Sacramento River

Urban and Agricultural Water Use in California, 1960–2015

Pacific Institute | June 22nd, 2020

Water is the lifeblood of California. It provides for the household needs of 40 million people. It generates electricity and cools power plants. It supports one of the mo

Water is the lifeblood of California. It provides for the household needs of 40 million people. It generates electricity and cools power plants. It supports one of the most productive agricultural regions in the world and various commercial and industrial activities, ultimately fueling the fifth largest economy in the world. Water is also critical to the health and viability of the state’s diverse aquatic and terrestrial ecosystems. This paper examines statewide urban and agricultural water-use trends from 1960 to 2015 using data from the California Department of Water Resources (DWR). We find that California has experienced a dramatic decoupling between water use and growth. Since 1967, California’s population has doubled, and its economic output has increased by a factor of five. Yet statewide water use increased by only 20 percent over this period due to improvements in urban and agricultural efficiency, as well as a shift to higher-value crops and less water-intensive commercial and industrial activities.  Despite positive signs, water use in California remains high. Across the state, rivers and streams are under stress from overuse, and groundwater is over-tapped. Climate change and continued growth are increasing pressure on the state’s water resources, including on water supply, demand, and quality. To address these challenges, we must continue and even expand efforts to improve the water-use efficiency of our homes, businesses, industries, and farms. Moreover, we urge the state to improve data collection and online systems to make data more easily, quickly, and readily available.

Urban Levee Design Criteria

California Department of Water Resources (DWR) | May 15th, 2012

The Urban Levee Design Criteria (ULDC) provides engineering criteria and guidance for the design, evaluation, operation, and maintenance of levees and floodwalls that pro

The Urban Levee Design Criteria (ULDC) provides engineering criteria and guidance for the design, evaluation, operation, and maintenance of levees and floodwalls that provide an urban level of flood protection (i.e., 200-year level of flood protection) in California, as well as for determining design water surface elevations (DWSE) along leveed and unleveed streams. Other topics beyond design and evaluation are presented to provide reasonable assurance that once a levee or floodwall is found to provide an urban level of flood protection, it will continue to do so. RELATED CONTENT: Urban Level of Flood Protection Criteria

Urban Level of Flood Protection Criteria

California Department of Water Resources (DWR) | November 12th, 2013

The Urban Level of Flood Protection Criteria was developed in response to requirements from the Central Valley Flood Protection Act of 2008, enacted by Senate Bill (SB) 5

The Urban Level of Flood Protection Criteria was developed in response to requirements from the Central Valley Flood Protection Act of 2008, enacted by Senate Bill (SB) 5 (2007), to strengthen the link between flood management and land use. The California Department of Water Resources (DWR) developed these criteria as a systematic approach to assist affected cities and counties within the Sacramento-San Joaquin Valley in making findings related to an urban level of flood protection before approving certain land-use decisions. In preparing these criteria, DWR used its broad experience and expertise in flood management and planning to address concerns related to flood protection and flood risk management. RELATED CONTENT: Urban Levee Design Criteria

Urban Water Conservation in the Sacramento, California Region During the 2014-2016 Drought

ProQuest Dissertations Publishing | December 30th, 2019

Urban Water Revolution: Sustainable Water Futures for California Cities

American Society of Civil Engineers (ASCE) | July 15th, 2020

California has consistently altered natural water resources to provide water for its growing population and to support the fifth largest economy in the world. However, th

California has consistently altered natural water resources to provide water for its growing population and to support the fifth largest economy in the world. However, the old ways of coping with the California’s urban water needs—overdraft of groundwater, stream depletion, and greater imports—will no longer meet the demands of the 21st century. We examine California’s water history and present several promising solutions to the challenge of urban water security: a combination of conservation and efficiency, desalination, stormwater capture, water re-use, and water banking. These options for urban water, including direct potable reuse, will help dry cities in California and elsewhere achieve more sustainable and diversified water supply portfolios. Pilot and demonstration-scale projects, along with innovations in systems management and new regulations, point the way toward more resilient water supplies for dry cities. Movement toward regional collaboration, implementation of new technologies, and new regulatory regimes are helping to realize a one-water vision. Different cities will develop their own water supply portfolio options appropriate for their geography, values, and urban form on a path toward meeting the urban water challenges of this century.

