Relationship of Delta Cross Channel Gate Operations to Loss of Juvenile Winter-run Chinook Salmon at the CVP/SWP Delta Facilities

California Department of Fish and Wildlife (CDFW) | July 1st, 2003

Winter-run Chinook salmon are distinguishable from the three other Chinook runs in the Sacramento River system by the timing of their upstream migration and spawning. Due

Winter-run Chinook salmon are distinguishable from the three other Chinook runs in the Sacramento River system by the timing of their upstream migration and spawning. Due to precipitous decline in the population from the late 1960’s through the late 1980’s, NOAA Fisheries listed the run as “threatened” in August 1989, and subsequently reclassified the run as “endangered” in 1992. The state of California listed the run as endangered in 1989.  Many factors contributed to the decline in the winter-run Chinook population. Among these factors, operation of the federal Central Valley Project and State Water Project has had continuing impacts on winter-run Chinook. Of particular concern have been the direct entrainment losses of juvenile winter-run Chinook at the project export facilities in the Delta. 

Report on the Delta Drought Response Pilot Program for Water Year 2023

Sacramento-San Joaquin Delta Conservancy | July 24th, 2024

This report describes the 2023 Delta Drought Response Pilot Program (DDRPP/Program), provides an analysis of the Program’s effectiveness, and describes the Program outc

This report describes the 2023 Delta Drought Response Pilot Program (DDRPP/Program), provides an analysis of the Program’s effectiveness, and describes the Program outcomes, including findings and recommendations for application in future agricultural water conservation programs. The DDRPP launched in January 2022 as a response to the continuing risk of drought in the Sacramento-San Joaquin Delta Watershed. This report focuses on the results of the 2023 Program, with a brief analysis comparing both years of the Program. For detailed information on the 2022 Program and 2022 analysis, see the 2022 DDRPP Final Report (Sacramento-San Joaquin Delta Conservancy, 2023).

Residential irrigation as a driver of urban bird communities

Nature Portfolio (Springer Nature) | August 17th, 2009

The demand for fresh water has largely outpaced supply both globally and locally with current water management policies unable to meet the needs of urban, agricultural, a

The demand for fresh water has largely outpaced supply both globally and locally with current water management policies unable to meet the needs of urban, agricultural, and industrial activities. Irrigation is one of the many anthropogenic uses of water and is arguably the most important maintenance factor in a landscape. This is particularly true in an arid climate, such as the Central Valley of California. Urban residents' decisions about the design and maintenance of their landscapes affect bird species richness. Published research indicates that these decisions are also affected by the residents' socioeconomic status. However, the driver of this relationship remains unknown. This paper uses data from the Fresno Bird Count, a citizen science organization, to test the hypothesis that neighborhood socioeconomic status influences residential irrigation regimes, which influences plant cover, in turn influencing bird diversity and abundance. A random sampling grid containing 460 points are used as locations for five minute point counts for the Fresno Bird Count ("fresnobirds.org":http://fresnobirds.org/). Socioeconomic data has been obtained from the U.S. Census and irrigation regimes from the city of Fresno. Aerial imagery and ground sampling on point count locations are used for characterizing habitat. Preliminary analysis of the first year of data (2008) supports this hypothesis and reveals a north/south gradient of bird diversity paralleling the socioeconomic gradient of Fresno. This paper will present results from a more comprehensive analysis of data including the spring 2009 bird census. Policies in the U.S. regarding the distribution and cost of water are changing in response to increased water demands, and the city of Fresno is about to undergo such a change. In 2013 a policy of metered water is scheduled to begin, which is predicted to increase water conservation by residents due to an increase in it overall cost. In addition to examining coupled socio-ecological drivers of urban diversity, this study will be the first part of a Before After Control Impact experiment taking advantage of the planned implementation of metering the cost of water use. The results can help guide the city in improving its management of urban habitat and biodiversity.

Resilient by Design Bay Area Challenge Briefing Book

San Francisco Estuary Institute (SFEI) | July 1st, 2017

The Resilient by Design Bay Area Challenge Briefing Book is intended as a reference guide for Design Teams as they embark on the Challenge. The aim is to provide com

The Resilient by Design Bay Area Challenge Briefing Book is intended as a reference guide for Design Teams as they embark on the Challenge. The aim is to provide compilation of useful existing resources and context pertaining to resilience in the Bay Area.

Resilient landscape vision for Lower Walnut Creek

San Francisco Estuary Institute (SFEI) | November 30th, 2016

Lower Walnut Creek (Contra Costa County, CA) and its surrounding landscape have undergone considerable land reclamation and development since the mid-nineteenth century.

