A Salton Sea Chronology (Prehistory-2015)

U.S. Bureau of Reclamation (USBR) | January 14th, 2016

A Scientific Assessment of Alternatives for Reducing Water Management Effects on Threatened and Endangered Fishes in California's Bay Delta (2010)

National Academy of Sciences (NAS) | March 19th, 2010

The California Bay-Delta region receives fresh water from the Sacramento and San Joaquin rivers and their tributaries, and some of that water is diverted for agricult

The California Bay-Delta region receives fresh water from the Sacramento and San Joaquin rivers and their tributaries, and some of that water is diverted for agriculture and southern California metropolitan areas. However, the region's growing population and engineered water-control systems have substantially altered the delta ecosystem and have changed the composition of fish species; while some native species have declined, some introduced species have increased. This report provides a scientific evaluation of two "biological opinions" issued by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service in 2008 and 2009, respectively, that require actions to reduce adverse effects of water diversions on delta smelt, Chinook salmon, Central Valley steelhead, and green sturgeon, such as restricting water diversions during certain periods. The report concludes that most of the actions are scientifically justified, but many need clarification concerning details. For example, the Fish and Wildlife Service and the National Marine Fisheries Service actions to reduce risks to delta smelt and juvenile salmon and steelhead by limiting how much water is pumped from the delta in winter have a sound conceptual basis. However, the data do not permit a confident identification of when to limit pumping or the benefits fish receive. Thus careful monitoring, adaptive management, and additional analyses are needed. The report further concludes that our understanding of the risks to the fishes and the benefits likely to accrue from the actions requires an integrated, quantitative analytical framework that ties the various actions together within the species, between smelt and salmonids and sturgeon, and across the watershed. The lack of such an integrated analytic framework hampers both the agencies' and the committee's ability to thoroughly evaluate the effects of the RPAs on the fishes, on water quality and quantity in the delta, and on water operations. Key Messages A proposed U.S. Fish and Wildlife Service action to create or restore 8,000 acres of intertidal and subtidal habitat in the delta is weakly justified, because the relationship between tidal habitats and food availability for smelt is poorly understood. A proposed U.S. Fish and Wildlife Service action to manage the contour line of 2 parts per thousand salinity, called X2, is beneficial to smelt needs further clarification. A proposed U.S. Fish and Wildlife Service action to protect delta smelt by limiting how much water is pumped from the delta to reduce reverse flows in the Old and Middle rivers, two branches of the San Joaquin River is scientifically justified; however, the data do not permit confident identification of when to limit reverse flows or of the benefits fish receive, so careful monitoring, adaptive management, and additional analyses is needed. Adverse effects of all other stressors on the listed fish -- such as contaminants in the delta and structures on rivers that block fishes from access to their spawning habitat -- are potentially large. Regarding a Nation Marine Fisheries Service biological opinion, which applies to the Chinook salmon, steelhead, and green sturgeon in the delta and farther upstream, the committee concluded that on balance the actions are scientifically justified; however, specific environmental triggers, thresholds, and flows should receive additional evaluation that is integrated with the analyses of similar actions for delta smelt. Reversing or even slowing the declines of the listed fish species cannot be accomplished immediately. The effects of an increasing population and the operation of the engineered water-control system have substantially altered the delta ecosystem, including its fish species.

A shift from drought to extreme rainfall drives a stable landslide to catastrophic failure

Nature Portfolio (Springer Nature) | February 7th, 2019

The addition of water on or below the earth’s surface generates changes in stress that can trigger both stable and unstable sliding of landslides and faults.

The addition of water on or below the earth’s surface generates changes in stress that can trigger both stable and unstable sliding of landslides and faults. While these sliding behaviours are well-described by commonly used mechanical models developed from laboratory testing (e.g., critical-state soilmechanics and rate-and-state friction), less is known about the field-scale environmental conditions orkinematic behaviours that occur during the transition from stable to unstable sliding. Here we use radarinterferometry (InSAR) and a simple 1D hydrological model to characterize 8 years of stable sliding of the Mud Creek landslide, California, UsA, prior to its rapid acceleration and catastrophic failure on May 20, 2017. Our results suggest a large increase in pore-fluid pressure occurred during a shift from historic drought to record rainfall that triggered a large increase in velocity and drove slip localization, overcoming the stabilizing mechanisms that had previously inhibited landslide acceleration. Given thepredicted increase in precipitation extremes with a warming climate, we expect it to become more common for landslides to transition from stable to unstable motion, and therefore a better assessmentof this destabilization process is required to prevent loss of life and infrastructure.

A simmering revolt against groundwater cutbacks in California

Stanford University | December 14th, 2022

In 2014, California legislators, focused on groundwater’s accelerating decline during a prolonged drought, passed the Sustainable Groundwater Management Act. Its impera

In 2014, California legislators, focused on groundwater’s accelerating decline during a prolonged drought, passed the Sustainable Groundwater Management Act. Its imperatives: keeping groundwater levels sustainable by 2040 and keeping control of groundwater in local hands. Both goals are now in limbo. As the state endures yet another prolonged drought and state water managers have balked at approving plans covering the basins at greatest risk – the vast majority in the San Joaquin Valley – more growers in a few of the new local groundwater agencies are in revolt at the new rules that will curtail access to the water they once took for granted.

