The Basin Characterization Model—A Regional Water Balance Software Package

U.S. Geological Survey (USGS) | March 22nd, 2021

This report documents the computer software package, Basin Characterization Model, version 8 (BCMv8)—a monthly, gridded, regional water-balance model—and provides det

This report documents the computer software package, Basin Characterization Model, version 8 (BCMv8)—a monthly, gridded, regional water-balance model—and provides detailed operational instructions and example applications. After several years of many applications and uses of a previous version, CA-BCM, published in 2014, the BCMv8 was refined to improve the accuracy of the water-balance components, particularly the recharge estimate, which is the most difficult to accurately assess. The improvement of the various water-balance components targeted the actual evapotranspiration component, which, in turn, reduced the uncertainty of the recharge estimate. The improvement of this component was enabled by the availability of a national, gridded actual-evapotranspiration product from the U.S. Geological Survey that was unique in its scope to combine remotely sensed spatial variability and ground-based long-term water-balance constraints. This dataset provided the ability to assess monthly actual evapotranspiration for 62 vegetation types and to perform regional calibration in watersheds throughout California with the objective of closing the water balance using improved estimates for each component. The refinements, including vegetation-specific evapotranspiration, enabled the development of applications that could explore various aspects of landscape disturbance, such as wildfire, forest management, or urbanization. The improvements to BCMv8 also provided the ability to assess long-term sustainability of water resources under a variety of management applications or future climate projections.

The Bay Delta Conveyance Facility: Affordability and Financing Considerations

California Debt and Investment Advisory Commission (CDIAC) | November 1st, 2014

The Bay Delta Conservation Plan (BDCP) is a collaborative effort involving numerous state and federal agencies with the goal of restoring and protecting the environmental

The Bay Delta Conservation Plan (BDCP) is a collaborative effort involving numerous state and federal agencies with the goal of restoring and protecting the environmental health of the Sacramento-San Joaquin Delta while also improving the reliability of an important source of California’s water supply. Currently, the Delta provides vital water supplies to municipal, industrial and agricultural water users in the Central Valley and coastal and Southern California. These water deliveries are crucial to the state’s economy and represent a critical source of water for more than 25 million California residents. According to the BDCP documents, in the absence of the various conservation measures proposed in the plan, Delta water supplies are expected to become increasingly unreliable, water quality in the Delta would be vulnerable due to sea level rise and associated saltwater intrusion, and the state would be exposed to potentially severe public health consequences resulting from a major seismic event that could damage Delta facilities and temporarily halt water exports. This report provides a preliminary assessment of the affordability and financing considerations of the Delta conveyance facility. The report does not address the merits of the BDCP per se or the question of whether the state and other parties involved in the project should proceed with this project.

The Benefits of Headwater Forest Management

Public Policy Institute of California (PPIC) | April 1st, 2020

Forests in California are increasingly vulnerable to major wildfires and droughts that threaten the benefits they provide. Improving the health of headwater forests in th

Forests in California are increasingly vulnerable to major wildfires and droughts that threaten the benefits they provide. Improving the health of headwater forests in the Sierra, in particular—where most of the state’s surface water supplies originate—will provide an array of social, economic, and environmental benefits across multiple sectors and geographies. Research by forest ecologists and wildfire behavior experts finds that the best way to realize these benefits is to reestablish and maintain lower densities of trees, which will help make these forests more resilient to fire, drought, and pests.  Healthier forests can support rural communities, reduce air quality impacts from wildfires, securely store carbon and reduce greenhouse gas emissions, protect water quality from post-fire erosion, and increase water supply. The broad base of beneficiaries of headwater forest management includes rural communities in the headwater region, regions that are vulnerable to smoke impacts from major wildfires, and major urban areas and agricultural regions that receive water and hydropower from headwater forests.  Improving forest health will require a substantial lift from an array of private and public entities—along with new policies and sources of funding to facilitate complex, collaborative management. Clarifying the benefits and beneficiaries of forest management is a critical step in motivating long-term stewardship, and will inform efforts to craft financial tools, policies, and other governance solutions needed to make this heavy lift. By assessing what is known about the benefits of forest management, this report provides crucial information for ongoing policy discussions on long-term stewardship of California’s headwater forests. 

