Central Coast

Beneath the Surface: Why Reservoirs Won't Solve California's Water Woes

Center for Biological Diversity (CBD) | November 19th, 2024

Water storage and conveyance have fundamentally shaped modern California. The vast agricultural industry, as well as globally important cities like Los Angeles, were made

Water storage and conveyance have fundamentally shaped modern California. The vast agricultural industry, as well as globally important cities like Los Angeles, were made possible by storing and moving water around the state. Reservoirs are one of the primary components of California’s water storage system. There are nearly 1,500 surface storage reservoirs throughout the state, which together can store a year’s supply of water for farms and cities. But reservoirs come with high costs. They destroy and degrade habitats and alter flows in rivers and streams, harming native fish and wildlife. They emit significant amounts of greenhouse gases, worsening climate change. They cost taxpayers billions of dollars to build and maintain. And as the climate continues to warm, reservoirs will become less efficient, losing more and more of the water they hold to evaporation.  This report examines reservoirs’ environmental harms and explains why new reservoirs are not the solution to our 21st century water problems. 

Benefit Accounting of Nature-Based Solutions for Watersheds Landscape Assessment

United Nations (UN) | August 3rd, 2020

This landscape assessment is the outcome of Phase 1 of a tri-phased project and was designed to inform the path forward for engaging the private sector to invest in natu

This landscape assessment is the outcome of Phase 1 of a tri-phased project and was designed to inform the path forward for engaging the private sector to invest in nature-based solutions (NBS). A literature review was undertaken to understand the contemporary thinking around NBS and identify key opportunities and challenges faced by decision makers, practitioners and researchers. Interviews conducted with representatives of businesses, civil society and academia who have already implemented NBS projects or are looking to do so yielded qualitative responses to complement or contrast with the findings from the literature review.

Benefit-Cost Analysis of the Delta Conveyance Project

Berkeley Research Group (BRG) | May 16th, 2024

This report presents the results of a benefit-cost analysis for the Delta Conveyance Project (DCP), a plan to modernize the State Water Project (SWP)’s conveyance infra

This report presents the results of a benefit-cost analysis for the Delta Conveyance Project (DCP), a plan to modernize the State Water Project (SWP)’s conveyance infrastructure in the Sacramento-San Joaquin River Delta (Delta). The SWP plays a crucial role in supplying water resources to 27 million Californians. Businesses in the area served by the SWP produce $2.3 trillion in goods and services annually, making it the world’s eighth-largest economy. The SWP delivers an average of 2.56 million acre-feet of water annually to urban and agricultural customers in the Bay Area, Central Valley, Central Coast, and Southern California. However, by 2070, climate change and sea-level rise are expected to reduce SWP deliveries by approximately 22%, or 546 thousand acre-feet per year (TAF/yr). In addition, the SWP faces an ongoing risk of service disruptions following seismic events near the Delta; these events could cause outages and reduce the quality of water exports from the SWP south of the Delta.

Benthic Invertebrate and Deposited Sediment TMDL Guidance for the Pajaro River Watershed

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

The Pajaro River and its tributaries are exposed to sediments from a variety of sources. To establish limits for regulating this pollutant, it is necessary to u

The Pajaro River and its tributaries are exposed to sediments from a variety of sources. To establish limits for regulating this pollutant, it is necessary to understand how and where deposition of sediments impact biological health. Benthic, or bottom-dwelling, invertebrates offer a direct way to assess the impacts of deposited sediment on the integrity of stream ecosystems. The channel bed is where sediments accumulate and persist, so benthic macroinvertebrates that live in this ha bitat provide a responsive indicator of the effect of these sediments. Previous criteria for bedded sediment fines in spawning gravels have been established for salmonids, but these may not be appropriate to all stream segments, are not typically measured in stream assessments, and are confounded by other factors limiting steelhead vitality. Instead, the effects of sediment cover can be evaluated using benthic macroinvertebrates (BMIs) as indicators of stream condition to assess any stream segment and can be related to the bioassessment and stream habitat surveys of the Surface Water Ambient Monitoring Program (SWAMP) . The approach taken in this study was to select 25 sites throughout the perennial Pajaro watershed and in the adjacent upper Coyote Creek watershed that represented a cross-section of land uses, above and below reservoirs (unregulated/regulated flows), and in varied geographic settings that would permit examining source area influences on sediment deposition. Rather than define conventional TMDL estimates for daily loads of sediment, a more relevant survey of the cover of deposited fine and sand (FS) sediments on the stream bed was used here to find the level at which BMIs lost integrity of species c omposition and diversity. BMI responses we re-examined at the reach scale (50-meter channel length ) and at local patch scales (30x3 0 cm) of varied FS sedim ent cover . The data were used to define target levels at which sediment impairs stream bed habitat quality. Reaches of varied sediment cover were compared to conditions at relatively undisturbed reference streams of the Central Coast region to evaluate sediment impacts. Significant loss of species diversity and altered community type occurred above a sediment cover range of 40% FS at both reach and local-patch scales. In a range of 20-40% FS , BMI diversity declined, showing incipient losses of biological integrity . Richness of mayfly, stonefly and caddisfly taxa richness (EPT) was used as an indicator of biological effects of sediment, and reduced diversity associated with sediment increase corresponded to declines below the criterion 10th percentile of reference site EPT found in other central coast streams . Because of multiple stressors, some streams may not achieve these sediment or EPT targets just by improving the local sediment condition . For example, streams that are regulated (below reservoirs) or in arid regions may be influenced by temperature, dissolved minerals and/or elevated pH , in addition to sediment . Rankings of streams surveyed were based either on sediment cover within the wetted stream width or the entire bankfull channel profile, accounting for both current habitat conditions and recent environmental exposure . Although the design of this study examined sediment deposition at different spatial scales and used a variety of sediment measures, the results are compatible with habitat and bioassessment surveys using standard SWAMP protocols. Only three to five of the 25 streams surveyed in the Pajaro region showed sediment and diversity levels indicating likely sediment deposition impacts. Results from this study can be used to identify streams where sediment degradation to biological integrity is likely (at >40% FS) , and those in a warning range (20-40% FS) that should be flagged for further assessment.