Lower Walnut Creek (Contra Costa County, CA) and its surrounding landscape have undergone considerable land reclamation and development since the mid-nineteenth century. In 1965, the lower 22 miles of Walnut Creek and the lower reaches of major tributaries were converted to flood control channels to protect the surrounding developed land. In the recent past, sediment was periodically removed from the lower Walnut Creek Flood Control Channel to provide flow capacity and necessary flood protection. Due to the wildlife impacts and costs associated with this practice, the Contra Costa County Flood Control and Water Conservation District (District) is now seeking a new channel management approach that works with natural processes and benefits people and wildlife in a cost-effective manner. Flood Control 2.0 project scientists and a Regional Science Advisory Team (RSAT) worked with the District to develop a long-term management Vision for lower Walnut Creek that could result in a multi-benefit landscape that restores lost habitat and is resilient under a changing climate. Development of the Vision began with technical analyses focused on understanding past and present landscape functioning and the changes to key processes and landscape features over the past 150 to 200 years. The key findings from these analyses include the following: • Landscape change – During the mid-19th century, lower Walnut Creek was surrounded by a continuous expanse of tidal wetlands occupying approximately 5,000 acres. Perennial freshwater marsh, willow thicket, and alkali meadow formed a large non-tidal wetland complex that adjoined the tidal marsh on its southern end. Over the past century and a half, the non-tidal wetland complex has been lost completely and the tidal wetland area has decreased by 40%. The remaining marsh areas are highly fragmented and cut-off from Walnut Creek by engineered levees. The loss of tidal wetland area has resulted in a substantial decrease in tidal prism and contributed to current in-channel sediment accumulation issues. Around the mouth of Walnut Creek, sediment accumulation has caused the position of the shoreline to expand into the Bay by up to half a mile. • Sediment accumulation – Since 1965, approximately 1.4M cubic yards of sediment have been removed from lower Walnut Creek, with approximately 70% coming from the tidal zone downstream of head of tide (i.e., the inland extent of tidal inundation at mean higher high water). Repeat channel cross-section surveys indicate that the channel quickly fills in with sediment following dredging events (due in large part to decreased tidal prism and associated channel scour capacity) and that the channel bed elevation is currently at or near “quasi-equilibrium.” A channel sediment budget for 1965-2007 indicates that approximately 80% of the watershed-derived sediment made it through lower Walnut Creek and out to the Bay, while the remaining 20% was likely deposited directly following channel construction and subsequent dredging events.

Response in the water quality of the Salton Sea, California, to changes in phosphorus loading: an empirical modeling approach

Hydrobiologia (Springer) | January 10th, 2008

Salton Sea, California, like many other lakes, has become eutrophic because of excessive nutrient loading, primarily phosphorus (P). A Total Maximum Daily Load (TMDL)

Salton Sea, California, like many other lakes, has become eutrophic because of excessive nutrient loading, primarily phosphorus (P). A Total Maximum Daily Load (TMDL) is being prepared for P to reduce the input of P to the Sea. In order to better understand how P-load reductions should affect the average annual water quality of this terminal saline lake, three different eutrophication programs (BATHTUB, WiLMS, and the Seepage Lake Model) were applied. After verifying that specific empirical models within these programs were applicable to this saline lake, each model was calibrated using water quality and nutrient-loading data for 1999 and then used to simulate the effects of specific P-load reductions. Model simulations indicate that a 50% decrease in external P loading would decrease near-surface total phosphorus concentrations (TP) by 25– 50%. Application of other empirical models demonstrated that this decrease in loading should decrease near-surface chlorophyll a concentrations (Chl a) by 17–63% and increase Secchi depths (SD) by 38–97%. The wide range in estimated responses in Chl a and SD were primarily caused by uncertainty in how non-algal turbidity would respond to P-load reductions. If only the models most applicable to the Salton Sea are considered, a 70–90% P-load reduction is required for the Sea to be classified as moderately eutrophic (trophic state index of 55). These models simulate steady-state conditions in the Sea; therefore, it is difficult to ascertain how long it would take for the simulated changes to occur after load reductions.