A Simulation-Optimization Model for Water-Resources Management, Santa Barbara, California

U.S. Geological Survey (USGS) | September 1st, 1998

A simulation-optimization model has been developed for the optimal management of the city of Santa Barbara's water resources during a drought. The model, which links grou

A simulation-optimization model has been developed for the optimal management of the city of Santa Barbara's water resources during a drought. The model, which links ground-water simulation with linear programming, has a planning horizon of 5 years. The objective is to minimize the cost of water supply subject to: water demand constraints, hydraulic head constraints to control seawater intrusion, and water capacity constraints. The decision variables are monthly water deliveries from surface water and ground water. The state variables are hydraulic heads. The drought of 1947–51 is the city's worst drought on record, and simulated surface-water supplies for this period were used as a basis for testing optimal management of current water resources under drought conditions. The simulation-optimization model was applied using three reservoir operation rules. In addition, the model's sensitivity to demand, carryover [the storage of water in one year for use in a later year(s)], head constraints, and capacity constraints was tested.

A Spatial Hedonic Analysis of the Housing Market around a Large, Failing Desert Lake: The Case of the Salton Sea in California

Journal of Environmental Planning and Management (Taylor & Francis) | March 2nd, 2018

Many lakes around the world exhibit acute environmental stress due to water transfers, persistent droughts, and polluted runoff. In addition, falling water levels worsen

Many lakes around the world exhibit acute environmental stress due to water transfers, persistent droughts, and polluted runoff. In addition, falling water levels worsen air quality by exposing desiccated shores. To our knowledge, however, no published hedonic study has analyzed the costs of deteriorating water quality jointly with the air quality impacts of falling water levels for a large inland water body. We conduct such an analysis for the Salton Sea, the largest lake in California. Our spatial autoregressive models estimated on single-family properties located within 10 miles (16.1 km) of the Sea show that a 1 km reduction in distance to the Sea results in a $595 decrease in the price of a single-family residence. In addition, a 1% increase in annual particulate matter concentration reduces the value of the average family residence by $1,140. These results highlight the vulnerability of poor rural communities to deteriorating environmental conditions.

A spatially comprehensive, hydrometeorological data set for Mexico, the U.S., and Southern Canada 1950–2013

Nature Portfolio (Springer Nature) | August 18th, 2015

A data set of observed daily precipitation, maximum and minimum temperature, gridded to a 1/16° (~6 km) resolution, is described that spans the entire country

A data set of observed daily precipitation, maximum and minimum temperature, gridded to a 1/16° (~6 km) resolution, is described that spans the entire country of Mexico, the conterminous U.S. (CONUS), and regions of Canada south of 53° N for the period 1950–2013. The dataset improves previous products in spatial extent, orographic precipitation adjustment over Mexico and parts of Canada, and reduction of transboundary discontinuities. The impacts of adjusting gridded precipitation for orographic effects are quantified by scaling precipitation to an elevation-aware 1981–2010 precipitation climatology in Mexico and Canada. Differences are evaluated in terms of total precipitation as well as by hydrologic quantities simulated with a land surface model. Overall, orographic correction impacts total precipitation by up to 50% in mountainous regions outside CONUS. Hydrologic fluxes show sensitivities of similar magnitude, with discharge more sensitive than evapotranspiration and soil moisture. Because of the consistent gridding methodology, the current product reduces transboundary discontinuities as compared with a commonly used reanalysis product, making it suitable for estimating large-scale hydrometeorologic phenomena.

A Spatiotemporal History of Key Pelagic Fish Species in the San Francisco Estuary, CA

Springer | April 11th, 2023

A State Role in Supporting Groundwater Trading with Safeguards for Vulnerable Users: Findings and Next Steps

California Department of Water Resources (DWR) | May 18th, 2022

In those parts of California where groundwater pumping has long exceeded replenishment, people are striving to bring groundwater basins into sustainable conditions within

In those parts of California where groundwater pumping has long exceeded replenishment, people are striving to bring groundwater basins into sustainable conditions within 20 years, between 2040 and 2042, as the Sustainable Groundwater Management Act (SGMA) requires. In some areas, groundwater sustainability agencies (GSAs) – the local agencies tasked with sustainable groundwater management – are beginning to work with other entities and stakeholders to discuss and experiment with the idea of giving groundwater pumpers allocations – allowances to remove a certain amount of water from a groundwater basin – and allowing them to either use their allocation individually or trade allocations between specified parties. Ideally, groundwater trading could ease the economic disruption of cutting back the overall amount of water pumped from a groundwater basin; growers who have less need for pumping could sell their allocation to others willing to pay for it, helping buyers keep their operations functional while compensating sellers. But the concept of groundwater trading raises many questions: How would wetlands, streams, and other ecosystems fed by aquifers be treated in a groundwater trading program? Would operators of farms who lack the resources of larger neighbors be able to benefit from trading? How might trading affect people who depend upon a household well or communities that need reliable groundwater supplies for homes and businesses? How can GSAs work with local stakeholders to develop, implement, and oversee trading programs that help with sustainable groundwater management? There is a State interest behind all of these questions – and a clear need for a focused discussion about groundwater trading.

A Study of Economic and Financial Policies for State Water Projects

State of California | August 5th, 1959