Brackish Water Desalination Facility Project

Delta Stewardship Council (Delta Council) | April 1st, 2020

The City of Antioch (City) is proposing the Brackish Water Desalination Project (Project), which consists of the construction of a desalination facility at the City’s

The City of Antioch (City) is proposing the Brackish Water Desalination Project (Project), which consists of the construction of a desalination facility at the City’s water treatment plant (WTP) with the capacity to produce up to 6 million gallons per day (mgd) of finished water; demolition of the existing San Joaquin River intake pump station; construction of a new intake pump station; approximately 3,000 feet of pipeline from the existing raw water pipeline underneath Lone Tree Way to the City’s WTP to allow a direct connection to maximize use of existing infrastructure; and approximately 4 miles of pipeline from the desalination facility to the Delta Diablo wastewater treatment plant (WWTP) to discharge brine with the WWTP effluent through the existing Delta Diablo outfall to New York Slough. The Project facilities would be located in the cities of Antioch and Pittsburg, California (Figure 1), at the western edge of the San Joaquin- Sacramento Delta (Delta). The main objectives of the Project are to improve water supply reliability and water quality for its customers; develop a reliable and drought-resistance water source to reduce dependency on purchased water supplies; maximize and preserve the use of the City’s pre-1914 water rights; and provide cost effective operational flexibility for the City.

Central Valley Project and State Water Project Drought Operations Plan and Operational Forecast April 1, 2014 through November 15, 2014

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

Classifying California’s stream thermal regimes for cold-water conservation

PLOS | August 20th, 2021

Stream temperature science and management is rapidly shifting from single-metric driven approaches to multi-metric, thermal regime characterizations of streamscapes. Giv

Stream temperature science and management is rapidly shifting from single-metric driven approaches to multi-metric, thermal regime characterizations of streamscapes. Given considerable investments in recovery of cold-water fisheries (e.g., Pacific salmon and other declining native species), understanding where cold water is likely to persist, and how coldwater thermal regimes vary, is critical for conservation. California’s unique position at the southern end of cold-water ecosystems in the northern hemisphere, variable geography and hydrology, and extensive flow regulation requires a systematic approach to thermal regime classification. We used publicly available, long-term (> 8 years) stream temperature data from 77 sites across California to model their thermal regimes, calculate three temperature metrics, and use the metrics to classify each regime with an agglomerative nesting algorithm. Then, we assessed the variation in each class and considered underlying physical or anthropogenic factors that could explain differences between classes. Finally, we considered how different classes might fit existing criteria for cool- or cold-water thermal regimes, and how those differences complicate efforts to manage stream temperature through regulation. Our results demonstrate that cool- and cold-water thermal regimes vary spatially across California. Several salient findings emerge from this study. Groundwater-dominated streams are a ubiquitous, but as yet, poorly explored class of thermal regimes. Further, flow regulation below dams imposes serial discontinuities, including artificial thermal regimes on downstream ecosystems. Finally, and contrary to what is often assumed, California reservoirs do not contain sufficient cold-water storage to replicate desirable, reach-scale thermal regimes. While barriers to cold-water conservation are considerable and the trajectory of cold-water species towards extinction is dire, protecting reaches that demonstrate resilience to climate warming remains worthwhile.

Climate Change and Integrated Regional Water Management in California: A Preliminary Assessment of Regional Approaches

California Department of Water Resources (DWR) | June 6th, 2012

This report examines the initial steps that IRWM regions are taking in response to new requirements to address climate change vulnerabilities and consider greenhouse gas

This report examines the initial steps that IRWM regions are taking in response to new requirements to address climate change vulnerabilities and consider greenhouse gas emissions in IRWM plans. Given our evolving understanding of climate change impacts and appropriate adaptation strategies, effectively integrating climate change into planning is a challenging task. This report seeks to learn from initial steps by IRWM regions in order to inform future guidance and support. It also identifies key considerations for DWR and IRWM regions in analyzing and adapting to climate change risks within an adaptive management framework. Specifically, this report seeks to: 1. Assess the manner and degree to which the climate change requirements in the 2010 IRWM Guidelines are met in Round 1 Proposition 84 Planning and Implementation grant proposals, and in recently approved IRWM plans 2. Assess current IRWM regional approaches to analyzing and adapting to climate change risks, in light of the overall goal to promote an adaptive management approach 3. Provide recommendations on key steps for DWR and IRWM regions to support the development of informative climate change analyses and mechanisms for adaptive management at regional and state levels This assessment is based on a review of the current IRWM climate change requirements, existing IRWM plans, and Planning and Implementation grant proposals funded in 2011. It is also informed by interviews conducted by DWR regional climate change specialists with representatives of IRWM regions regarding their plans to address climate change.

