{"id":4058,"date":"2022-01-31T21:08:52","date_gmt":"2022-02-01T05:08:52","guid":{"rendered":"https:\/\/calsport.org\/fisheriesblog\/?p=4058"},"modified":"2022-01-31T21:08:52","modified_gmt":"2022-02-01T05:08:52","slug":"yuba-river-salmon-in-2022","status":"publish","type":"post","link":"https:\/\/calsport.org\/fisheriesblog\/?p=4058","title":{"rendered":"Yuba River Salmon in 2022"},"content":{"rendered":"

In a December 2020 post<\/a>, I described the status of the fall-run salmon population in the Yuba River.\u00a0 Hatchery salmon predominate, while natural production is minimal.\u00a0 The population remains in a very poor state \u2013 at about 10% of recent historical levels during and subsequent to multiyear droughts such as 2007-2009 and 2013-2015 (Figure 1).<\/p>\n

In a January 11, 2022 post<\/a>, the South Yuba River Citizens League (SYRCL) promotes cleaning the two fish ladders at Daguerre Dam half way up the river to the impassable Englebright Dam, in order to provide better passage for spawning salmon to prime spawning habitat.\u00a0 Without effective ladders, salmon are delayed or even forced to spawn downstream of Daguerre Dam in marginal habitat.\u00a0 The ladders must be maintained per the federal NMFS biological opinion and take permit to operate Daguerre Dam as a water diversion dam for the Yuba County Water Agency (YCWA).<\/p>\n

SYRCL\u2019s plea to clean the fish ladders is helpful in bringing attention to the problems facing salmon (and steelhead) in the lower Yuba River.\u00a0 However, the fish ladders at Daguerre are only a small part of the problem for Yuba River salmon.\u00a0 River flows and habitat in the lower Yuba River need improvement.<\/p>\n

River Flows<\/strong><\/p>\n

It is instructive to compare flows in 2020 (Figure 2) to flows in 2021 (Figure 3), particularly at the Marysville gage, where water has passed downstream of all the local agricultural diversions at Daguerre Dam.<\/p>\n

2020<\/strong><\/p>\n

From May through mid-August of 2020, flows at Marysville averaged about 1000 cfs (Figure 2). \u00a0The vast majority of this water was released through YCWA\u2019s New Colgate Powerhouse upstream of Englebright Dam.\u00a0 In the fiscal year from July 1, 2020 to June 30, 2021, YCWA had revenues from power sales of over $80 million. 1<\/a><\/sup> Water released during the summer creates more power revenue than flows released in spring.<\/p>\n

Better management for fish would release more of the water in the spring, providing more areas in the lower Yuba River for juvenile salmon and steelhead to grow and higher flows to move them downstream when they are ready to leave the system.\u00a0 SYRCL, CSPA, and other conservation organizations, as well as staff from fisheries agencies, have recommended such a change in release pattern during the ongoing relicensing of YCWA\u2019s hydropower project.<\/p>\n

Some of this water released in the summer of 2020 was also sold out of the watershed, generally to entities south of the Delta.\u00a0 In the fiscal year ending June 30, 2021, YCWA also made $12 million on water sales.2<\/a><\/sup> The large flow increase at the end of August 2020 \u2013 likely a water sale \u2013 had no benefit for fish.\u00a0 Its biggest effect on fish was that It drew down storage in New Bullards Bar Reservoir, which created a cascading effect in the very dry year 2021, when flows for all purposes were limited by lack of stored water.<\/p>\n

2021<\/strong><\/p>\n

In a very dry year like 2021 that follows a dry year like 2020, river flows in spring and summer (Figure 3) become a major limiting factor.\u00a0 First, there are no late-winter, early-spring flow pulses to attract adult spring-run salmon.\u00a0 At a flow of 400 cfs at the bottom end of the lower Yuba River, there is insufficient flow to help adult spring-run salmon move upstream through many shallow riffles and through the Daguerre ladders. \u00a0Very low late-summer and fall low flows likewise hinder fall-run salmon.\u00a0 Second, flows in late winter and early spring are too low to efficiently carry juvenile salmon downstream while avoiding the many predators on their way to the Bay and ocean.\u00a0 Downstream of Daguerre Dam, over-summering juvenile salmon and steelhead must contend with low flows and associated stressful water temperatures.\u00a0 Additionally, spawning at 400 cfs flow leads to redd scour if fall rainstorms occur: a late-October storm in 2021 brought Yuba flows up to 15,000 cfs and raised water levels nearly 10 feet (Figure 4).<\/p>\n

Habitat<\/strong><\/p>\n

Feeding and cover habitat in the lower Yuba River are virtually nonexistent.\u00a0 Predatory fish abound below Daguerre Dam.\u00a0 Floodplain off-channel habitat and woody debris are severely lacking, especially during when winter-spring river flows are relatively low.\u00a0 Many fall-run salmon spawn in poor spawning habitat below Daguerre. \u00a0To its credit, YCWA has contributed on a voluntary basis to several habitat improvement projects in the lower Yuba River, including the ongoing restoration at Hallwood.\u00a0 However, it has vigorously resisted the establishment of regulatory requirements for additional projects.<\/p>\n

Biological Opinion (BO<\/a>)<\/strong><\/p>\n

Keeping the ladders clean is already a mandate.<\/p>\n