The Delta Plan

Delta Stewardship Council (Delta Council) | May 16th, 2013

The Delta Plan is a comprehensive, long-term management plan for the Delta. Required by the 2009 Delta Reform Act, it creates new rules and recommendations to further the

The Delta Plan is a comprehensive, long-term management plan for the Delta. Required by the 2009 Delta Reform Act, it creates new rules and recommendations to further the state’s coequal goals for the Delta: Improve statewide water supply reliability, and protect and restore a vibrant and healthy Delta ecosystem, all in a manner that preserves, protects and enhances the unique agricultural, cultural, and recreational characteristics of the Delta. Now the Council is considering updates to the Delta Plan. For information about the amendment process, please click here. Developed through eights drafts, hundreds of hours of public meetings and thousands of public comments over two years, the Delta Plan is guided by the best available science and is founded on cooperation and coordination among federal, State and local agencies. The Delta Plan is enforceable through regulatory authority in the Delta Reform Act that requires state and local agencies to be consistent with the Delta Plan. The Delta Plan was unanimously adopted by the Delta Stewardship Council on May 16, 2013. Subsequently its 14 regulatory policies were approved by the Office of Administrative Law, a state agency that ensures the regulations are clear, necessary, legally valid, and available to the public. The Delta Plan became effective with legally-enforceable regulations on September 1, 2013.

The demographic decline of a sea lion population followed multi‐decadal sea surface warming

Nature Portfolio (Springer Nature) | June 26th, 2020

The population growth of top predators depends largely on environmental conditions suitable for aggregating sufficient and high‐quality prey. We reconstructe

The population growth of top predators depends largely on environmental conditions suitable for aggregating sufficient and high‐quality prey. We reconstructed numerically the size of a resident population of California sea lions in the Gulf of California during 1978–2019 and its relation with multi‐decadal sea surface temperature anomalies. This is the first multi‐decadal examination of the sea surface temperature of the Gulf of California and of one of its major predators. A three‐decade sustained warming explained the population’s trend accounting for 92% of the variance, including a 65% decline between 1991 and 2019. Long‐term warming conditions started in the late 80s, followed by the population’s decline from 43,834 animals (range 34,080–58,274) in 1991 to only 15,291 (range 11,861–20,316) in 2019. The models suggested a century‐scale optimum sea surface habitat occurring in mildly temperate waters, from 0.18 to 0.39 °C above the 100‐year mean. The mechanistic links of this relation are still untested, but apparent diversification of pelagic fish catches suggests a reduction of high quality prey. We propose this population should be considered vulnerable to any disturbance that could add to the negative effects of the current warm sea surface conditions in the Gulf of California.

The Economic Value of Nature's Services and its role in Integrated Water Management: Four California Case Studies

California Department of Water Resources (DWR) | July 1st, 2014

Here we present four case studies of integrated regional water management that include enhancement of biological diversity among their goals. Each pilot-scale project foc

Here we present four case studies of integrated regional water management that include enhancement of biological diversity among their goals. Each pilot-scale project focuses on multiple water-related natural resources in a defined geographic area, usually a watershed. A common element of the projects is to show the economic benefits of protecting and restoring natural resources in a manner that allows their continued use over the long term. One of the aims of the projects is to recognize the economic value of the goods and services that nature provides and to incorporate that value into natural resource management decisions. Such recognition includes development of ways to measure the economic value of those services. This can be important information for water managers who normally see only the costs of ecosystem protection and restoration, but not the benefits, in their budgets. The goods and services considered in these projects include water supply, water quality, erosion prevention, wildfire prevention, hydropower generation, wood products, flood attenuation, carbon sequestration, land subsidence reversal, and fish and wildlife. Collectively, the projects constitute on-the-ground efforts to advance several of the objectives in the implementation plan of Water Plan 2009. In particular, they aim to expand integrated regional water management (objective 1), protect surface water and groundwater quality (objective 4), expand environmental stewardship (objective 5), practice integrated flood management (objective 6) and manage a sustainable California Delta (objective 7). The case studies accomplish and document several key ingredients of integrated resource management--although no single study does all of them. They identify and involve watershed stakeholders, both managers and users of natural resources. In turn, the stakeholders come to agreement about how they want the watershed to look or function, usually in terms of the goods and services that they want the watershed to provide. Then they reach agreement on a set of management practices that can support and enhance those services and move the watershed toward the desired condition. Finally, the case studies seek to estimate the amounts of goods and services derived from specific management practices. The pilot projects go beyond most watershed management efforts and most ecosystem services work in laying the foundation for establishment of markets for nature’s services, that is, mechanisms for beneficiaries to pay producers for goods and services they receive. This requires some sort of assessment of the monetary value of the benefits. One desired end product is to put payments in the hands of producers-- that is, resource managers—as an incentive to keep them producing.

