San Joaquin River

Integrated Management of Delta Stressors: Institutional and Legal Options

Public Policy Institute of California (PPIC) | April 22nd, 2013

Despite some recent progress, the current institutional landscape for regulation and management of stressors in the in the Sacramento–San Joaquin Delta is highly fragme

Despite some recent progress, the current institutional landscape for regulation and management of stressors in the in the Sacramento–San Joaquin Delta is highly fragmented. A modest but powerful set of institutional changes can help produce better environmental outcomes while containing management costs—which are likely to exceed several hundred million dollars annually. This report lays out proposals for institutional reform.

Integrated simulation of consumptive use and land subsidence in the Central Valley, California, for the past and for a future subject to urbanization and climate change

U.S. Geological Survey (USGS) | October 17th, 2010

Competition for water resources is growing throughout California, particularly in the Central Valley where about 20% of all groundwater used in the United States of Ameri

Competition for water resources is growing throughout California, particularly in the Central Valley where about 20% of all groundwater used in the United States of America is consumed for agriculture and urban water supply. Continued agricultural use coupled with urban growth and potential climate change would result in continued depletion of groundwater storage and associated land subsidence throughout the Central Valley. For 1962–2003, an estimated 1230 hectametres (hm3) of water was withdrawn from fine-grained beds, resulting in more than three metres (m) of additional land subsidence locally. Linked physically-based, supply-constrained and demand-driven hydrological models were used to simulate future hydrologic conditions under the A2 climate projection scenario that assumes continued “business as usual” greenhouse gas emissions. Results indicate an increased subsidence in the second half of the twenty-first century. Potential simulated land subsidence extends into urban areas and the eastern side of the valley where future surface-water deliveries may be depleted.

Integrated Water Operations in California: Hydropower, Overdraft, and Climate Change

University of California, Davis (UC Davis) | July 16th, 2015

Several management and climate cases are evaluated with the updated CALVIN, a hydro-economic optimization model of California’s inter-tied water supply infrastructure.

Several management and climate cases are evaluated with the updated CALVIN, a hydro-economic optimization model of California’s inter-tied water supply infrastructure. Updates to the CALVIN model include new projected 2050 agricultural target demands and scarcity penalties, improvements to network-flow representation, especially agricultural, urban, and wildlife refuge demands, and extended surface and ground water hydrology, now covering an 82-year historical inflow hydrology. A new energy price scheme is applied to CALVIN, which incorporates hourly energy price variations into monthly CALVIN operations. Using one constant average price for a month underestimates hydropower revenue and overestimates pumping costs. Hourly-varying moving average prices improved representation of hydropower revenue without creating significant scarcities to agricultural and urban water users. Effects of ending long-term groundwater overdraft in the Central Valley are evaluated with several management cases using CALVIN. The cases include effects of Delta outflow and Delta exports from a “no overdraft” policy. The least cost overdraft that minimizes groundwater pumping and scarcity costs is calculated for the 82-year period. Prohibiting Delta exports result in severe water scarcities south of the Delta. Water operations are more economical when overdraft is ended with adaptations, such as more Delta exports, increased groundwater banking, and water trades, than historical operations with overdraft. Finally, climate change effects under a warmer and drier climate scenario are studied and results are compared to historical hydrology. A drier and warmer climate shifts the timing and magnitude of stream flows. Spring snowmelt decreases and winter flows increase. Modelled reduction in rim inflows averages about 28%. This warmer-drier climate increases water scarcities, but adverse effects can be diminished with water sales, higher Delta exports, more conjunctive use, and wastewater recycling. 

Intensification of hydrological drought in California by human water management

American Geophysical Union (AGU) | January 25th, 2017

Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity

Conservation Physiology (Society of Experimental Biology) | December 10th, 2020

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allop

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allopatric upstream spawning habitat of the Central Valley (CV) population connects with the sympatric rearing grounds via relatively low salinity waters, whereas the San Pablo (SP) population must pass through the relatively high-salinity Upper SFE to reach its allopatric downstream spawning habitat. We hypothesize that if migration through SFE salinities to SP spawning grounds is more challenging for adult CV than SP splittail, then salinity tolerance, osmoregulatory capacity, and metabolic responses to salinity will differ between populations. Osmoregulatory disturbances, assessed by measuring plasma osmolality and ions, muscle moisture and Na+-K+-ATPase activity after 168 to 336 h at 11 salinity, showed evidence for a more robust osmoregulatory capacity in adult SP relative to CV splittail. While both resting and maximum metabolic rates were elevated in SP splittail in response to increased salinity, CV splittail metabolic rates were unaffected by salinity. Further, the calculated difference between resting and maximum metabolic values, aerobic scope, did not differ significantly between populations. Therefore, improved osmoregulation came at a metabolic cost for SP splittail but was not associated with negative impacts on scope for aerobic metabolism. These results suggest that SP splittail may be physiologically adjusted to allow for migration through higher-salinity waters. The trends in interpopulation variation in osmoregulatory and metabolic responses to salinity exposures support our hypothesis of greater salinity-related challenges to adult CV than SP splittail migration and are consistent with our previous findings for juvenile splittail populations, further supporting our recommendation of population-specific management.

