San Joaquin River

Modeling the effect of habitat availability and quality on endangered winter-run Chinook salmon (Oncorhynchus tshawytscha) production in the Sacramento Valley

Ecological Modelling (Elsevier) | March 13th, 2021

Reconciliation between water uses and sustaining aquatic species populations requires an effort to identify and quantify essential habitat characteristics for ecosystem h

Reconciliation between water uses and sustaining aquatic species populations requires an effort to identify and quantify essential habitat characteristics for ecosystem health and valuation methods to predict ecosystem response to restoration actions. This process is particularly challenging for anadromous fish species such as California's Sacramento River winter-run Chinook salmon, due to their limited geographic range and diverse life history habitat requirements. Tools, such as life-cycle models, are needed to manage population dynamics and quantify the composite effects of processes across space and time. Nevertheless, complex institutions can hinder result interpretation and communication, and limit model use in decision-making. This paper focuses on the federally endangered and endemic Sacramento River winter-run Chinook (Oncorhynchus tshawytscha) by developing a Winter-Run Habitat-based Population Model (WRHAP). WRHAP is a conceptual, freshwater rearing stage model that includes alternative rearing habitats reported in the literature (e.g., floodplains, off-channel and tributaries), defines rules of habitat use based on instream conditions, and incorporates a juvenile growth module that combines bioenergetics modeling with empirical growth rates. Model outputs reasonably follow observed out-migration patterns and provide a realistic smolt size distribution arriving at the San Francisco Bay. This effort demonstrates the importance of currently “non-critical” habitats (as defined by the Endangered Species Act) for juvenile development, with floodplain habitat contributing to a quarter of out-migrating biomass (despite < 18% availability and <10% of total rearing days), and off-channel growth being one of the most sensitive parameters (explaining ~13% of average juvenile weight variance). The model shows the utility of a simple population model to explore relationships between habitat quality/quantity and juvenile development, and to assist water/environmental management and decision-making processes focused on species recovery.

Modernizing the system: California Water Fix finance and cost allocation (White paper #3)

Metropolitan Water District of Southern California (MWD) | August 10th, 2017

The third in a series of policy papers prepared for the consideration of Metropolitan’s Board of Directors in advance of planned summer meetings and decisions in fall 2

The third in a series of policy papers prepared for the consideration of Metropolitan’s Board of Directors in advance of planned summer meetings and decisions in fall 2017. Modernizing and improving California’s water system is essential for the reliable delivery of water supplies to much of the state. About 30 percent of the water that flows out of taps in Southern California homes and businesses comes from Northern California watersheds and flows through the Sacramento-San Joaquin Delta. But the Delta’s declining ecosystem and 1,100 miles of levees are increasingly vulnerable to earthquakes, flooding, saltwater intrusion, climate change and further environmental degradation. California WaterFix is the product of more than a decade of review, planning, rigorous scientific and environmental analysis and unprecedented public comment. This white paper provides information about the costs of the project, including adjustments of capital, mitigation and O&M costs to 2017 dollars. The financing plan is presented with financial assumptions and a range of financing scenarios. The cost allocation information covers Metropolitan’s anticipated financial commitment, an estimate of member agency wholesale rate impacts, and metrics to assess retail level impacts. Using this information and when compared to costs for other local supply alternatives, California WaterFix would provide a cost-effective supply for Southern California’s water portfolio.

Modernizing the system: California Water Fix Infrastructure (White paper #1)

Metropolitan Water District of Southern California (MWD) | July 3rd, 2017

The first in a series of three policy papers prepared for the consideration of Metropolitan Water District’s Board of Directors in advance of planned summer meetings an

The first in a series of three policy papers prepared for the consideration of Metropolitan Water District’s Board of Directors in advance of planned summer meetings and decisions in Fall 2017. Modernizing and improving California’s water system is essential for the reliable delivery of water supplies to much of the state. About 30 percent of the water that flows out of taps in Southern California homes and businesses comes from Northern California watersheds and flows through the Sacramento-San Joaquin Delta. But the Delta’s declining ecosystem and 1,100 miles of levees are increasingly vulnerable to earthquakes, flooding, saltwater intrusion, climate change and further environmental degradation. California WaterFix is the product of more than a decade of review, planning, and rigorous scientific and environmental analysis by water experts, engineers and conservationists, as well as unprecedented public comment. The proposed project will improve the security of our water system by fixing aging infrastructure and constructing new, state-of-the art facilities using innovative technologies and engineering practices. Significant planning work for the design and construction of the project has been performed by the state, water agencies, and construction and engineering firms, which have determined the project is buildable. Details of the project features, actions to address public comment, risk management, schedule projection and cost estimates are addressed in a new white paper and summarized below.

Modernizing the system: California Water Fix operations (White paper #2)

Metropolitan Water District of Southern California (MWD) | July 20th, 2017

The second in a series of three policy papers prepared for the consideration of Metropolitan’s Board of Directors in advance of planned summer meetings and decisions in

The second in a series of three policy papers prepared for the consideration of Metropolitan’s Board of Directors in advance of planned summer meetings and decisions in fall 2017. Modernizing and improving California’s water system are essential for the reliable delivery of water supplies to much of the state. About 30 percent of the water that flows out of taps in Southern California homes and businesses comes from Northern California watersheds and flows through the Sacramento-San Joaquin Delta. But the Delta’s declining ecosystem and 1,100 miles of levees are increasingly vulnerable to earthquakes, flooding, saltwater intrusion, climate change and further environmental degradation. California WaterFix is the product of more than a decade of review, planning, rigorous scientific and environmental analysis in collaboration with fishery agencies and an unprecedented level of public comment. Extensive analysis and work has been performed by state and federal water agencies and fish and wildlife agencies to determine conveyance system improvements and an operations framework to improve the direction of river flows in ways that will help native fish species, protect water supplies from climate change impacts and help restore the Delta ecosystem. Details of the proposed operations are addressed in Metropolitan’s second white paper and summarized below.

