A functional flows approach to selecting ecologically relevant flow metrics for environmental flow applications

River Research and Applications (Wiley) | January 8th, 2020

A hydrological simulation dataset of the Upper Colorado River Basin from 1983 to 2019

Nature Portfolio (Springer Nature) | January 20th, 2022

The Upper Colorado River Basin (UCRB) is one of the most over-allocated basins in the world. It provides water for 40 million people in Colorado and downstream states of

The Upper Colorado River Basin (UCRB) is one of the most over-allocated basins in the world. It provides water for 40 million people in Colorado and downstream states of Arizona, California, Nevada, and Utah. However, the UCRB water capacity is decreasing as a combined result of climate change and anthropogenic activities. Understanding the dynamic of the UCRB water cycle is crucial for long-term and short-term water resources management.

A Review of Delta Fish Population Losses from Pumping Operations in the Sacramento-San Joaquin River Delta

Sacramento Regional County Sanitation District (RegionalSan) | January 30th, 2010

To reduce fish loss at the pumps, the state and federal water export facilities operate facilities which are designed to salvage fish from the water and return them to th

To reduce fish loss at the pumps, the state and federal water export facilities operate facilities which are designed to salvage fish from the water and return them to the Delta. Fish facilities include the SWP Skinner Fish Protection Facility and CVP Tracy Fish Collection Facility. The fish facilities utilize two sets of louvers to prevent fish from entering further into water project operations and ultimately the powerful pumps. The louvers concentrate fish so that they can be removed prior to the water diversions. However, these fish salvage operations are inefficient, as high numbers of fish are lost due to predation in the waterways leading to the fish facilities, and the louvers are inefficient.

A Twenty-First-Century California Observing Network for Monitoring Extreme Weather Events

American Meteorological Society (AMS) | August 27th, 2013

During Northern Hemisphere winters, the West Coast of North America is battered by extratropical storms. The impact of these storms is of paramount concern to California,

During Northern Hemisphere winters, the West Coast of North America is battered by extratropical storms. The impact of these storms is of paramount concern to California, where aging water supply and flood protection infrastructures are challenged by increased standards for urban flood protection, an unusually variable weather regime, and projections of climate change. Additionally, there are inherent conflicts between releasing water to provide flood protection and storing water to meet requirements for the water supply, water quality, hydropower generation, water temperature and flow for at-risk species, and recreation. To improve reservoir management and meet the increasing demands on water, improved forecasts of precipitation, especially during extreme events, are required. Here, the authors describe how California is addressing their most important and costliest environmental issue-water management-in part, by installing a state-of-the-art observing system to better track the area's most severe wintertime storms.

Accounting for Water "Wasted to the Sea"

University of California, Davis (UC Davis) | April 19th, 2018

Freshwater outflow from the Sacramento–San Joaquin Delta is a contentious management issue. Once mixed with salt water of San Francisco Bay, outflow is often characteri

Freshwater outflow from the Sacramento–San Joaquin Delta is a contentious management issue. Once mixed with salt water of San Francisco Bay, outflow is often characterized as having no value for urban and agricultural water supply, and thus “wasted to the sea.” In the July issue of San Francisco Estuary and Watershed Science, Cloern et al. (2017) showed how outflow from the Delta provides multiple and diverse benefits to the San Francisco estuary. Rather than being “wasted,” this outflow improves ecosystem conditions and water quality, and reduces wastewater treatment costs. The Cloern et al. (2017) essay highlights the importance of considering the multiple benefits of water as it moves within and out of the Delta. To do this, however, California needs a better water accounting system. In this report, we present an alternative approach. For the period 1980–2016, we assign inflow to the Delta to four categories: 1. Water used for diversions, 2. Outflow needed to meet salinity standards for diversions, 3. Outflow to meet ecosystem regulations, and 4. Water that results in outflow because of a lack of capacity for diversion. This approach highlights that much of the outflow from the Delta — particularly during dry periods — achieves multiple economic and environmental benefits and is hardly “wasted to the sea.”