Interactions between urban water policy, residential irrigation, and plant & bird diversity in the Fresno-Clovis Metro Area

Nature Portfolio (Springer Nature) | August 11th, 2011

Ecological theory has begun to incorporate humans as part of coupled socio-ecological systems. Modern urban development provides an excellent laboratory to examine the in

Ecological theory has begun to incorporate humans as part of coupled socio-ecological systems. Modern urban development provides an excellent laboratory to examine the interplay among socio-ecological relationships. Urban land and water management decisions result from dynamic interactions between institutional, individual and ecological factors. Landscaping and irrigation at any particular residence, for example, is a product of geography, hydrology, soil, and other local environmental conditions, the homeowners’ cultural preferences, socioeconomic status, identity construction, neighborhood dynamics, as well as zoning laws, market conditions, city policies, and county/state/federal government regulations. Since land and water management are key determinants of habitat for other species, urban biodiversity is strongly driven by the outcome of interactions between these variables. This study addresses the significance of water as a key variable in the Fresno-Clovis Metropolitan Area (FCMA), shaping current patterns of landscape and water use, at a time when the city of Fresno is installing meters as a regulatory tool to conserve water. We combine data from a citizen science bird monitoring project, field surveys of trees, and mail surveys of residents to address interactions among key components of the urban socioecological system.

Interagency Ecological Program Science Strategy: Needs for near-term science in five areas of emphasis

Interagency Ecological Program (IEP) | March 4th, 2016

The mission of the Interagency Ecological Program (IEP) is to provide and integrate relevant and timely ecological information for management of the Bay-Delta ecosystem a

The mission of the Interagency Ecological Program (IEP) is to provide and integrate relevant and timely ecological information for management of the Bay-Delta ecosystem and the water that flows through it. This is accomplished through collaborative and scientifically sound monitoring, research, modeling, and synthesis efforts for various aspects of the aquatic ecosystem. Building on the IEP Strategic Plan, which identifies the long-term goals and strategies to be implemented by the IEP to achieve its mission, the IEP Science Strategy provides direction to interagency science used to inform the management and ecological interests of IEP agencies in the near-term, and is one of a number of inputs used to shape the IEP Annual Work Plans. While the IEP Strategic Plan states that the Science Strategy be drafted for a 3-5 year horizon, a shorter 2-year timeframe for this first IEP Science Strategy has been adopted to allow for a more flexible internal development and review process, as well as feedback from the Bay-Delta research and stakeholder community.

Interagency Ecological Program’s Ability to Provide Science Supporting Management of the Delta

Delta Stewardship Council (Delta Council) | November 15th, 2019

Interbasin water transfers in the United States and Canada

Nature Portfolio (Springer Nature) | January 13th, 2023

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as well as basins downstream of these water transfers. The lack of comprehensive data identifying and describing IBTs inhibits understanding of the role IBTs play in supplying water for society, as well as their collective hydrologic impact. We develop three connected datasets inventorying IBTs in the United States and Canada, including their features, geospatial details, and water transfer volumes. We surveyed the academic and gray literature, as well as local, state, and federal water agencies, to collect, process, and verify IBTs in Canada and the United States. Our comprehensive IBT datasets represent all known transfers of untreated water that cross subregion (US) or subdrainage area (CA) boundaries, characterizing a total of 641 IBT projects. The infrastructure-level data made available by these data products can be used to close water budgets, connect water supplies to water use, and better represent human impacts within hydrologic and ecosystem models.

Interpreting Water Supply Forecasts

U.S. Bureau of Reclamation (USBR) | January 24th, 2012

For each Central Valley Project (CVP) allocation announcement, two forecasts are issued for each contract type by location within the CVP. Unless otherwise specified, all

For each Central Valley Project (CVP) allocation announcement, two forecasts are issued for each contract type by location within the CVP. Unless otherwise specified, all runoff forecasts are based on runoff volumes that would occur naturally without any upstream influences. For the February through May period, the runoff volume estimates are based on the observed inflow to date and current snow pack measurements made at the end of each preceding month. Water users need to know what the different forecasts represent if they are to use the information appropriately when making operational decisions. Following are explanations of each of the forecasts.