Visit the Williamson River Delta today—where the Williamson River enters Upper Klamath Lake, in Klamath County, Oregon—and you’ll find 5,500 acres of pristine wetlands, neighbored by 800 acres of thriving agriculture. Upper Klamath lake hosts nearly three million birds annually flying on the Pacific Flyway. The wetlands traditionally promote clean water by preventing excess nutrients from entering the lakes, they help eliminate weed seed sources to farm fields and they provide habitat for native fish and wildlife. This marshland has been helping to maintain the local ecosystem for thousands of years. But recently—for the past 50 years—it had mostly disappeared.

Changing Landscapes, Endangering Species

Shortnose and Lost River suckers, known to the Klamath Native Americans as Qapdo and C’waam, have been a primary food source for the Klamath and Modoc Tribes throughout history. And the Williamson River Delta is one of the most important nursery and rearing habitats for larval and juvenile suckers.

However, in the 1940s, levees were built to convert more than 7,000 acres of this historic marsh system to cropland and pasture, eliminating connectivity between the wetland ecosystem and the Williamson River, Upper Klamath Lake, and Agency Lake. The loss of the wetland habitat contributed to a severe decline in the fish populations, forcing the Native tribes to close their fishery in the 1980s. Continued declines in habitat and population caused the two sucker species to be listed as endangered species.

A Group Effort

The Williamson River Delta area was identified as a critical site for restoration in the 1990s, and The Nature Conservancy purchased the northern half of the delta in 1996 and the southern portion in 1999. TNC set out to restore the wetland with help from the Upper Klamath Basin Working Group, leaders from The Klamath Tribes, community leaders, federal, state and government agencies, local farmers, and PacifiCorp.

The Critical Restoration

One of the main goals of the restoration, aside from restoring the fish habitat, was to improve water quality in Upper Klamath and Agency Lakes. The group wanted to restore the leveed wetlands around Upper Klamath Lake, as they are critical to the larva life stage of suckers, and they help to reduce nutrient loading in the river and lake. An additional 800-acres remain in organic alfalfa farming providing food for migrating waterfowl in the fall and winter months and also help to provide job opportunities and revenue for the local communities.

A wetland restoration plan was created to reconnect the wetlands to Upper Klamath and Agency Lakes, and water levels in the wetlands are driven by lake level patterns. Native wetland species were planted, noxious weeds are being tracked and removed, organic alfalfa and grain are being produced in uplands, adjacent to restored wetlands, and native upland vegetation is being restored in non-agricultural uplands.

Restoration of the wetland ecosystem began in 2006. Levees were lowered and breached, using both explosives and mechanical equipment, inundating the delta within just a few short days.

Since then additional levees have been breached and channels evacuated and restored. Today approximately 5,500 acres have been flooded and restored.