Use of the SmeltCam as an Efficient Fish-Sampling Alternative Within the San Francisco Estuary

University of California, Davis (UC Davis) | June 1st, 2021

Resource managers often rely on long-term monitoring surveys to detect trends in biological data. However, no survey gear is 100% efficient, and many sources of bias can

Resource managers often rely on long-term monitoring surveys to detect trends in biological data. However, no survey gear is 100% efficient, and many sources of bias can be responsible for detecting or not detecting biological trends. The SmeltCam is an imaging apparatus developed as a potential sampling alternative to long-term trawling gear surveys within the San Francisco Estuary, California, to reduce handling stress on sensitive species like the Delta Smelt (Hypomesus transpacificus). Although believed to be a reliable alternative to closed cod-end trawling surveys, no formal test of sampling efficiency has been implemented using the SmeltCam. We used a paired deployment of the SmeltCam and a conventional closed cod-end trawl within the Napa River and San Pablo Bay, a Bayesian binomial N-mixture model, and data simulations to determine the sampling efficiency of both deployed gear types to capture a Delta Smelt surrogate (Northern Anchovy, Engraulis mordax) and to test potential bias in our modeling framework. We found that retention efficiency—a component of detection efficiency that estimates the probability a fish is retained by the gear, conditional on gear contact—was slightly higher using the SmeltCam (mean = 0.58) than the conventional trawl (mean = 0.47, Probability SmeltCam retention efficiency > trawl retention efficiency = 94%). We also found turbidity did not affect the SmeltCam’s retention efficiency, although total fish density during an individual tow improved the trawl’s retention efficiency. Simulations also showed the binomial model was accurate when model assumptions were met. Collectively, our results suggest the SmeltCam to be a reliable alternative to sampling with conventional trawling gear, but future tests are needed to confirm whether the SmeltCam is as reliable when applied to taxa other than Northern Anchovy over a greater range of conditions.

User Manual for the California Central Valley Groundwater-Surface Water Simulation Model

California Department of Water Resources (DWR) | June 13th, 2013

This report describes the input and output files for the California Central Valley Groundwater-Surface Water Simulation Model (C2VSim). C2VSim is an integrated numeri

This report describes the input and output files for the California Central Valley Groundwater-Surface Water Simulation Model (C2VSim). C2VSim is an integrated numerical model simulating land surface processes and groundwater and surface water flows in the main alluvial aquifer system of California’s Central Valley (figure 1). C2VSim was developed using the Integrated Water Flow Model (IWFM) application, which couples a three-dimensional finite element groundwater simulation process with one-dimensional land surface, stream flow, lake, unsaturated zone and smallstream watershed simulation processes. The C2VSim version described in this report runs under IWFM version 3.02 and utilizes a coarse grid, and is thus referred to as version 3.02-CG. In addition, the input files for the C2VSim model are regularly updated to correct errors, incorporate improved input data or extend the simulation time period. These updates are referred to as revisions; this report describes the data in revision R374, released in June 2013. The C2VSim model inputs include monthly historical precipitation, stream inflows, surface water diversions, land use and crop acreages for the simulation period, October 1921 through September 2009. C2VSim dynamically calculates crop water demands, allocates contributions from precipitation, soil moisture and surface water diversions, and calculates the groundwater pumpage required to meet the remaining demand. The coarse grid version of the C2VSim model incorporates a finite element grid with 1392 elements, grouped into 21 water budget subregions (figure 1), which are further grouped by drainage basin into five hydrologic regions. The model subregions are based on Depletion Study Areas (DSAs), originally created by the DWR Division of Planning for estimating regional water supplies and demands. Hydrologic parameters (including hydraulic conductivities, storage parameters and recession coefficients) were calibrated to match observed values including groundwater heads, groundwater head differences between well pairs, surface water flows, and stream-groundwater flows for the period between September 1975 and October 2003. The model simulates the historical response of the Central Valley’s groundwater flow system to historical stresses, and can also be used to simulate the response to projected future stresses. Agricultural groundwater pumping is not monitored in the Central Valley, and the C2VSim model provides pumpage estimates that are considered robust because they are constrained spatially and temporally by the estimated demand and surface water supplies. The calibrated model is also being used as the basis for the groundwater flow component of CalSim 3, a water resources planning model for simulating operation of the California State Water Project (SWP) and Federal Central Valley Project (CVP).

Using Conceptual Models and Decision-Support Tools to Guide Ecosystem Restoration Planning and Adaptive Management: An Example from the Sacramento–San Joaquin Delta, California

University of California, Davis (UC Davis) | October 1st, 2012

The Sacramento–San Joaquin Delta (the Delta) is located on the western edge of California’s Central Valley and is of critical ecological and economic importance. H

