talk to Yakima County, which is the lead agency for the management area. Benton County would have to apply and receive approval from Ecology Director Maia Bellon to form a new management area.

Yakima County Commissioner Rand Elliott said he wants to talk to his counterpart, Benton County Commissioner Jerome Delvin, to learn more about the county’s decision.

“This has been a difficult process to get going with a lot of hurdles to get over,” Elliott said. “We have fought our way through that and are starting to make progress.”

Delvin was not available for comment Monday.

The advisory committee recently adopted a work plan that includes identifying problems and steps to reduce pollution, monitoring, public education and development of public drinking-water systems. The management area has received $750,000 in state grants to develop and implement the program.

Yakima County sought to form the management area in response to sampling that found more than 20 percent of Lower Valley wells exceed the federal drinking-water standard for nitrates. The contaminant, which can come from a variety of sources, can be harmful to infants, the elderly and those with compromised immune systems.

Some sources are manure from large animal feeding operations, application of nitrate fertilizers and failing septic tanks.

Rick Dawson, a Benton-Franklin Health District representative on the advisory board, said tests have shown high nitrate levels in wells east and south of the management area boundary in Benton County.

Nielson, who provides staff support to the 16-year-old Columbia Basin Groundwater Management area, said the advisory group is made up entirely of citizens with no agency voting representation. The management area covers Franklin, Grant, Adams and Lincoln counties and works on both groundwater quality and quantity.

“At the end of the day, if you want to affect groundwater quality, you need to bring on board those people who have to implement solutions on the ground in their backyards and fields,” he said.

Elliott said the GWMA structure doesn’t have any authority to make changes, but can make recommendations to agencies and governments that would implement them. He said Benton County could apply measures the advisory group develops any place in the county.

“They can take what we come up with and use it,” he said.

David Lester can be reached at 509-577-7674 or dlester@yakimaherald.com.