The Bateman Island causeway will have to be breached to aid migration of fish between the Columbia and Yakima rivers, researchers say.
The Benton Conservation District and the nonprofit Mid-Columbia Fisheries Management Group are looking at creating holes in the 74-year-old, 500-foot-long causeway.
How large the breach should be is still uncertain, said Rachel Little, outreach coordinator for the conservation district.
"It could look like a bridge, it could look like a culvert," she said. "It could be one long bridge, it could be two short bridges."
The groups want to get feedback from the community, so they have scheduled two meetings next week at the Mid-Columbia Libraries Union Street branch in Kennewick. The first meeting is at 6:30 p.m. Tuesday, with the second at 10 a.m. Friday.
"We're really trying to get the public engaged so they can direct us through the process," Little said.
The earthen causeway, which connects the island to the riverfront trail in Richland, acts as a dam. It divides warm water flowing from the Yakima to the west from the cool water of the Columbia to the east. The water to the west of Bateman Island tends to back up and stagnate in the sun.
The super-heated water at the Yakima River delta serves as a barrier to young salmon migrating downstream to the ocean and adult fish coming up the Columbia, Little said. It also attracts predators such as bass and catfish.
Creating holes would cool the water on the west side of the land bridge, according to preliminary results from computer modeling by Intera Inc. of Richland.
The conservation district and the fisheries management group hope to have a preliminary design for opening the causeway by June 2015, Little said.
Cost is an issue that would have to be considered, because a 500-foot bridge would be very expensive, Little said.
The impact on recreational use also needs to be considered -- the cove to the east of the causeway is a popular summer hangout for boating and fishing.
Modifying the causeway will also require approval from agencies including the Army Corps of Engineers, which owns Bateman Island and the shoreline, the state Department of Natural Resources, which owns the water, and the state Ecology and Fish and Wildlife departments, said Rebecca Wassell, Yakima Basin program manager for the fisheries enhancement group.
In addition, officials will have to ensure endangered species and cultural resources are protected. Native American remains have been discovered on the island, which is also near where the Lewis and Clark expedition traveled farthest up the Columbia.
Wassell expects the approval process to to go smoothly, because they have been working closely with the regulatory agencies, she said. It could still take two to three years to start construction on the project after a preliminary design is approved.
Amy Ford, owner of the Columbia Park Marina, said she will attend the meetings to see what breaching the causeway would mean for her business, which is near the cove it creates. She wants to see how the water current will be affected.
"It will definitely affect us some, but I can't really comment how at this point," she said.
Wassell hopes the meetings will result in the formation of a committee, composed of regulators, engineers, wakeboarders, fisherman and the public, she said.
"We want to work with all the stakeholders as we discuss the modifications," she said.
The city of Richland leases Bateman Island from the Corps of Engineers for recreational use, Little said. But who owns the causeway is less certain.
The process of studying the causeway revealed that the Corps does not actually own it, said Bruce Henrickson, spokesman for the Corps Walla Walla district.
The deed transferring ownership of the island from the Bateman family to the Corps does not specify who owns the causeway, meaning it has no clear title holder, Little said. The closest thing to an owner is the Department of Natural Resources, because it owns the river bed.
"The state of Washington is looking at whether it can be considered an illegal abandoned structure and removed that way," she said.
-- Geoff Folsom: 509-582-1543; firstname.lastname@example.org; Twitter: @GeoffFolsom