BPA helps restore floodplain habitat in the lower Columbia River estuary

The roar of engines can be heard near Burlington, Oregon, where large tractors are delicately shaping the earth to improve marshland along the Multnomah Channel, critical habitat for salmon and steelhead.

The work crews and their tractors scrape between 2 to 3 feet of dirt off the top of the wetland to control invasive plants, such as reed canary grass. Lowering the floodplain also keeps the ground wetter for longer periods throughout the year. Scientists say that’s important because higher water levels promote native plants, such as wapato and bull rush.

“By lowering the landscape we not only get rid of invasive plants, but the water is deeper and stays around longer. That gives young salmon and steelhead a backwater to rest, eat and hide from predators,” says Tom Josephson, senior habitat restoration project manager for the Columbia River Estuary Study Taskforce (CREST).

The four and one-half acre site is called the Enyarts-McCarthy Creek restoration project. It’s one of three BPA funded fish and wildlife habitat sites CREST has restored in 2019. The others are the South Bachelor Island project near Ridgefield, Washington, and the Government Island project in the Columbia River near east Portland’s Glenn Jackson Bridge.

The Government Island project reconnects 289 acres of off-channel habitat to the Columbia River also helping young salmon and steelhead. Owned by the Port of Portland, Government Island is approximately 2,000 acres of natural area with a significant amount of land set aside for recreation.

This fall on the island work crews removed a large metal water-control structure, an old dock and 35 pilings to completely restore fish passage at the site. Once the barriers were removed, more work was invested to help restore the wetland and allow Columbia River tidewaters to once again inundate the area.

Biologists say more off-channel habitat for migrating fish is needed in the lower estuary, especially in the Portland-metro area where industry dominates much of the floodplain. The estuary stretches from Bonneville Dam to the mouth of the Columbia and is important for young migrating fish as they transition from fresh to saltwater.

Since 2007, BPA and its partners such as CREST have restored, reconnected or improved more than 14,000 acres of Columbia River estuary floodplain. That equates to approximately 51 miles of shoreline. Healthy marshland is not only critical for endangered Columbia and Snake river salmon and steelhead but also for other types of fish and wildlife. BPA Project Manager for these projects, Anne Creason, says “CREST is a strong project sponsor and has done an excellent job over the last 10 years in restoring essential habitat in the Columbia River Estuary for juvenile salmon to rest and grow.”