The HCP presents serious problems for Whychus Creek
Part 4 as we dive into U.S. Fish & Wildlife Service’s conservation plan for the Deschutes River Basin.
Three Sisters Irrigation District (TSID) has piped most of its canals and possesses the modernized infrastructure needed to manage water with control and precision. Despite this large public investment in its water management systems, TSID fails to meet the needs of fish and wildlife in Whychus Creek.
In the Habitat Conservation Plan (HCP), TSID commits to maintain 31.18 cfs of 1895 water rights instream below its diversion. The instream rights have a priority date equal to that of TSID’s irrigation rights. However, under state law, water is shared proportionally whenever the natural flow upstream of the diversion is insufficient to meet all rights. This happens every summer! When this seasonal shortfall occurs, it results in water rights regulation and instream flow reduction.
Maintaining 31.18 cfs is only a commitment on paper and not actual water in the creek.
Steelhead salmon
Not only do flows in the creek suffer from the regulation of the water rights, but streamflows are also further reduced through seepage to the ground. By the time the creek gets to Sisters, what was 20 cfs instream at the TSID diversion has been reduced to approximately 12 cfs. The creek experiences these low flows every year, beginning in July or August, depending on the water year.
Lethal conditions for fish
The HCP makes the false presumption that due to TSID’s conservation efforts, stream temperatures are falling, but stream temperature data taken over the past decade indicate the opposite.
The optimal temperatures for Steelhead spawning and rearing are 12°C and 18°C, respectively. The HCP sets 20°C as the Whychus Creek temperature target, but it failed to acknowledge that TSID’s current minimum flow of 20 cfs has already resulted in temperatures lethal to fish. For example, in the summer of 2018 temperatures in Whychus Creek exceeded 20°C from June 21st to August 21st. Temperatures exceeded 24°C from July 13th and July 31st. In the summer of 2019, temperatures exceeded 20°C from July 7th to September 5thand exceeded 24°C from July 29th to August 6th. The annual decline of streamflow has and will continue to result in lethally-high water temperatures for fish in Whychus Creek.
There is nothing in the HCP that compels TSID to meet any particular flow or temperature goals. The target of 20°C should instead be linked directly to a conservation measure that would increase streamflows now. Flow/temperature models indicate that 41 cfs is needed at Sisters, or 49 cfs at the TSID diversion, to meet the 20°C target.
Chinook salmon
Despite approximately $50 million of public investment in TSID piping infrastructure over the past twenty years, they have not addressed the needs of our fish and wildlife. The flows are too low, and water temperatures are too high. This is not acceptable. They can and should do better.
The Habitat Conservation Plan (HCP) is an enforceable agreement between irrigation districts and federal agencies meant to reduce the harmful effects of irrigation, but the plan currently put forth is woefully inadequate to address the health of the River, the needs of our farmers and the welfare of fish and wildlife.