Report on Feasibility of Feather River Project and Sacramento-San Joaquin Delta Diversion Projects Proposed as Features of the California Water Plan

California Department of Water Resources (DWR) | May 17th, 1951

Responses and impacts of atmospheric rivers to climate change

Nature Portfolio (Springer Nature) | March 9th, 2020

Atmospheric rivers (ARs) are characterized by intense moisture transport, which, on landfall, produce precipitation which can be both beneficial and destructive. ARs in C

Atmospheric rivers (ARs) are characterized by intense moisture transport, which, on landfall, produce precipitation which can be both beneficial and destructive. ARs in California, for example, are known to have ended drought conditions but also to have caused substantial socio-economic damage from landslides and flooding linked to extreme precipitation. Understanding how AR characteristics will respond to a warming climate is, therefore, vital to the resilience of communities affected by them, such as the western USA, Europe, East Asia and South Africa. In this Review, we use a theoretical framework to synthesize understanding of the dynamic and thermodynamic responses of ARs to anthropogenic warming and connect them to observed and projected changes and impacts revealed by observations and complex models. Evidence suggests that increased atmospheric moisture (governed by Clausius–Clapeyron scaling) will enhance the intensity of AR-related precipitation — and related hydrological extremes — but with changes that are ultimately linked to topographic barriers. However, due to their dependency on both weather and climate-scale processes, which themselves are often poorly constrained, projections are uncertain. To build confidence and improve resilience, future work must focus efforts on characterizing the multiscale development of ARs and in obtaining observations from understudied regions, including the West Pacific, South Pacific and South Atlantic.

Review of Science Used to Estimate Water Supply Reliability Involving the Delta

Delta Stewardship Council (Delta Council) | April 3rd, 2018

Review of Water Supply Reliability Estimation Related to the Sacramento-San Joaquin Delta

Delta Stewardship Council (Delta Council) | June 16th, 2022

Ridging associated with drought in western and southwestern United States: characteristics, trends and predictability

American Meteorological Society (AMS) | April 1st, 2020

Persistent winter ridging events are a consistent feature of meteorological drought across the western and southwestern United States. In this study, a ridge detection al

Persistent winter ridging events are a consistent feature of meteorological drought across the western and southwestern United States. In this study, a ridge detection algorithm is developed and applied on daily geopotential height anomalies to track and quantify the diversity of individual ridge characteristics (e.g., position, frequency, magnitude, extent, and persistence). Three dominant ridge types are shown to play important, but differing, roles for influencing the location of landfalling atmospheric rivers (ARs), precipitation, and subsequently meteorological drought. For California, a combination of these ridge types is important for influencing precipitation deficits on daily through seasonal time scales, indicating the various pathways by which ridging can induce drought. Furthermore, both the frequency of ridge types and reduced AR activity are necessary features for explaining drought variability on seasonal time scales across the western and southwestern regions. The three ridge types are found to be associated in different ways with various remote drivers and modes of variability, highlighting possible sources of subseasonal-to-seasonal (S2S) predictability. A comparison between ridge types shows that anomalously large and persistent ridging events relate to different Rossby wave trains across the Pacific with different preferential upstream locations of tropical heating. For the “South-ridge” type, centered over the Southwest, a positive trend is found in both the frequency and persistence of these events across recent decades, likely contributing to observed regional drying. These results illustrate the utility of feature tracking for characterizing a wider range of ridging features that collectively influence precipitation deficits and drought.

Risk-Informed Future Climate Scenario Development for the State Water Project Delivery Capability Report

California Department of Water Resources (DWR) | August 24th, 2023

This report introduces and documents an extensive effort undertaken by the California Department of Water Resources (DWR) to develop risk-informed future climate scenario

This report introduces and documents an extensive effort undertaken by the California Department of Water Resources (DWR) to develop risk-informed future climate scenarios for the State Water Project (SWP) Delivery Capability Report (DCR), a report issued by the SWP every two years. These reports present DWR’s analysis of the SWP system and planning information for users of SWP water. The analysis provides information about how climate change, regulatory, and operational considerations affect SWP delivery capability. Specifically, the report must provide “…under a range of hydrologic conditions, the then existing overall delivery capability of the project facilities and the allocation of that capacity to each contractor. The range of hydrologic conditions shall include the historic extended dry cycle and long-term average.” (Settlement Agreement 2003).

Root Creek Water District Groundwater Sustainability Agency Groundwater Sustainability Plan

Root Creek Water District | November 11th, 2019

Root Creek Water District Groundwater Sustainability Plan

Root Creek Water District | March 20th, 2023

Safe Clean Water Water for Los Angeles County Residents

Los Angeles County Department of Public Works (LACDPW) | November 7th, 2017

We live in a water-scarce area, and forces outside of our control can threaten our local water resources, including lakes, rivers and beaches. LA Count

We live in a water-scarce area, and forces outside of our control can threaten our local water resources, including lakes, rivers and beaches. LA County residents rely heavily on imported water from the Sierra Mountains, the Central Valley and even from states as far away as Colorado. Climate change is causing more and more extreme weather conditions, making these remote sources more unreliable . The impacts of the recent five-year drought were widely felt here. Rainfall is an essential, local source of LA’s water . Rain runs through local rivers, creeks and streams and can be absorbed underground, replenishing groundwater, which is a local source of drinking water. However, because so much of our region is paved over, when we do experience heavy rain, too much of that precious water is lost to the ocean before we can capture it for use. Our local water resources are also threatened by toxins and pollution as stormwater runs through streets and over-paved areas into our rivers, creeks and streams. Pollution flows onto our beaches and into the ocean, posing a public health risk and harming marine life.

Salinas River Watershed Area Salt Modeling

California Central Coast Regional Water Quality Control Board (CCRWQCB) | November 13th, 2015

Tetra Tech supported EPA Region 9 and the Central Coast Regional Water Quality Control Board (CCRWQCB) for an assessment of salt impairments and development of a

Tetra Tech supported EPA Region 9 and the Central Coast Regional Water Quality Control Board (CCRWQCB) for an assessment of salt impairments and development of a salt mass balance in the Lower Salinas River and Reclamation Canal watersheds. This effort can inform development of salt-related TMDLs by the CCRWQCB and a salt and nutrient management plan for the Salinas Valley aquifers. Three reaches have reported 2010 303(d) listings for salt-related impairments in these watersheds including impairments due to chloride, sodium, electrical conductivity, and total dissolved solids – Lower Salinas River, Santa Rita Creek, and Alisal Creek. This report provides data analysis and a literature review (Sections 1 through 5), development of a water and salt mass balance tool (Sections 6 through 8), and salt source assessment (Section 9). The results of the analysis provide a strong foundation for assessing salt sources and understanding salt mass balance in the study area, but can be improved with refined representation of cropland locations, rotations, and irrigation practices.