Coho Preserve

Cascade Creek flows from the slopes of Mount Constitution to Buck Bay and may be the only salmon bearing stream in the San Juan Islands. Recent stream surveys indicate that the stream supports native anadromous species including coho, Chinook, chum and sea-run cutthroat. Although natural barriers limit spawning to the lower 200 yards, the stream’s largely protected watershed and perennial flow make it unique in the islands.

Over the years, multiple agencies have studied Cascade Creek. Among them are the Washington Department of Ecology, the Washington Department of Fish and Wildlife and Washington State Parks. The San Juan County Conservation Land Bank (Lank Bank) established the 24-acre Coho Preserve in 2016 and retained local biologist Jenny DeGroot of Speckled Trout Consulting to help track fish populations and flow levels in the creek. While there is uncertainty about pre-disturbance fish populations and the genetic origins of surveyed fish, the stream is recognized as a vital resource for native fish and other aquatic species.

Although most of Cascade Creek is protected within Moran State Park, water withdrawals for hydroelectric power generation at Rosario Resort and domestic use in the villages of Olga and Doe Bay and have been shown to reduce instream flow to below critical levels at certain times of the year. Orcas Water Holdings LLC (the former owners of Rosario Resort) owns the largest and most senior water right on Cascade Creek. In 2009, Washington Water Trust purchased a portion of the water right (.25 cfs in June, July and August and .5 cfs in September and October) to help ensure adequate flow for native fish. While this important agreement helped preserve flow for fish, subsequent flow monitoring has revealed periodic inadvertent de-watering of the creek.

As one of many stakeholders in the Cascade Creek watershed the Land Bank seeks to work collaboratively with all willing partners to support native fish and watershed health. In 2020, with a letter of support from Orcas Water Holdings in hand, Land Bank staff applied for and received Recreation and Conservation Office Salmon Recovery and Department of Ecology flow restoration grants totaling approximately $500,000. With these grants, the Land Bank hopes to purchase enough flow to maintain at least 1 cubic foot per second (cfs) of instream flow in Cascade Creek throughout the year. Specifically, this project seeks to project up to 0.75 cfs in June, 0.25 cfs in July and August, 0.5 cfs in September and October, and 1.0 cfs in November and December.

After securing the grants, the Land Bank retained the non-profit Washington Water Trust to support negotiations for a future water rights purchase. Although Orcas Water Holdings has released additional stream flow to support salmon on a voluntary basis, the protracted sale of Rosario Resort has delayed the desired water rights purchase. The Land Bank maintains active communications with Orcas Water Holdings and has worked with grantors to extend both grants to allow for additional time for a sale. At present, the $265,000 Department of Ecology grants end 3/31/2026. The Land Bank is currently seeking an extension of the $250,000 RCO Salmon Recovery grant from 6/30/25 to 6/30/26.