California Central Valley Project Research Articles

Analysis of future climate change impacts on snow distribution over mountainous watersheds in Northern California by means of a physically-based snow distribution model

The impacts of climate change on snow distribution through the 21st century were investigated over three mountainous watersheds in Northern California by means of a physically-based snow distribution model. The future climate conditions during a 90-year future period from water year 2010 to 2100 were obtained from 13 future climate projection realizations from two GCMs (ECHAM5 and CCSM3) based on four SRES scenarios (A1B, A1FI, A2, and B1). The 13 future climate projection realizations were dynamically downscaled at 9 km resolution by a regional climate model. Using the downscaled variables based on the 13 future climate projection realizations, snow distribution over the Feather, Yuba, and American River watersheds (FRW, YRW, and ARW) was projected by means of the physically-based snow model. FRW and YRW watersheds cover the main source areas of the California State Water Project (SWP), and ARW is one of the key watersheds in the California Central Valley Project (CVP). SWP and CVP are of great importance as they provide and regulate much of the California's water for drinking, irrigation, flood control, environmental, and hydro-power generation purposes. Ensemble average snow distribution over the study watersheds was calculated over the 13 realizations and for each scenario, revealing differences among the scenarios. While the snow reduction through the 21st century was similar between A1B and A2, the snow reduction was milder for B1, and more severe for A1FI. A significant downward trend was detected in the snowpack over nearly the entire watershed areas for all the ensemble average results.

Assessing reservoir operations risk under climate change

Risk‐based planning offers a robust way to identify strategies that permit adaptive water resources management under climate change. This paper presents a flexible methodology for conducting climate change risk assessments involving reservoir operations. Decision makers can apply this methodology to their systems by selecting future periods and risk metrics relevant to their planning questions and by collectively evaluating system impacts relative to an ensemble of climate projection scenarios (weighted or not). This paper shows multiple applications of this methodology in a case study involving California's Central Valley Project and State Water Project systems. Multiple applications were conducted to show how choices made in conducting the risk assessment, choices known as analytical design decisions, can affect assessed risk. Specifically, risk was reanalyzed for every choice combination of two design decisions: (1) whether to assume climate change will influence flood‐control constraints on water supply operations (and how), and (2) whether to weight climate change scenarios (and how). Results show that assessed risk would motivate different planning pathways depending on decision‐maker attitudes toward risk (e.g., risk neutral versus risk averse). Results also show that assessed risk at a given risk attitude is sensitive to the analytical design choices listed above, with the choice of whether to adjust flood‐control rules under climate change having considerably more influence than the choice on whether to weight climate scenarios.

Managing Water Diversion from Canada to the United States

Water is increasingly a major political issue as scarcity of resource grips several societies, especially in developing countries where agriculture is responsible for about 80 percent of water consumptive use. However, western nations are not immune to water tensions, for instance in Greece, Spain, Italy, or western United States, where available water is being exploited to limit: Colorado no longer reaches sea, and growing debates are emerging as to whether water should be allocated to thirsty cities or to agriculture; whether public funds should be invested again to increase resource or demand management implemented; and whether water could be imported from far away.These questions are increasingly relevant: consumption patterns of water in western US are clearly not sustainable. Given technology available today, massive water transfers could only come from Canada. There have been several mooted projects in this vein, mostly in 1960s and 1970s. Should Canadians worry about water exports to United Sates, especially in frame of NAFTA? Or is climate change going to be decisive factor in debate?THE ADVENT OF WATER ADDICTION IN THE WESTERN UNITED STATESWater is a key ingredient in fabric of western American society, as has been well studied by Donald Worster.1 west is not completely waterscarce, for several mighty rivers flow in region, mainly fed by snow and glaciers from Rockies; but it definitely is a semi-arid region, compelling all societies living there before industrial revolution to adapt to water scarcity. Early 20th century American society, empowered by industrial age, decided to harness rivers and aquifers. Technology enabled American society to eliminate water scarcity burden and developed illusion that technology would always bring about a solution to growing water needs. What nature does not yield freely, humanity should refashion to better suit human needs.... Nature has no greater purpose than to serve Man, and Man has no greater purpose than to work land and take his place in productive cycle.2 Wendy Nelson Espeland also clearly depicted representation that developed at time that all water flowing unused to ocean was a wasted resource, and that rivers needed to be tamed and harnessed to be put to use. President Franklin Roosevelt declared in 1935, when inaugurating Boulder Dam, that the mighty waters of Colorado were running unused to sea. Today we translate them into a great national possession.2This idea is still very much alive today. Much of contemporary culture of American Southwest is based on denying its desertness.... In a subdivision being built to south [of Las Vegas], Paseo Verde Parkway and Val Verde Road intersect in Green Valley Ranch. concept of green, like sod lawns, was an imported fantasy.4 Technology can make up for water scarcity and water must be used so as to develop western resources: The rural Western ethic is that all wealth comes out of ground, either as grass growing or as minerals being mined.... So fact that today's reclamation projects-such as Garrison, CUP, Animas-La Plata-cost a few million dollars for each farmer they put on land, doesn't cause their proponents to blink. That, they say, is price society pays for creating stuff of wealth. Without it and other industries based on earth, there is nothing.5EARLY MASSIVE WATER TRANSFER PROJECTSMassive water transfers were first built in eastern United States in 1847 with Croton aqueduct for New York City and 1900 Chicago diversion. As early as 1906, water transfers began being built in west, with a 46 km-long canal from St. Mary River in Montana to Milk River, triggering a severe dispute with Canada that forced United States to negotiate 1909 boundary waters treaty. Other projects soon followed: Los Angeles aqueduct in 1913, Hetch Hetchy water supply (1934), Colorado River aqueduct (1941), Ail-American Canal (1942), and California central valley project (1951). …