Adaptability and adaptations of California’s water supply system to dry climate warming

Climactic Change (Springer) | November 27th, 2007

Economically optimal operational changes and adaptations for California’s water supply system are examined for a dry form of climate warming (GFDL CM2.1 A2) with year 2

Economically optimal operational changes and adaptations for California’s water supply system are examined for a dry form of climate warming (GFDL CM2.1 A2) with year 2050 water demands and land use. Economically adaptive water management for this climate scenario is compared to a similar scenario with the historical climate. The effects of population growth and land use alone are developed for comparison. Compared with the historic hydrology, optimized operations for the dry climate warming scenario raise water scarcity and total operation costs by $490 million/year with year 2050 demands. Actual costs might be somewhat higher where non-economic objectives prevail in water management. The paper examines the economical mix of adaptation, technologies, policies, and operational changes available to keep water supply impacts to such modest levels. Results from this screening model suggest promising alternatives and likely responses and impacts. Optimized operations of ground and surface water storage change significantly with climate. Dry-warm climate change increases the seasonal storage range of surface reservoirs and aquifers. Surface reservoir peak storage usually occurs about a month earlier under dry-warm climate change.

Adapting to Climate Change: Catching and Moving Water from Big Storms

California Department of Water Resources (DWR) | February 15th, 2024

Addendum to the State Water Project and Central Valley Project Drought Contingency Plan

California Department of Water Resources (DWR) | August 31st, 2022

This Addendum includes current hydrologic conditions, plus updates on the following: operations status and the latest SWP and CVP (collectively referred to as Projects) o

This Addendum includes current hydrologic conditions, plus updates on the following: operations status and the latest SWP and CVP (collectively referred to as Projects) operations forecasts; species status; and known WY 2022 drought actions.

Addendum to the State Water Project and Central Valley Project Drought Contingency Plan

California Department of Water Resources (DWR) | July 29th, 2022

This Addendum includes current hydrologic conditions, plus updates on the following: operations status and the latest SWP and CVP (collectively referred to as Projects) o

This Addendum includes current hydrologic conditions, plus updates on the following: operations status and the latest SWP and CVP (collectively referred to as Projects) operations forecasts; species status; and known WY 2022 drought actions.

Advancing Hydro-Economic Optimization to Identify Vulnerabilities and Adaptation Opportunities in California’s Water System

California Natural Resources Agency (CNRA) | August 27th, 2018

Long-term shifts in the timing and magnitude of reservoir inflows will affect water supply reliability in California. Hydro-economic models can help explore climate chang

Long-term shifts in the timing and magnitude of reservoir inflows will affect water supply reliability in California. Hydro-economic models can help explore climate change concerns by identifying system vulnerabilities and adaptation strategies for statewide water operations. This work contributes a new open-source limited foresight implementation of the CALVIN model, a hydro-economic model including roughly 90% of California’s urban and agricultural water demands. The model includes the ability to determine water allocations on an annual basis without knowledge of future availability, and to efficiently evaluate ensembles of streamflow projections representing a range of possible future climates. We then assess the vulnerability of the statewide system to changes in total annual runoff and the fraction of runoff occurring during winter, which primarily depends on temperature. Results are analyzed with a focus on adaptation strategies, aided by the economic representation of water demand in the model. These strategies include changes to reservoir operating policies, and conveyance and storage expansion. As water availability decreases, model results show quadratic increases in shortage cost, and corresponding increases in the marginal costs of adaptation strategies and environmental flow constraints. Reservoirs adapt to warmer climates by increasing average storage levels in winter and routing excess runoff to downstream reservoirs with available capacity. Both small and large changes to reservoir operations were observed compared to historical hydrology, showing that no single operating strategy achieves optimality for all reservoirs. Increasing the fraction of winter flow causes small increases in total shortage cost, indicating the ability to manage a changing hydrologic regime with adaptive reservoir operations. The results of this project improve estimates of the cost of climate change to California’s water system under a range of future conditions and highlight adaptation strategies that minimize costs of increased hydrologic variability.