Central Coast

Hydroclimate volatility on a warming Earth

Nature Portfolio (Springer Nature) | January 9th, 2025

Hydrogeologic characterization of the San Antonio Creek Valley watershed, Santa Barbara County, California

U.S. Geological Survey (USGS) | January 31st, 2022

Hydrogeologic Investigation Arroyo Seco Cone

Monterey County Water Resources Agency (MCWRA) | April 15th, 1994

This report presents the findings, analysis, conclusions, and recommendations developed as part of an investigation to characterize the hydrogeology of the Arroyo Seco Co

This report presents the findings, analysis, conclusions, and recommendations developed as part of an investigation to characterize the hydrogeology of the Arroyo Seco Cone area of the Salinas Valley. The purpose of this investigation is to assess the feasibility of developing a seasonal surface water spreading operation utilizing water diverted from the Arroyo Seco in order to enhance ground water recharge in the area. The goal of a project to store water in the ground for subsequent pumping and use is to increase the yield of the Salinas Basin. This investigation defines the hydrogeologic characteristics of the Arroyo Seco Cone area, characterizes the hydrology of the Arroyo Seco and the availability of divertable flows, and estimates the annual recharge that could be achieved through the development of spreading basins.

Hydrogeology and Water Resources of the Los Osos Valley Ground-Water Basin, San Luis Obispo County, California

U.S. Geological Survey (USGS) | July 18th, 1988

The Los Osos Valley ground-water basin is located on the coast of central California. It extends about 3 miles inland and an unknown distance offshore, where it is in h

The Los Osos Valley ground-water basin is located on the coast of central California. It extends about 3 miles inland and an unknown distance offshore, where it is in hydraulic connection with the Pacific Ocean. Its maximum onshore depth is about 1,000 feet. Ground-water flow in the basin was investigated using existing data, geologic mapping, drilling and measurements of potentiometric head, water quality, and streamflow. The basin is underlain largely by relatively impermeable rocks of the Franciscan Complex. Basin fill consists of unconsolidated, complexly layered sediments of Miocene age or younger. Individual beds are generally thin and discontinuous. A three-dimensional digital model of the basin was developed and calibrated to match potentiometric heads and head-dependent flows during water years 1970-77 and 1986. The model simulated poorly the steep vertical potentiometric heads, and it could not simulate perched water tables. In other respects, model results were good and not highly sensitive to likely errors in input data. Infiltrated rainfall contributes about 80 percent of annual recharge to the ground-water basin, and ground-water inflow accounts for almost all the remainder. Net recharge from Los Osos Creek is small. In water year 1986, outflow from the basin consisted of net municipal pumpage (24 percent), net agricultural pumpage (25 percent), net outflow across the ocean boundary (26 percent), perched-water runoff (16 percent), and phreatophyte transpiration (9 percent). During water years 1970-77 net municipal pumpage and net agricultural pumpage accounted for only 10 and 22 percent of total outflow, respectively. The population of Los Osos Valley is expected to increase by about 20,000 people by the year 2010, and municipal water use is expected to increase by about 1,700 acre-feet per year. The model was used to simulate the effects of various future water-supply and wastewater-disposal alternatives on the  ground-water system. Results indicated that if wastewater is centrally treated and recharged to the ground-water basin, the entire projected municipal water demand can be met with locally pumped ground water without inducing seawater intrusion, even during droughts lasting 1 to 3 years. If wastewater is exported from the basin, however, large amounts of seawater intrusion are likely to occur even if nearly half of the municipal water demand is met with imported water.

Hydrogeology and Water Supply of Salinas Valley

Monterey County Water Resources Agency (MCWRA) | June 15th, 1995

The Monterey County Water Resources Agency (MCWRA) convened a panel of 10 geologists, hydrogeologists, and engineers familiar with Salinas Valley ground water basin to at

The Monterey County Water Resources Agency (MCWRA) convened a panel of 10 geologists, hydrogeologists, and engineers familiar with Salinas Valley ground water basin to attempt to reach agreement on the basic physical characteristics of the basin, and the surface and ground water flow within the basin. Agreement on the completeness and accuracy of existing data and previous hydrogeological studies was seen as an important first step in identifying and implementing a technically sound solution acceptable to the public that would stop seawater intrusion that began some 60 years ago. Mike Armstrong, General Manager of MCWRA, instructed the panel to review and, if possible, reach consensus on the hydrogeological characteristics of the basin, define clearly the water resources problems in the basin, and determine surface water and ground water flow within the basin. We were not requested to discuss specific local projects or political and institutional aspects of the problems. The panel met in a closed-door session in Monterey on May 24 and 25, 1995. The session was closed to the public and the press to enable the panelists to discuss and explore ideas and opinions freely without worrying about statements, questions, and hypotheses being repeated out of context. Members of the panel believe the process worked very well. This report presents our findings, conclusions, and recommendations. We were able to achieve more than our original scope of work. There was remarkable unanimity of opinion on our understanding of the physical characteristics of the basin, the hydrologic system, the interaction between surface water and ground water, and definition of the specific ground water problems in the basin. In summary, the facts we agreed upon point so compellingly toward an already identified regional solution to the Valley's ground water resources problems that the panel has included a potential solution. We have included a strong recommendation in this White Paper for implementing that regional solution.