“Their Sleep Is To Be Desecrated”: California's Central Valley Project and the Wintu People of Northern California, 1938-1943

The morning of July 14, 1944, was intended to be a moment of celebration for the City of Redding, California. Secretary of the Interior Harold L. Ickes had been scheduled to arrive in the booming city to dedicate Shasta Dam, a national reclamation project of great pride to local citizens and construction workers. Just days prior, however, the dedication ceremony had been canceled due to the inability of Ickes to leave Washington D.C.. Instead, a small group of U.S. Bureau of Reclamation (BOR) officials, Sacramento Municipal Utility District (SMUD) officials, and local city officials quietly gathered within the dam's $19,400,000 power plant. A BOR official flipped a switch to start one of the plant's two massive generators, sending a surge of 120,000 watts of hydroelectricity into California's transmission lines and the Pacific, Gas, and Electric (PG&E) distribution system. This energy would fuel the West's war industries and the federal defense effort in World War II. Though without fanfare, the switching event signaled the official start of commercial production of power from the world's second largest dam and keystone of the Central Valley Project (CVP). From Washington, D.C., the event was heralded by BOR Commissioner Harry W. Bashore as “a milestone in the fulfillment of visions Californians have had for nearly 100 years.”2

Riverine based eco-tourism: Trinity River non-market benefits estimates

SUMMARY California's Central Valley Project (CVP) was approved by voters in a statewide referendum in 1933. CVP referendum approval initiated funding for construction of important water development projects that had far reaching effects on regional water supplies. The construction of Trinity Dam in 1963 and the subsequent transbasin diversion of Trinity River flow was one of several CVP projects that had noteworthy adverse environmental and regional economic impacts. The Trinity River is the largest tributary of the Klamath River, and has its headwaters in the Trinity Alps of north-central California. After the construction of Trinity Dam in 1963, 90% of the Trinity River flow at Lewiston was moved to the Sacramento River via the Clear Creek Tunnel. Before 1963, the Trinity River was a major recreation resource of Northern California. The loss of stream flow has had a marked adverse impact on Trinity River-related recreation activities and the size and robustness of Trinity River salmon, steelhead, shad, and sturgeon runs. Trinity River water produces hydropower during its transit via Bureau of Reclamation canals and pumps to the northern San Joaquin Valley, where it is used for irrigated agriculture. The benefits provided by Trinity River instream flow-related environmental amenities were estimated with the travel cost method (TCM). Trinity River non-market benefits are about $406 million per annum, while the social cost of sending water down the Trinity River ranges from $17 to $42 million per annum, depending on the exact flow. We also discuss the relative magnitude of Trinity River survey data contingent value method (CVM) benefits estimates.

Optimization of Value of CVP's Hydropower Production

CVPOP is a nonlinear programming model for the optimization of the multi‐month operation of the hydropower system of the California Central Valley Project (CVP). CVPOP includes the dependence of energy values within each month on the capacity factor of the generating unit, avoiding the simplification of assuming constant monthly or yearly values as is common in other models. The model also includes contractual energy and capacity constraints which are nonlinear because of the powerplants' variable head performance curves (capability in MW and energy production rate in kWh per unit release versus reservoir storage). An example illustrates the difference between the values of the energy generated with operations schedules obtained using different objective functions.

