Last day to walk onto Richland’s Bateman Island set. Causeway coming out

The last day to walk onto Bateman Island at the confluence of the Yakima and Columbia rivers in Richland will be Dec. 21, the U.S. Army Corps of Engineers announced Tuesday.

The project to tear out the 500-foot-long causeway that allows people to reach the island on foot starts Dec. 22.

The island, with a 2.8-mile trail, is popular for fishing, walking, mountain biking and bird watching.

Contractors will start work by installing safety fencing and doing site preparation work. Excavation of the earthen walkway is expected to begin Jan. 5.

The Army Corps of Engineers — in partnership with Washington state agencies, the Yakama Nation and the Mid-Columbia Fisheries Enhancement Group — awarded a $1.2 million contract to Pipkin Inc. to remove the causeway.

The causeway, built in the 1940s, allows easy access to the island at the confluence of the Yakima and Columbia rivers, but it also restricts the water flow near the Richland Wye, raising water temperatures and degrading the river’s water quality.

The Army Corps of Engineers is having the causeway demolished to improve habitat for salmon.

As water backs up on the south and west side of Bateman Island behind the causeway, summer water temperatures can be as high as 86 degrees for sustained periods and 90 degrees at times.

The warm water creates ideal conditions for non-native fish, such as smallmouth bass, that prey with voracious appetites on young salmon migrating to the ocean in the spring.

It promotes algal blooms and provides a breeding ground for mosquitoes.

It also may prevent salmon returning from the ocean from entering the warmer Yakima River to spawn.