San Francisco Bay

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. 

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.

Interagency Ecological Program Science Strategy 2020 – 2024: Investment Priorities for Interagency Collaborative Science

Interagency Ecological Program (IEP) | April 20th, 2019

The IEP Science Strategy is one of three organizing documents that together set the course for annual (IEP Annual Work Plan), 5-year (IEP Science Strategy), and 5

The IEP Science Strategy is one of three organizing documents that together set the course for annual (IEP Annual Work Plan), 5-year (IEP Science Strategy), and 5+ year (IEP Strategic Plan) organization planning for the Program. The Science Strategy is where the Science Management and Coordinators Teams articulate what they understand as the most pressing suite of subjects requiring additional data collection for management-relevant purposes for the IEP 9-Agency collective. The Science Strategy serves the additional purpose of providing a 5-year focus of planning effort to even-out short-term (annual) imperatives that change depending on mutable Agency directives.

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

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.

Introducing Time-Limited Permits to California’s Riparianism

University of California, Davis (UC Davis) | December 1st, 2023

Inventory of Recreation Facilities in the Sacramento-San Joaquin Delta (2015)

Delta Protection Commission (DPC) | February 21st, 2017

The Delta Protection Commission (Commission) is committed to national recognition of the Delta as a diverse, accessible, modern recreation and tourism destination. The Co

The Delta Protection Commission (Commission) is committed to national recognition of the Delta as a diverse, accessible, modern recreation and tourism destination. The Commission has compiled the 2015 Inventory of Recreation Facilities in the Sacramento-San Joaquin Delta which represents the current recreation resources in the Legal Delta and its adjacent areas. The Inventory is a reference for the Commission, State and local agencies, and recreation providers in planning, developing, and promoting the Delta as a unique recreation and tourism destination.

Investigation on the Feasibility of Developing Uniformwater Recycling Criteria ror Direct Potable Reuse

California State Water Resources Control Board (SWRCB) | December 1st, 2016

The population of California is projected to increase from 38 million to 50 million by the year 2049. This population increase will have a dramatic impact on the water ne

The population of California is projected to increase from 38 million to 50 million by the year 2049. This population increase will have a dramatic impact on the water needs of the State. To address this increased water need, the State will take a variety of actions as outlined in the Governor’s California Water Action Plan, first released in 2014 and recently updated in 2016 (CA Natural Resources Agency, 2016). One component of that plan is to increase the use of recycled water. The State Water Board has set a mandate of increasing the use of recycled water by 200,000 acre-foot per year (AFY) by 2020 and an additional 300,000 AFY by 2030. Although the use of recycled water for non-potable uses such as agricultural and landscape irrigation is already well established and has been regulated for decades in California, increasing the use of recycled water for both non-potable uses as well as a source of potable water (“potable reuse”) is important for the State to be able to meet this mandate. For example, groundwater replenishment (groundwater recharge), which is an indirect form of potable reuse, has the capacity to reuse 200,000 acre-feet of recycled water a year via just eight projects throughout California. Accordingly, the State Water Board revised and adopted uniform water recycling criteria for groundwater replenishment in 2014 and is in the process of establishing uniform water recycling criteria for the augmentation of surface water reservoirs used as a source of drinking water supply, which is another form of indirect potable reuse.

Irrigating Machinery on the Pacific Coast

Scientific American | December 17th, 1887

In offering the present paper to the Institution of Mechanical Engineers, the author does so with a tolerably complete knowledge of the very advanced practice in England

In offering the present paper to the Institution of Mechanical Engineers, the author does so with a tolerably complete knowledge of the very advanced practice in England in this class of machinery: and his purpose is mainly to explain the differences that have been called for by local circumstances in California. Character of the Country: The western or Pacific slope of the Sierra Nevada or coast range of mountains in California is very abrupt, the crests of the range being so near that the snow is visible from the coast during the whole year. Hundreds of streams cross this narrow country, falling either direct into the Pacific Ocean or into the great basin formed by the Sacramento and San Joaquin rivers. These two rivers. the largest in California, run in opposite directions nearly parallel with the coast and meet at the Bay of San Francisco forming ac ontinuous valley 400 miles long and from 50 to 100 miles wide. The small streams for the most part are fed by melting snow in the summer; and every gulch or canon has its rivulet or brook. They increase in volume until they pass into or through the hills at the foot of the mountain range; and there, unless of considerable size, they may wholly disappear in summer by percolation through the silt or by evaporation. Streams exposed to the torrid air which in summer sweeps across the sand deserts of Southern California are dried up with wonderful rapidity. The evaporation from Salt Lake, exposed to the same dry wind, is sometimes equal to half an inch per day. or 64 million tons of water. Not withstanding this great loss by evaporation, the quantity of water falling into the ocean on the coast of California has been estimated at 100 million cubic feet or 2 3/4 million tons per minute, enough, if distributed properly, to irrigate 25,000 square miles.