The effects of aquatic area abundance, buffer, and hydrology on depressional wetland condition based on CRAM

San Francisco Estuary Institute (SFEI) | April 1st, 2016

The Effects of Salmon Fisheries on Southern Resident Killer Whales

National Marine Fisheries Service (NMFS) | November 30th, 2012

The evolution of dam induced river fragmentation in the United States

Nature Portfolio (Springer Nature) | June 28th, 2023

The Historical Ecology of the Tijuana Estuary & River Valley (Restore America's Estuaries 2018 Conference Presentation)

San Francisco Estuary Institute (SFEI) | December 12th, 2018

This talk was given at the 2018 Restore America's Estuary Conference in Long Beach, CA as part of a special session titled "Restoration Perspectives from the Tijuana Rive

This talk was given at the 2018 Restore America's Estuary Conference in Long Beach, CA as part of a special session titled "Restoration Perspectives from the Tijuana River National Estuarine Research Reserve." It is based on information from the Tijuana River Valley Historical Ecology Investigation, a report published in 2017. Though many areas of the binational Tijuana River watershed remain relatively undeveloped, land and water use changes over the past 200 years have resulted in significant ecological impacts, particularly in the more urbanized areas of the lower watershed. Drawing upon a diverse set of historical data, we reconstructed the ecological and hydrogeomorphic conditions of the lower Tijuana River valley prior to major Euro-American modification (ca. 1850) and documented major changes in habitat distribution and physical processes over this time. The river corridor, which was historically dominated by riparian scrub, today instead supports dense stands of riparian forest. The valley bottom surrounding the river corridor, which historically supported extensive seasonal wetlands, has largely been converted to drier habitat types and agricultural uses. The estuary, which historically supported large expanses of salt marsh and mudflat as well as seasonally dry salt flats, has retained much of its former extent and character, but has been altered by increased sediment input and other factors. The new information about the historical landscape presented here is relevant to a number of issues scientists and managers are dealing with today, including the conservation of endangered species, the fate of the valley’s riparian habitats after the recent invasion of invasive shot-hole borer beetles, and the effects on groundwater levels on native plant communities. We will also draw from other historical ecology studies conducted in Southern California to illustrate how the information about the past has been utilized to improve the functioning and resilience of nearby coastal ecosystems.

The Influence of Zooplankton Availability on Delta Smelt Condition and Foraging Across Habitat Contexts

Publisher not available | December 19th, 2025

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dep

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dependent effects can help optimize and target management efforts. In this analysis, we investigate how environmental and food-web conditions interactively affect condition and foraging of Delta Smelt (Hypomesus transpacificus), an endangered fish endemic to the San Francisco Estuary (the estuary). Food limitation, in terms of pelagic zooplankton availability, is considered a main factor that contributes to the decline in Delta Smelt abundance. Our overarching objective was to examine whether the effect of zooplankton on Delta Smelt depended on habitat context. Specifically, we hypothesized that zooplankton would less positively effect Delta Smelt condition—as measured by hepatosomatic index (HSI)—and foraging success in areas with nearby tidal wetlands, because these adjacent habitats may provide access to prey items from the epibenthos and fringing vegetation. In contrast, in regions with limited proximity to wetlands, we hypothesized that Delta Smelt would rely more on pelagic prey, which would manifest as a more positive effect of zooplankton on body condition and foraging success for Delta Smelt. Using models that accounted for habitat in multiple ways, we found little evidence that zooplankton and habitat interactively influenced Delta Smelt condition or gut fullness. Rather, the influence of zooplankton on HSI and gut fullness was generally positive across habitat contexts. Given the well-documented food limitation in the estuary, promoting the availability of pelagic zooplankton is a rational, albeit complex, management aim. Furthermore, our results suggest that efforts to increase zooplankton would broadly benefit Delta Smelt across a wide range of habitat contexts.

The NOAA NCEI marine microplastics database

Nature Portfolio (Springer Nature) | October 20th, 2023

Microplastics (<5 mm) pollution is a growing problem affecting coastal communities, marine ecosystems, aquatic life, and human health. The widespread occurrence of m

Microplastics (<5 mm) pollution is a growing problem affecting coastal communities, marine ecosystems, aquatic life, and human health. The widespread occurrence of marine microplastics, and the need to curb its threats, require expansive, and continuous monitoring. While microplastic research has increased in recent years and generated significant volumes of data, there is a lack of a robust, open access, and long-term aggregation of this data. The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) now provides a global open access to marine microplastics data on an easily discoverable and accessible GIS web map and data portal. The objective of this data portal is to develop a repository where microplastics data are aggregated, archived, and served in a user friendly, consistent, and reliable manner. This work contributes to NCEI’s efforts towards data standardization, integration, harmonization, and interoperability among national and international collaborators for monitoring global marine microplastics. This paper describes the NOAA NCEI global marine microplastics database, its creation, quality control procedures, and future directions.

The potential of collaborative solutions to improve management of California (United States) wildlands

Restoration Ecology, Society for Ecological Restoration (SER) | November 13th, 2024