Dynamic model for multireservoir operation

This paper presents a methodology to obtain optimal reservoir operation policies for a large‐ scale reservoir system. The model yields medium‐term (one‐year‐ahead) optimal release policies that allow the planning of activities within the current water year, with the possibility of updating preplanned activities to account for uncertain events that affect the state of the system. River flows are characterized as a multivariate autoregressive process and are forecasted using maximum likelihood estimators. The solution method is a sequential dynamic decomposition algorithm that keeps computational requirements and dimensionality problems at low levels. The model maximizes the system annual energy generation while satisfying constraints imposed on the operation of the reservoir network. Several alternative versions of the model are also presented, which can be used under different assumptions. The model is applied to a large‐scale multireservoir system, the northern portion of the California Central Valley Project. The optimal release policies show a potential increase in the system total annual energy with respect to heuristic schedules currently in use.

Multipurpose reservoir operation: 1. Monthly model for a single reservoir

The Becker and Yeh monthly operation model, which maximizes the energy output of a reservoir system, has been extended to allow for maximization of both water and energy from the system. The model is a combination of parametric linear programming (used for month-by-month optimization) and dynamic programming (used for optimization over the 1-yr. operation period). The resulting operating policy is updated as new monthly inflow forecasts become available, thus incorporating the stochasticity of inflows. An iterative procedure is used to reduce the computation time and computer storage requirements. This efficiency allows the use of minicomputers which are less expensive than mainframe computers. The use of the model is illustrated for the Shasta reservoir (California Central Valley Project).

Multipurpose reservoir operation: 2. Daily operation of a multiple reservoir system

The short-term control of reservoir systems usually calls for numerous updates of the operating policy because of the uncertainties associated with the forecast of inflow. This paper presents and illustrates a daily operation model for maximization of monthly water and energy output from a system of two parallel reservoirs. The model uses optimum monthly water and energy contract levels obtained from the monthly release policy. These contract levels are adjusted to allow for differences between the daily and monthly forecast of inflow. The model is developed using a minicomputer to provide an inexpensive tool for updating purposes. The model is applied to the Shasta and Folsom reservoirs of the California Central Valley Project with computation time requirements of less than 2 min.

Reservoir Operation: Choice of Objective Functions

An efficient algorithm for the real‐time monthly operation of a multipurpose reservoir is presented. The model is a combination of linear programming (used for month‐by‐month optimization) and dynamic programming (used for annual optimization). The use of parametric linear programming, minimum required beginning‐of‐month storages, and an iterative solution procedure result in low computer time and computer storage requirements. Low computer storage requirements allow the model to be run on minicomputers. Water and energy maximization, water and energy maximization with flood control considerations, and water and energy maximization for peak demand months are considered. Thus, the model provides the reservoir operator with different choices for annual optimization. The model is applied to Folsom reservoir of the California Central Valley Project and the results are discussed.

Reservoir Operation by Linear and Dynamic Programming

The operation of reservoirs often requires frequent updating of the results of the operation model. This is mainly because of errors involved in forecasting the natural inflows to the reservoirs or demands for water and energy or both. Current models used for operation usually require the use of large computers because of their core‐storage and computation‐time requirements. Frequent use of such models for the purpose of updating will often result in high computation cost and usually involves long turnaround times. This paper presents an efficient algorithm for the monthly operation of a system of two parallel multipurpose reservoirs that is solved with a minicomputer. The operation model is applied to Shasta and Folsom reservoirs of the California Central Valley Project, and the results are reviewed.

Optimal Operation of a Multiple Reservoir System

Author(s): Marino, Miguel A; Loaiciga, Hugo A | Abstract: This report presents a methodology to obtain optimal reservoir operation policies for a large-scale reservoir system. The model maximizes the system annual energy generation while satisfying constraints imposed on the operation of the reservoir network. The model incorporates the stochasticity of river flows and keeps future operating schedules up-to-date with the actual realization of those random variables. It yields medium-term (one-year ahead) optimal release policies that allow the planning of activities within the current water year, with the possibility of updating preplanned activities to account for uncertain events that affect the state of the system. The solution approach is a sequential dynamic decomposition algorithm that keeps computational requirements and dimensionality problems at low levels. The model is applied to a nine-reservoir portion of the California Central Valley Project and the results are compared with those from conventional operation methods currently in use, showing that the use of the model can improve the levels of energy production (about 30 percent increase) while the optimal release policies meet satisfactorily all other functions of the reservoir system. Sensitivity analysis is conducted to assess the optimality of the solutions and several alternative formulations of the model are developed and tested, the results showing the robustness of the optimal policies to the choice of model.