The Big Water Supply Shift: Groundwater Key to Water Security in California's Changing Climate

Union of Concerned Scientists | November 1st, 2015

For more than a century, California has relied on its snowmelt-fed reservoirs, rivers, and streams for the majority of its water, but drought and climate chang

For more than a century, California has relied on its snowmelt-fed reservoirs, rivers, and streams for the majority of its water, but drought and climate change are depleting those traditional supplies. Snow is already melting as many as 30 days earlier than in the mid-twentieth century, meaning less water is available during the hotter months when water demand is highest. California is increasingly turning to groundwater to meet its water needs. Today, groundwater supplies up to 50 percent of California’s water, but California’s prolonged drought has led to the over-pumping of groundwater, overdrafting the Central Valley’s aquifers. Sustainable groundwater management will allow the state to adapt to climate change while increasing water reliability in the future.

The Burns-Porter Act: A California High Water Mark

State Water Contractors (SWC) | April 2nd, 1984

The California drought: A quasi-experimental analysis of social policy

Journal of Applied Behavior Analysis (Wiley) | January 15th, 1980

The California Peripheral Canal: Who Backed It, Who Fought It

California Agriculture (UCANR) | January 3rd, 1983

The California Storm of January 1862

Quaternary Research (Elsevier) | September 2nd, 1996

The greatest storm in the written history of California struck the region in the winter of 1861–1862. The unusual weather began on Christmas Eve, 1861, and persisted fo

The greatest storm in the written history of California struck the region in the winter of 1861–1862. The unusual weather began on Christmas Eve, 1861, and persisted for some 45 days as a series of middle-latitude cyclones made landfall along the California coast. Episodes of very cold and very warm temperatures occurred both during the storm and in the spring of 1862 as meridional flow prevailed. Heavy precipitation swelled the Santa Ana River to more than triple the highest estimated discharge in this century. High water levels in coastal streams between Los Angeles and San Diego persisted into the spring. Lakes were created in the Los Angeles Basin and the Mojave Desert. Arroyos were cut. Sediments from the flood may be preserved in offshore basins.

The California Stream Condition Index

California State Water Resources Control Board (SWRCB) | December 1st, 2015

The California Stream Conditon Index (CSCI) is a biological scoring tool that helps aquatc resource managers translate complex data about benthic macroinver

The California Stream Conditon Index (CSCI) is a biological scoring tool that helps aquatc resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score indicates whether, and to what degree, the ecology of a stream is altered from a healthy state. Direct measures of ecosystem health like the CSCI are preferable to those based on chemical or physical measurements for many management questons. Living organisms integrate the efects of multple stressors, such as sedimentaton, nutrient enrichment and riparian disturbance, over both space and tme.

The California Stream Condition Index (CSCI): A New Statewide Biological Scoring Tool for Assessing the Health of Freshwater Streams

California State Water Resources Control Board (SWRCB) | September 1st, 2015

California’s dramatic environmental diversity supports a broad array of natural stream types throughout the state. Bioassessment of freshwater stream and rivers is esp

California’s dramatic environmental diversity supports a broad array of natural stream types throughout the state. Bioassessment of freshwater stream and rivers is especially challenging in such a region because the reference condition, or the benchmark of biological condition expected when human disturbance in the environment is absent or minimal, varies greatly among natural stream types. Previous indices used by monitoring programs were developed on a regional basis to help partition the state’s environmental diversity, but statewide assessments were confounded by different criteria used in different regions. The CSCI, which translates complex data about individual benthic macroinvertebrates (BMIs) found living in a stream into an overall measure of stream health, was developed specifically to address some of the shortcomings of earlier indices. First, the CSCI was developed with a much larger, more representative data set that makes it applicable statewide and that covers the broad range of environmental variability among natural stream types. Second, the CSCI sets biological benchmarks for a site based on its site-specific environmental setting. Finally, the CSC combines two separate types of indices, each of which provides unique information about the biological condition of a stream: a multi-metric index (MMI) that measures ecological structure and function, and an observed-to-expected (O/E) index that measures taxonomic completeness. Together they provide multiple lines of evidence about the condition of a stream, providing greater confidence in results than a single index.