Response to the Delta Science Program and Independent Review Panel Report from the 2015 Annual Review of the Long-term Operation Biological Opinions (2015 Annual Review) (January 29, 2016)

Delta Stewardship Council (Delta Council) | January 29th, 2016

Restoration pulse flows from a California dam temporarily increase drifting invertebrate biomass concentration

Journal of Environmental Management (Elsevier) | November 9th, 2022

The decline of Pacific salmon (Oncorhynchus spp.) populations over the last few decades has stimulated major restoration efforts across the Pacific Northwest to improve t

The decline of Pacific salmon (Oncorhynchus spp.) populations over the last few decades has stimulated major restoration efforts across the Pacific Northwest to improve the status of these iconic fishes. The leading factors contributing to the decline of Pacific salmon include watershed degradation and water diversions, which result in part from widespread dam construction across the United States (Moyle, 1994). Early river restoration actions primarily focused on physical habitat alterations (e.g., in-stream habitat improvement, fish passage; Barinaga, 1996; Bernhardt et al., 2005), while more recent work has centered around restoring natural processes (Johnson et al., 2019). Since socioeconomic and political complications are typically too great for dam removal projects to be feasible, reconciliation ecology, which encourages the accommodation of both human and wildlife needs in a human-dominated landscape, can be a more effective approach to restoration (Rosenzweig, 2003; Moyle et al., 2017). Rather than the elusive goal of returning rivers to a natural flow regime, the aim can be to attain functional environmental flows to support beneficial flow-ecology relationships (Poff et al., 2017). Dams can be operated to reduce some of their detrimental effects by releasing flows that improve downstream habitat through the preservation of key hydrologic signals upon which biophysical processes and native biological communities depend (Yarnell et al., 2020). Four functional flow components were identified for Mediterranean montane streams: wet-season initiation flows, peak magnitude flows, spring recession flows, and dry-season low flows; see Yarnell et al. (2015) for a description about the importance of each key functional component. Several studies have identified the need to further assess linkages between streamflow, invertebrate prey availability, and drift-foraging dynamics for consideration in future restoration plans for juvenile salmonids (Weber et al., 2014; Naman et al., 2016; Lusardi et al., 2018). The focus of this study is to assess the impact of dam-release flows imitating one of those functional flow components, peak magnitude flows, on invertebrate drift as a food resource for juvenile salmonids.

Restoration Vision for the Laguna de Santa Rosa

San Francisco Estuary Institute (SFEI) | April 1st, 2020

The Laguna de Santa Rosa, located in the Russian River watershed in Sonoma County, CA, is an expansive freshwater wetland complex that hosts a rich diversity of plant a

The Laguna de Santa Rosa, located in the Russian River watershed in Sonoma County, CA, is an expansive freshwater wetland complex that hosts a rich diversity of plant and wildlife species, many of which are federally or state listed as threatened, endangered, or species of special concern. The Laguna is also home to a thriving agricultural community that depends on the land for its livelihood. Since the mid-19th century, development within the Laguna and its surrounding watershed have had a considerable impact on the landscape, affecting both wildlife and people. Compared to predevelopment conditions, the Laguna currently experiences increased stormwater runoff and flooding, increased delivery and accumulation of fine sediment and nutrients, spread of problematic invasive species, and decreased habitat for native fish and wildlife species. Predicted changes in future precipitation patterns and summertime air temperatures, combined with expanding development pressure, could exacerbate these problems. People who manage land and regulate land management decisions in and around the Laguna, including landowners; federal, state, and local agencies; and local stakeholders, are seeking a long-term management approach for the Laguna that improves conditions for the wildlife and people that call the Laguna home. The California Department of Fish and Wildlife and Sonoma Water funded the Laguna-Mark West Creek Watershed Master Restoration Planning Project to develop such a management approach, focusing on the need to identify restoration and management actions that enhance desired ecological functions of the Laguna, while also supporting the area’s agriculture and its local residents.

Restoring Habitat with Science and Society in Mind

Delta Stewardship Council (Delta Council) | April 8th, 2014

This Issue Paper, authored by Jessica Davenport, the Council's Program Manager for Ecosystem Restoration and Land Use, is entitled Restoring Habitat with Science and Soci

This Issue Paper, authored by Jessica Davenport, the Council's Program Manager for Ecosystem Restoration and Land Use, is entitled Restoring Habitat with Science and Society in Mind.  The purpose of the 22-page paper is to survey restoration activities in the Delta; describe the needs, progress and opportunities related to restoration; and propose key areas of focus for the Delta Stewardship Council and other agencies to advance habitat restoration. Some of the areas of focus for Council staff for the next two years include: Continue to provide early consultation on habitat restoration projects that are Covered Actions under the Delta Plan in order to advise project proponents on using best available science and adaptive management and avoiding or reducing conflicts with existing uses, where feasible. Report on habitat performance measures by December 2014 and again in December 2015. Work with others to complete at least one of the landscape-scale conceptual models and associated landscape habitat metrics for the priority habitat restoration areas. Enagage Delta Plan Interagency Implementation Committee members in discussions of challenges and potential solutions related to land acquistion and permit coordination.