Vernita Bar (map) is a prolific spawning site for fall Chinook salmon in the Columbia River in Washington. The bar is on the north shore of the river a few hundred yards downstream of Priest Rapids Dam, at the upper end of the last free-flowing stretch of the Columbia in the United States, the 50-mile-long Hanford Reach.

Because of its location near the dam, the bar is susceptible to river-level fluctuations that result from dam operations — not just at Priest Rapids but at all the dams upstream as far as Grand Coulee. Priest Rapids is a run-of-the-river dam, which means it normally operates with a full or nearly full reservoir and provides minimal flow augmentation, at best. Most of the time, water that flows into the reservoir of a run-of-the-river dam has to be passed through the dam, unlike larger dams — Grand Coulee, for example — that are built for flood control and water storage.

At Priest Rapids, the last of a string of seven Columbia dams in central Washington, upstream dam operations sometimes cause rapid fluctuations in the river level below the dam in the Hanford Reach. When these fluctuations occur in the fall, after salmon lay their eggs in the Vernita Bar gravel, the receding water can uncover the eggs and cause them to dry out and die. When these fluctuations occur in the spring, after the salmon have hatched, the fingerlings can be stranded along the shore as the water recedes. Five of the seven mid-Columbia dams are owned and operated by public utility districts. In order moving upriver, they are Priest Rapids and Wanapum dams, owned by the Grant County Public Utility District, Rock Island and Rocky Reach dams, owned and operated by the Chelan County Public Utility District, and Wells Dam, owned and operated by the Douglas County Public Utility District. Above these are Chief Joseph Dam, operated by the U.S. Army Corps of Engineers, and Grand Coulee, operated by the U.S. Bureau of Reclamation.

To address the impacts of flow fluctuations on Hanford Reach salmon and to improve coordination of river and dam operations, in October 1979 the three mid-Columbia PUDs completed an agreement with the Federal Energy Regulatory Commission, which licenses the five PUD dams, regarding outflows from dams upstream of Priest Rapids to benefit Hanford Reach juvenile salmon and steelhead when they migrate to the ocean. The agreement, known as the Mid-Columbia Proceeding (FERC Docket No. E-9569), resulted from a complaint that was filed in 1976 with the Federal Energy Regulatory Commission by the Washington Department of Fisheries. The complaint against the three mid-Columbia PUDs sought minimum flow requirements at the five PUD dams (the dams are licensed by FERC). Washington later was joined in the complaint by the Oregon Department of Fish and Wildlife, the National Marine Fisheries Service and several Indian tribes.

A contributing factor in the complaint was a test period of low flows in the Hanford Reach below Priest Rapids Dam six months earlier, in April 1979, which were requested by the Washington Public Power Supply system in order to test water intake structures for its Columbia Generating Station nuclear power plant. The low flows killed a number of juvenile fall Chinook salmon in the Reach. In their complaint (FERC mid-Columbia Proceeding, Docket # E-9569), the fish agencies and tribes asked for stabilized flows to aid fall Chinook spawning in the Reach. Stabilized flows would keep the egg nests, or redds, covered with water. The then-current practice of ramping flows up and down from Priest Rapids Dam often left the redds exposed, causing the eggs to die.

The 1979 agreement, which was approved by FERC in 1980, included two parts — the Vernita Settlement Agreement and the Mid-Columbia Settlement Agreement. The Vernita agreement called for a four-year study of fall Chinook spawning at Vernita Bar, and the mid-Columbia agreement authorized five years of study to measure the effects of the dams on downstream-migrating juvenile salmon and steelhead.

In the interim, the mid-Columbia agreement authorized spilling 10 percent of the river flow at each dam during that period of the spring when the majority of the fish were known to be migrating. This spill program began in the spring of 1980. It was the first formal application of spill to pass juvenile fish at dams in the Columbia River Basin.

The 1979 settlement established the study and testing program, which continued through 1984. Based on the results of the study, Grant PUD designed a fish-protection program and began to implement it in 1984. After four years of successful implementation, the final Vernita Bar Agreement was signed in June 1988.

The agreement was signed by Grant, Chelan and Douglas PUDs, and by the Bonneville Power Administration, National Marine Fisheries Service, Washington Department of Fisheries, Oregon Department of Fish and Wildlife and the Yakama, Umatilla and Colville tribes. The agreement, technically an Offer Of Settlement regarding a dispute between Grant PUD, the Washington Department of Fisheries and others, was negotiated among the parties and offered to the Federal Energy Regulatory Commission.

In the Vernita Bar Agreement, the mid-Columbia PUDs and Bonneville agree to maintain a minimum outflow from Priest Rapids of 70,000 cubic feet per second, which would provide a maximum river elevation in the Reach for the fish and, hence, a guaranteed amount of spawning habitat in the river. According to the Agreement, “the goal during the Spawning Period is to limit spawning to the area below the 70 KCFS elevation on Vernita Bar.” The spawning period was defined as “the initiation of spawning and continuing until 2400 hours on the last Sunday prior to Thanksgiving.”

The Vernita Bar Agreement remains in effect as long as Grant PUD holds the joint license for Priest Rapids and Wanapum dams.