Hydrologic Models and Analysis of Water Availability in Cuyama Valley, California

U.S. Geological Survey (USGS) | May 14th, 2015

Changes in population, agricultural development practices (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demand

Changes in population, agricultural development practices (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demands on available water resources, particularly groundwater, in the Cuyama Valley, one of the most productive agricultural regions in Santa Barbara County. The goal of this study was to produce a model capable of being accurate at scales relevant to water management decisions that could be considered in the evaluation of the sustainable water supply. The Cuyama Valley Hydrologic Model (CUVHM) was designed to simulate the most important natural and human components of the hydrologic system, including components dependent on variations in climate, thereby providing a reliable assessment of groundwater conditions and processes that can inform water users and help to improve planning for future conditions. Model development included a revision of the conceptual model of the flow system, construction of a precipitation-runoff model using the Basin Characterization Model (BCM), and construction of an integrated hydrologic flow model with MODFLOW-One-Water Hydrologic Flow Model (MF-OWHM). The hydrologic models were calibrated to historical conditions of water and land use and, then, used to assess the use and movement of water throughout the Valley. These tools provide a means to understand the evolution of water use in the Valley.

Hydropower capacity factors trending down in the United States

Nature Portfolio (Springer Nature) | June 27th, 2024

Hyper-Salinity Toxicity Thresholds for Nine California Ocean Plan Toxicity Test Protocols

California State Water Resources Control Board (SWRCB) | July 1st, 2012

A growing number of coastal cities in California are exploring the potential for ocean desalination as a means to augment freshwater supplies. There are currently a numbe

A growing number of coastal cities in California are exploring the potential for ocean desalination as a means to augment freshwater supplies. There are currently a number of desalination facilities proposed or operating in California. The process of desalination most commonly utilizes reverse osmosis (RO) to remove salts from groundwater, reclaimed water, and seawater. This process results in production of hypersaline reject brine. This reject brine may be discharged into the marine environment, sometimes in combination with discharge from a sewage treatment plant or power plant effluent. Typical RO reject brine produced using 100% seawater can have approximately twice the original salt content of seawater. In order to ensure that brine discharges do not pose risk to coastal receiving waters, it is anticipated that desalination plants will be required to monitor effluent toxicity. Monitoring requirements will likely include testing for effluent toxicity using some combination of the short-term chronic toxicity test protocols listed in the 2009 California Ocean Plan (SWRCB, 2009). While the tests listed in the Ocean Plan have been the subject of ongoing research, no comprehensive studies of the effects of hyper-salinity have been conducted with all seven toxicity test organisms (nine protocols when including sand dollar and urchin fertilization endpoints). The results from these tests will allow determination of the toxicity of hypersaline brine in the absence of any additional toxic constituents that may be produced during the desalination process. These results provide resource managers with background information to facilitate interpretation of toxicity test results from desalination plant effluent testing and permitting of desalination facilities. The results will also be used in the development of an amendment to the California Ocean Plan that addresses impacts to marine life from intakes and discharges from desalination facilities.

Identifying the Amount of Wastewater that is Available and Feasible to Recycle in California

Water Research Foundation (WRF) | July 24th, 2023

Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming

Wiley | February 21st, 2013

Ocean acidification represents a threat to marine species worldwide, and forecasting the ecological impacts of acidification is a high priority for science, management, a

Ocean acidification represents a threat to marine species worldwide, and forecasting the ecological impacts of acidification is a high priority for science, management, and policy. As research on the topic expands at an exponential rate, a comprehensive understanding of the variability in organisms' responses and corresponding levels of certainty is necessary to forecast the ecological effects. Here, we perform the most comprehensive meta‐analysis to date by synthesizing the results of 228 studies examining biological responses to ocean acidification. The results reveal decreased survival, calcification, growth, development and abundance in response to acidification when the broad range of marine organisms is pooled together. However, the magnitude of these responses varies among taxonomic groups, suggesting there is some predictable trait‐based variation in sensitivity, despite the investigation of approximately 100 new species in recent research. The results also reveal an enhanced sensitivity of mollusk larvae, but suggest that an enhanced sensitivity of early life history stages is not universal across all taxonomic groups. In addition, the variability in species' responses is enhanced when they are exposed to acidification in multi‐species assemblages, suggesting that it is important to consider indirect effects and exercise caution when forecasting abundance patterns from single‐species laboratory experiments. Furthermore, the results suggest that other factors, such as nutritional status or source population, could cause substantial variation in organisms' responses. Last, the results highlight a trend towards enhanced sensitivity to acidification when taxa are concurrently exposed to elevated seawater temperature.