Modesto Subbasin Groundwater Sustainability Plan

Stanislaus and Tuolumne Rivers Groundwater Basin Association (STRGBA) | January 31st, 2022

This Groundwater Sustainability Plan (GSP) covers the entire Modesto Subbasin (5-22.02), designated a high-priority basin by the Department of Water Resources (DWR). The

This Groundwater Sustainability Plan (GSP) covers the entire Modesto Subbasin (5-22.02), designated a high-priority basin by the Department of Water Resources (DWR). The Modesto Subbasin covers about 245,253 acres in the northern San Joaquin Valley Groundwater Basin and is bounded by the Stanislaus River on the north, the Tuolumne River on the south, the San Joaquin River on the west and the crystalline basement rocks of the Sierra Nevada Foothills on the east. The Modesto Subbasin relies on two primary sources of water supply – surface water from the Stanislaus and Tuolumne rivers and groundwater pumped from the Subbasin. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4

Modesto Subbasin Groundwater Sustainability Plan

Stanislaus and Tuolumne Rivers Groundwater Basin Association (STRGBA) | January 31st, 2022

This Groundwater Sustainability Plan (GSP) covers the entire Modesto Subbasin (5-22.02), designated a high-priority basin by the Department of Water Resources (DWR). The

This Groundwater Sustainability Plan (GSP) covers the entire Modesto Subbasin (5-22.02), designated a high-priority basin by the Department of Water Resources (DWR). The Modesto Subbasin covers about 245,253 acres in the northern San Joaquin Valley Groundwater Basin and is bounded by the Stanislaus River on the north, the Tuolumne River on the south, the San Joaquin River on the west and the crystalline basement rocks of the Sierra Nevada Foothills on the east. The Modesto Subbasin relies on two primary sources of water supply – surface water from the Stanislaus and Tuolumne rivers and groundwater pumped from the Subbasin. Due to size, this file has been divided into four parts. Part 1, Part 2, Part 3, Part 4

Modesto Subbasin Groundwater Sustainability Plan (Revised)

Publisher not available | July 12th, 2024

Submitted to the Department of Water Resources (DWR) in January 2022, the first version of this GSP was reviewed by DWR in January 2024 and determined to be incomplete (D

Submitted to the Department of Water Resources (DWR) in January 2022, the first version of this GSP was reviewed by DWR in January 2024 and determined to be incomplete (DWR, 2024). Two deficiencies were identified by DWR. The first of these involves provision of sufficient information (namely, analysis of potential impacts on wells) to support the selection of sustainable management criteria for chronic lowering of groundwater levels. The second involves provision of sufficient details on the projects and management actions to mitigate overdraft in the Subbasin and provide a feasible path to achieve sustainability. Corrective actions, including a resolution approved by both GSAs to arrest groundwater level declines by 2027 and raise groundwater levels after 2027, are incorporated into this revised July 16, 2024, GSP for resubmittal to DWR. This GSP is a revised version and does not represent a GSP update, which is slated for 2027. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4

Mokelumne watershed avoided cost analysis: Why Sierra fuel treatments make economic sense

Sierra Nevada Conservancy | April 10th, 2014

High-severity wildfires in forests of California’s Sierra Nevada pose a serious threat to people and nature. Although proactive forest management can reduce the risk of

High-severity wildfires in forests of California’s Sierra Nevada pose a serious threat to people and nature. Although proactive forest management can reduce the risk of high-severity wildfire, the pace and scale of fuel treatments is insufficient, given the growing scope of the problem. Using the upper Mokelumne River watershed as a representative case, we sought to answer the following question: Does it make economic sense to increase investment in fuel treatments to reduce the risk of large, damaging wildfires? Our analysis suggests that the economic benefits of landscape- scale fuel-reduction treatments far outweigh the costs of wildfire. 

Monitoring Special Study (MSS) Salinity Point Source and Ion Sampling CY 2022–2023

California Department of Water Resources (DWR) | August 15th, 2022

The interior southern Delta region of the San Francisco Estuary (SFE) has relatively higher seasonal-based salinity compared to other interior freshwater regions. Some of

The interior southern Delta region of the San Francisco Estuary (SFE) has relatively higher seasonal-based salinity compared to other interior freshwater regions. Some of this degradation in water quality in the interior southern Delta likely originates in upstream salt loading from agriculture drainage in the San Joaquin River prior to reaching the channels of Old River and Grant Line Canal. However, there is also measurable increases in salt loading within the channel networks of Old River at Head (OH1) east to lower Old River near Mountain House Creek (ORM) and the interconnected sloughs of Paradise and Sugar Cut in the region of Doughty Cut (Figure 1) (in-Delta agriculture drainage), as well as other naturally occurring (i.e., groundwater) sources and other non-point and point sources. The California Department of Water Resources (DWR) and U.S. Bureau of Reclamation (Reclamation), under the State Water Resources Control Board’s (State Water Board) Water Right Decision 1641 (D-1641), are assigned partial responsibility for meeting interior southern Delta water quality objectives each year at multiple compliance stations that measure specific conductance (EC) data continuously at 15-minute intervals.

More state and local attention to financing can advance sustainable groundwater management

Berkeley Law Center for Law, Energy, & the Environment | April 12th, 2025