The Sacramento–San Joaquin Delta (the Delta) is located on the western edge of California’s Central Valley and is of critical ecological and economic importance. However, ecosystem alterations for human uses changed many of the Delta’s natural processes, and it is now considered in need of restoration. An approach was developed to evaluate and rank restoration actions in the Delta under the Ecosystem Restoration Program’s Delta Regional Ecosystem Restoration Implementation Plan (DRERIP). The DRERIP approach provides an explicit framework for evaluating restoration actions, using linked conceptual models, an action evaluation procedure, and a decision-support tool. Conceptual models allow scientists and managers to synthesize scientific information and make qualitative predictions about ecosystem function and restoration outcomes to guide and focus restoration efforts. The action evaluation procedure is a structured assessment of restoration actions. The procedure clearly describes actions to be evaluated, assesses the magnitude (importance and scale) and certainty of anticipated ecological outcomes, estimates degrees of worth (achieving intended outcomes) and risk (causing adverse consequences), evaluates the reversibility of the action, and identifies opportunities for learning. The values for worthiness, risk, reversibility, and learning opportunity are used in the decision- support tool to determine the fate of a proposed action. The decision-support tool is a structured decision tree that determines the disposition of an action: whether a restoration project should be discarded, revised with a different approach and re-evaluated, or implemented; and, if implemented, at what scale (targeted research, pilot project, or full implementation). The DRERIP approach provides managers with a valuable tool for restoration planning, and a foundation for integration with quantitative methods for a comprehensive ecosystem restoration plan.

Using Landsat and MODIS satellite collections to examine extent, timing, and potential impacts of surface water inundation in California croplands

Remote Sensing Applications: Society and Environment (RSASE) | October 1st, 2022

The state of California, United States of America produces many crop products that are both utilized domestically and exported throughout the world. With nearly 39,000 km

The state of California, United States of America produces many crop products that are both utilized domestically and exported throughout the world. With nearly 39,000 km2 of croplands, monitoring unintentional and intentional surface water inundation is important for water resource management and flood hazard readiness. We examine inundation dynamics in California croplands from 2003 to 2020 by intersecting monthly surface water maps (n = 216 months) derived using two satellite remote sensing platforms (Landsat and Moderate Resolution Imaging Spectroradiometer [MODIS]) with a high-quality cropland map generated by the California Department of Water Resources. Surface water maps were produced using the Dynamic Surface Water Extent model, in which satellite image pixels are classified into different levels of detection confidence. Our analysis focused on calculating monthly and annual occurrence of “high confidence” water for each satellite collection across eight cropland types and 58 counties. Results indicate that 49.9% (MODIS) to 56.4% (Landsat) of croplands were inundated at least once during the 18-year timespan. Rice crops, due to their unique need of consistent surface water and dominance as a crop type in CA, had the highest proportion of and mean annual inundation area, while citrus crops had the lowest. Mean monthly inundation patterns in most croplands followed California's precipitation patterns with high inundation during the winter and spring rainy season. At the county level, croplands in the southern Central Valley typically had high occurrences of inundation in conjunction with large crop areas. Exposure and sensitivity of inundation for three crop types (citrus, deciduous, and vineyards) that are typically less associated with intentional inundation were geographically variable, but overall were generally highest in counties in the southern Central Valley, California's primary agricultural region. Flood and precipitation related crop insurance claims indicated that rice had the highest mean indemnity payout for any month with damages typically occurring in March and April. Insurance claims were also high in deciduous fruit and nut crops, which had peak damages in February. A comparison between inundation results and insurance claims suggests that the inundation mapped by our process coincides with claim activity. These data elucidate water inundation patterns across the state that can serve to inform farmers, insurers, decision makers, resource managers, and flood mitigation professionals.

Using the Distinct Population Segment concept to protect fishes with low levels of genomic differentiation: conservation of an endemic minnow (Hitch, Lavinia exilicauda)

American Fisheries Society (AFS) | December 23rd, 2018

In the United States, the Endangered Species Act (ESA) of 1973 was enacted to conserve species that are endangered or threatened throughout all or a portion of their rang

In the United States, the Endangered Species Act (ESA) of 1973 was enacted to conserve species that are endangered or threatened throughout all or a portion of their range. The definition of “species” includes subspecies and distinct population segments (DPSs). Among freshwater fishes, the use of DPS designations has largely been restricted to salmonids, although the DPS concept is increasingly applied to other fishes as well. As more taxa approach threatened status, the difficult question becomes what to do when genetic evidence does not strongly support formal taxonomic designations (full species or subspecies). We examine the potential application of the DPS concept to protect fishes by using the example of the Hitch Lavinia exilicauda, a cyprinid fish that is endemic to California. The Hitch is divided into three formally described, geographically separate subspecies (the Sacramento, Monterey, and Clear Lake Hitches). However, genomic studies (i.e., restriction site‐associated DNA sequencing), presented here with three independent analyses using a large data set, only weakly supported subspecies designations. Results suggested population structure but not subspecies structure. Nevertheless, conventional taxonomic methods, strong contemporary isolation, the importance of protecting genetic diversity, and high cultural value still qualify all three designated subspecies for DPS status and demonstrate how taxa such as the Clear Lake Hitch can warrant protection under the ESA.