Best Management Practices of the Sustainable Management of Groundwater: Land Subsidence (Draft)

California Department of Water Resources (DWR) | July 23rd, 2025

For almost a century, parts of California have been gradually sinking, impacting critical infrastructure and the communities who rely on it. Recognizing this challenge, t

For almost a century, parts of California have been gradually sinking, impacting critical infrastructure and the communities who rely on it. Recognizing this challenge, the Department of Water Resources has released a draft Best Management Practices document for public comment that will help local water agencies address this growing concern and support groundwater reliant communities. Click here for the full DWR press release.

Biennial Report of the Fish and Game Commission of California 1924-26

California Fish and Game Commission | June 30th, 1926

Biological sensitivities to high-resolution climate change projections in the California current marine ecosystem

Wiley | July 28th, 2022

Brief communication: Meteorological and climatological conditions associated with the 9 January 2018 post-fire debris flows in Montecito and Carpinteria, California, USA

Natural Hazards and Earth System Sciences, European Geosciences Union | November 19th, 2018

The Thomas Fire burned 114,078 ha in Santa Barbara and Ventura counties, southern California, during December 2017–January 2018. On 9 January 2018, high-intensity rai

The Thomas Fire burned 114,078 ha in Santa Barbara and Ventura counties, southern California, during December 2017–January 2018. On 9 January 2018, high-intensity rainfall occurred over the Thomas Fire burn area in the mountains above the communities of Montecito and Carpinteria, initiating multiple devastating debris flows. The highest rainfall intensities occurred with the passage of a narrow rainband along a cold front oriented north to south. Orographic enhancement associated with moist southerly flow immediately ahead of the cold front also played a role. We provide an explanation of the meteorological characteristics of the event and place it in historic context.

Building water resilience in the face of cascading wildfire risks

American Association for the Advancement of Science (AAAS) | September 15th, 2023

Bulletin 118 - California's Groundwater Update 2013

California Department of Water Resources (DWR) | April 15th, 2015

California’s Groundwater Update 2013 compiles and analyzes readily available groundwater information to characterize California’s groundwater basins, aquifers, and we

California’s Groundwater Update 2013 compiles and analyzes readily available groundwater information to characterize California’s groundwater basins, aquifers, and well infrastructure. It also presents data and analysis related to groundwater monitoring efforts, aquifer conditions in response to extraction, groundwater management practices, and conjunctive management programs. It expands and enhances baseline groundwater information on a regional scale, identifies challenges associated with sustainable groundwater management, and helps guide implementation of diverse resource management strategies. The set of data, information, and analysis developed can help local and regional groundwater managers, as well as individual well owners, better understand California’s hidden and commonly misunderstood resource. This Bulletin has been uploaded in the following separate files reflecting hydrologic regions and appendices. Chapter One / Introduction  Chapter Two / State-wide Update  Chapter Three / North Coast Chapter Four / San Francisco Bay Chapter Five / Central Coast Chapter Six / South Coast  Chapter Seven / Sacramento River Chapter Eight / San Joaquin River Chapter Nine / Tulare Lake Chapter Ten / North Lahontan Chapter Eleven / South Lahontan Chapter Twelve / Colorado River Appendix A: Methods and Assumptions Appendix B: CASGEM Basin Prioritization Appendix C: Groundwater Use Data 2010-2015 Appendix D: Conjunctive Management Survey Appendix E: Change in Groundwater in Storage Appendix F: Subsidence