The Klamath River is closed to salmon fishing again this fall after the number of fish caught reached the small allotted quotas1. Poor run size (escapement) continues to be a problem, especially for the Scott River, a major spawning tributary of the Klamath. The 2015-2017 Scott run was approximately 2000 spawners, as compared to over 12,000 in 2014. Few fall-run salmon have been counted in the Scott this fall, compared to 4500 on the Shasta River. A past post describes the problem in detail.
The key factor in the decline of Scott fall Chinook has been poor late summer and early fall flows. Low flows do not allow adult salmon to ascend the Scott from the Klamath. This not only hurts that year’s Scott run, but out-year Scott (and Klamath) returns two to five years later.
The problem is especially acute this fall, with flows less than 10 cfs, less than 20% of the historical average (Figure 1). In fall 2017, flows were near or above average (Figure 2), leading to a small increase in the run to 2500, despite poor flows during the 2013-2015 drought. The strong 2014 run also helped.
The solution is simple: stop irrigating pastures and hayfields in Scott Valley after September 1. Many ranchers do, especially for hayfields, but not all. If that is not possible, there are many idle wells of 5-10 cfs capacity each that could pump water into the river to keep the river adequately watered, with little threat to subsequent winter groundwater recharge. A battle is brewing over Scott River water use and the public trust salmon resources.