Reservoir management: A reliability programming approach

A reliability programming model is developed to determine the optimum monthly releases from a multipurpose reservoir. The model is based on chance‐constrained linear programming (CCLP) and dynamic programming (DP). The flood and drought reliabilities are represented in the CCLP in the form of chance constraints. These reliabilities are varied parametrically from their minimum required levels to their maximum possible values. The trade‐offs between flood and drought reliabilities are made using a forward two‐dimensional DP routine. The model does not require equal flood and/or drought reliabilities during the year. Folsom reservoir of the California Central Valley Project is modeled to demonstrate the use of this reliability programming approach. The resulting operation policy shows high reliabilities of flood and drought during winter and summer months, respectively. The variable risk levels avoid unnecessary releases during summer (for flood protection) and unnecessary storage of water during winter (for drought protection).

Multiobjective analysis of multireservoir operations

The objective of the study reported herein is to develop practical procedures for the analysis of a multiple purpose, multiple facility reservoir system to guide real time decisions concerning the optimal operation of the system. Application is made to the California Central Valley Project (CVP). The five purposes (benefits), treated as objectives here in the multiobjective optimization, include (1) hydropower production, (2) fish protection, (3) water quality maintenance, (4) water supply, and (5) recreation. The constraint method is used to develop the trade‐offs while a specially modified linear programing and dynamic programing algorithm is used for optimization. Noninferior sets can be obtained with each benefit parameterized singly and in various combinations. Two sets of monthly historical streamflows, one set corresponding to a drought year and the other set to an excess water year, are used to develop the corresponding noninferior sets. These procedures provide guidance for allocating the total benefits derived from a region's water resources and for operating the available system within all statutory, contractual, and other applicable constraints. A very high degree of decomposition of the typically large multiple purpose, multiple facility operation problem is made possible by the above technique, resulting in a rapid delineation of the noninferior policy set. The decision maker participates at various stages of the analysis and can request more or less detail with regard to the noninferior set. In our opinion, information is best presented to him via a series of two dimensional plots representing various cross sections of the noninferior set. Tabular presentations are not conducive to a good appreciation of the consequences of alternative benefit allocation policies.

Optimization of real time operation of a multiple‐reservoir system

This paper addresses a typical requirement of real time multiple‐reservoir operation. A methodology is evolved utilizing a form of dynamic programing (DP) for the selection of an optimal reservoir storage policy path through a specified number of policy periods, and a linear programing (LP) routine is used for period by period optimization. The policy periods, in case of the real time operation, correspond to the number of time periods for which a streamflow prediction model is reasonably reliable. The method results in relatively easy computer implementation and high flexibility in that changes in constraints are simply made and additional reservoirs easily added. The method is of considerable value for the determination of release policies in real time operation of an existing system. As an example, application is made to a real system of reservoirs and hydroelectric facilities associated with the Shasta and Trinity sub‐systems of the California Central Valley Project.

Siltation and Pollution Problems in Spring Creek, Shasta County, Calif.

This article discusses the Trinity River Division of California's Central Valley Project. The diversion of Trinity River water into the Sacramento River Basin was accomplished by the U.S. Bureau of Reclamation by means of several dams and tunnels. The main problems involved were the high erosion‐sedimentation rates in the Spring Creek Basin, which led to a rapid development and growth of the Spring Creek Delta in Keswick Reservoir, and the highly acidic, polluted character of the creek water, which caused serious damage to the fishery in the Sacramento River. Both problems were related to geologic history and mining developments in the basin.

Sedimentation in the Delta‐Mendota Canal

Capacity studies of the U.S. Bureau of Reclamation's Delta‐ Mendota Canal, the largest of the constructed canals of the California Central Valley Project, have revealed several unsuspected issues of large, concrete‐lined canals on flat grades. Some of this new information has already been applied in the design of the huge canal of the San Luis unit of the project, which is now under construction. In addition to proving that design methods must be adjusted for such canals, the studies, which involved dewatering, indicated that sedimentation and biologic growths significantly decrease canal capacity.