Managing hydropower dam releases for water users and imperiled fishes with contrasting thermal habitat requirements

Zarri, Liam J.; Danner, Eric M.; Daniels, Miles E.; Palkovacs, Eric P.

doi:10.1111/1365-2664.13478

Cited by 29 publications

(18 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other CCV native fish species may require different flow conditions during the spring, potentially creating water management conflicts. For example, high flows and cold water from dam releases may have detrimental impacts on threatened green sturgeon ( Acipenser medirostris ) in the Sacramento River (Zarri et al 2019). Similarly, endangered winter‐run Chinook salmon rely on cold water released from Shasta Reservoir during egg development in the summer, which is contingent on water operations that allow sufficient cold water availability in Shasta Reservoir for the summer months (Martin et al 2017).…”

Section: Discussionmentioning

confidence: 99%

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

et al. 2021

Self Cite

View full text Add to dashboard Cite

Water is a fundamental resource in freshwater ecosystems, and streamflow plays a pivotal role in driving riverine ecology and biodiversity. Ecologically functional flows, managed hydrographs that are meant to reproduce the primary components of the natural hydrograph, are touted as a potential way forward to restore ecological functions of highly modified rivers, while also balancing human water needs. A major challenge in implementing functional flows will be establishing the shape of the managed hydrograph so as to optimize improvements to the ecosystem given the limited resources. Identifying the shape of the flow-biology relationship is thus critical for determining the environmental consequences of flow regulation. In California's Central Valley, studies have found that increased streamflow can improve survival of imperiled juvenile salmon populations during their oceanward migration. These studies have not explored the potential nonlinearities between flow and survival, giving resource managers the difficult task of designing flows intended to help salmon without clear guidance on flow targets. We used an information theoretic approach to analyze migration survival data from 2436 acoustic-tagged juvenile Chinook salmon from studies spanning differing water years (2013)(2014)(2015)(2016)(2017)(2018)(2019) to extract actionable information on the flow-survival relationship. This relationship was best described by a step function, with three flow thresholds that we defined as minimum (4259 cfs), historic mean (10,712 cfs), and high (22,872 cfs). Survival varied by flow threshold: 3.0% below minimum, 18.9% between minimum and historic mean, 50.8% between historic mean and high, and 35.3% above high. We used these thresholds to design alternative hydrographs over the same years that included an important component of functional flows: spring pulse flows. We compared predicted cohort migration survival between actual and alternative hydrographs. Managed hydrographs with pulse flows that targeted high survival thresholds were predicted to increase annual cohort migration survival by 55-132% without any additions to the water budget and by 79-330% with a modest addition to the water budget. These quantitative estimates of the biological consequences of different flow thresholds provide resource managers with critical information for designing functional flow regimes that benefit salmon in California's highly constrained water management arena.

show abstract

Section: Discussionmentioning

confidence: 99%

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…To mitigate winter-run Chinook egg and alevin mortality during drought years, two possible strategies for cool-water management are: (1) release cool water early (April-May) to drive the peak of winter-run spawning earlier in an attempt to achieve emergence from gravel before temperatures increase; or (2) hold cool water until later in the season, when the bulk of spawners begin to deposit eggs. There are trade-offs involving the timing of cold water releases for winter-run Chinook and other species (e.g., Green Sturgeon; Zarri et al 2019), and, ultimately, models that combine reservoir management dynamics with SRWC spawning and egg incubation will be necessary to understand how reservoir management might affect spawn timing, egg and alevin development, and egg-tofry survival under various climate conditions.…”

Section: Discussionmentioning

confidence: 99%

Spawn Timing of Winter-Run Chinook Salmon in the Upper Sacramento River

Jennings¹,

Hendrix²

2020

SFEWS

View full text Add to dashboard Cite

Spawn timing in anadromous Pacific salmon may be especially sensitive to environmental cues such as river temperature and flow regimes. In this study, we explored correlations between peak spawn timing and water temperature in endangered Sacramento River winter-run Chinook. In recent drought years, rising water temperatures during egg incubation have negatively impacted winter-run Chinook populations. This paper seeks to understand how winter-run spawn timing may be affected by temperatures during adult spawner staging, and how water releases from Shasta Dam might affect these dynamics. We fit a proportional odds logistic regression model to evaluate annual spawn timing as a function of average temperatures in April and May below Keswick Dam. While the start date of spawning remains relatively constant from year-to-year, there is annual variability in when the majority of spawning occurs. Cool springtime temperatures trigger winter-run Chinook to spawn earlier, whereas warm springtime temperatures trigger fish to spawn later. Prior to dam construction, winter-run Chinook spawned in cool, spring-fed streams that are now inaccessible to migrating salmonids. Temperature-driven spawn timing would have primarily ensured sufficient time for egg maturation in cool years, while secondarily preventing mortality in warm years. In the current winter-run Chinook spawning grounds, this relationship may have important applications to management of Shasta Dam water releases during conditions when thermal mortality can affect developing winter-run Chinook eggs.

show abstract

“…However, owing to the diversity of diadromous fishes in a watershed, a water release plan that is optimized for one species can have negative consequences for another species (Zarri et al. 2019).…”

Section: Current State Of Knowledgementioning

confidence: 99%

A Review of River Herring Science in Support of Species Conservation and Ecosystem Restoration

et al. 2021

View full text Add to dashboard Cite

River herring—a collective name for the Alewife Alosa pseudoharengus and Blueback Herring A. aestivalis—play a crucial role in freshwater and marine ecosystems along the Eastern Seaboard of North America. River herring are anadromous and return to freshwater habitats in the tens to hundreds of millions to spawn, supplying food to many species and providing nutrients to freshwater ecosystems. After two and a half centuries of habitat loss, habitat degradation, and overfishing, river herring are at historic lows. In 2013, National Oceanic and Atmospheric Administration Fisheries established the Technical Expert Working Group (TEWG) to synthesize information about river herring and to provide recommendations to advance the science related to their restoration. This paper was composed largely by the chairs of the TEWG subgroups and represents a review of the current state of knowledge of river herring, with an emphasis on identification of threats and discussion of recent research and management actions related to understanding and reducing these threats. Important research needs are then identified and discussed. Finally, current knowledge is synthesized, considering the relative importance of different threats. This synthesis identifies dam removal and increased stream connectivity as critical to river herring restoration. Better understanding and accounting for predation, climate change, and fisheries are also important for restoration. Finally, there is recent evidence that the effects of human development and contamination on habitat quality may be more important threats than previously recognized. Given the range of threats, an ecosystem approach is needed to be successful with river herring restoration. To facilitate this ecosystem approach, collaborative forums such as the TEWG (renamed the Atlantic Coast River Herring Collaborative Forum in 2020) are needed to share and synthesize information among river herring managers, researchers, and community groups from across the species’ range.

show abstract

Managing hydropower dam releases for water users and imperiled fishes with contrasting thermal habitat requirements

Cited by 29 publications

References 37 publications

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

Spawn Timing of Winter-Run Chinook Salmon in the Upper Sacramento River

A Review of River Herring Science in Support of Species Conservation and Ecosystem Restoration

Contact Info

Product

Resources

About