Climate Change and the Delta

University of California, Davis (UC Davis) | October 1st, 2016

Climate change amounts to a fast approaching, “new” stressor in the Sacramento–San Joaquin Delta system. In response to California’s extreme natural hydroclimatic

Climate change amounts to a fast approaching, “new” stressor in the Sacramento–San Joaquin Delta system. In response to California’s extreme natural hydroclimatic variability, complex water-management systems have been developed, even as the Delta’s natural ecosystems have been largely devastated. Climate change is projected to challenge these management and ecological systems in different ways that are characterized by different levels of uncertainty. Future precipitation changes are less certain, with as many climate models projecting wetter conditions as drier. Warmer temperatures will likely enhance evaporation and raise water temperatures. Consequently, climate change is projected to yield both more extreme flood risks and greater drought risks. Effects on the Delta ecosystem that are traceable to warming include sea level rise, reduced snowpack, earlier snowmelt and larger storm-driven streamflow, warmer and longer summers, warmer summer water temperatures, and water-quality changes. These changes and their uncertainties will challenge the operations of water projects and uses throughout the Delta’s watershed and delivery areas. Although the effects of climate change on Delta ecosystems may be profound, the end results are difficult to predict, except that native species will fare worse than invaders. Successful preparation for the coming changes will require greater integration of monitoring, modeling, and decision-making across time, variables, and space than has been historically normal.

Confirmation of Initial Incidental Take for Adult Delta Smelt for the 2018 Water Year

U.S. Fish and Wildlife Service (FWS) | January 4th, 2018

Coupling a spatiotemporally distributed soil water budget with stream-depletion functions to inform stakeholder-driven management of groundwater-dependent ecosystems

Water Resources Research, American Geophysical Union | November 12th, 2013

Groundwater pumping, even if only seasonal, may significantly impact groundwater-dependent ecosystems through increased streamflow depletion, particularly in semiarid and

Groundwater pumping, even if only seasonal, may significantly impact groundwater-dependent ecosystems through increased streamflow depletion, particularly in semiarid and arid regions. The effects are exacerbated, under some conditions, by climate change. In social sciences, the management of groundwater-dependent ecosystems is generally considered a “wicked” problem due to the complexity of affected stakeholder groups, disconnected legal frameworks, and a divergence of policies and science at the cross road between groundwater and surface water, and between ecosystems and water quality. A range of often simplified scientific tools plays an important role in addressing such problems. Here we develop a spatiotemporally distributed soil water budget model that we couple with an analytical model for stream depletion from groundwater pumping to rapidly assess seasonal impacts of groundwater pumping on streamflow during critical low flow periods. We demonstrate the applicability of the tool for the Scott Valley in Northern California, where protected salmon depend on summer streamflow fed by cool groundwater. In this example, simulations suggest that increased recharge in the period immediately preceding the critical low streamflow season, and transfer of groundwater pumping away from the stream are potentially promising tools to address ecosystem concerns, albeit raising difficult infrastructure and water trading issues. In contrast, additional winter recharge at the expense of later spring recharge, whether intentional or driven by climate may reduce summer streamflows. Comparison to existing detailed numerical groundwater model results suggests that the coupled soil water mass balance—stream depletion function approach provides a viable tool for scenario development among stakeholders, to constructively inform the search for potential solutions, and to direct more detailed, complex site-specific feasibility studies. The tool also identifies important field monitoring efforts needed to improve the understanding and quantification of site-specific groundwater-stream interactions.

Delta Conservation Adaptive Management Action Strategy

Delta Stewardship Council (Delta Council) | April 11th, 2019

Various efforts are ongoing to restore and enhance ecosystems in the Sacramento-San Joaquin Delta, Yolo Bypass, and Suisun Marsh (hereafter the Delta) that require suppor

Various efforts are ongoing to restore and enhance ecosystems in the Sacramento-San Joaquin Delta, Yolo Bypass, and Suisun Marsh (hereafter the Delta) that require support for adaptive management. Adaptive management is a science-based, structured approach to environmental decision making under uncertain conditions. Adaptive management emphasizes acquisition and use of new knowledge in natural resource management, leading to continuous iterative improvements in project planning, implementation, monitoring, and follow-up. Adaptive management is required for compliance with multiple regulatory processes, such as consistency with the Delta Plan and the Suisun Marsh Plan, but recent reviews have found that a full adaptive management cycle is rarely completed at either the project- or system-level in the Delta (Delta Independent Science Board 2016; Nagarkar and Raulund-Rasmussen 2016). To address this issue, the Delta Science Program initiated an effort to work with agency and stakeholder partners in the Delta to develop a comprehensive, science-based adaptive management approach to support achievement of Delta conservation goals. Conservation, as defined in the Delta Conservation Framework (Sloop et al. 2018), consists of efforts to protect, restore, and enhance ecosystems in the Delta. The Delta Conservation Adaptive Management Action Strategy is based on the Adaptive Management Framework outlined in the Delta Plan (Figure 1, Delta Stewardship Council 2013). 

Delta Conveyance Project Final Environmental Impact Report

California Department of Water Resources (DWR) | December 8th, 2023

Delta Conveyance Project: Modernizing California’s Water Infrastructure, Fast Facts 2024

California Department of Water Resources (DWR) | September 13th, 2023