High Resolution Measurement of Levee Subsidence Related to Energy Infrastructure in the Sacramento-San Joaquin Delta

California Energy Commission (CEC) | August 31st, 2018

We assess flood overtopping potential (when flood water elevation exceeds levee elevation) to the levees surrounding the islands in the interior of California's S

We assess flood overtopping potential (when flood water elevation exceeds levee elevation) to the levees surrounding the islands in the interior of California's Sacramento-San Joaquin Delta. Because critical natural gas infrastructure is susceptible to overtopping-related disruption, we focus our analysis on regions that are crossed by the network of the state's natural gas pipelines. We use laser scanning data collected during 2015-2016 to estimate subsidence rates since 2007 when an earlier, Delta-wide, airborne laser-scanning topographic dataset was collected. For each levee studied, we combine: (1) the estimated subsidence rate, (2) a conservative range of sea-level rise projections and, (3) an estimate of the 100-year freshwater flood stage to project the time until exceedance of the federal levee height standard (PL84-99). We find that subsidence rates vary from 0-5 centimeters per year (cm/yr) with mean values of ~1-2 cm/year. Local gradients in subsidence can be on the order of cms/yr over a distance of 10s of meters parallel to the levee crests, and these types of gradients are present near some pipeline crossings. The Sherman Island region has subsidence rates close to a factor of 2 greater than other areas considered. Our projections indicate general ranges of exceedance date from about 2060 (fast sea-level rise scenario) to 2080 (slow sea-level rise scenario) with some places projected to exceed threshold by about 2050.

High-elevation snowpack loss during the 2021 Pacific Northwest heat dome amplified by successive spring heatwaves

Nature Portfolio (Springer Nature) | December 13th, 2023

High-resolution mapping of global surface water and its long-term changes

Nature Portfolio (Springer Nature) | December 7th, 2016

The location and persistence of surface water (inland and coastal) is both affected by climate and human activity and affects climate, biological diversity and hu

The location and persistence of surface water (inland and coastal) is both affected by climate and human activity and affects climate, biological diversity and human wellbeing. Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions, statistical extrapolation of regional data and satellite imagery, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal. Losses in Australia17 and the USA18 linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water-management decision-making.

High-Salinity Sensitivity Study: Short-and Long-Term Exposure Assessments

California State Water Resources Control Board (SWRCB) | April 12th, 2013

The West Basin Municipal Water District (WBMWD) High Salinity Sensitivity Study (HSS Study) comprehensively evaluated the potential short-term and long-term exposure effe

The West Basin Municipal Water District (WBMWD) High Salinity Sensitivity Study (HSS Study) comprehensively evaluated the potential short-term and long-term exposure effects of high salinity discharges from the WBMWD ocean water desalination demonstration facility (OWDDF) on aquatic organisms representative of communities indigenous to various near shore environments in Southern California. Short-term effects were evaluated using Whole Effluent Toxicity (WET) bioassays developed by the U.S. Environmental Protection Agency (USEPA) to quantify the magnitude and threshold of potential biological effects of discharges (e.g. treated wastewater). Both acute toxicity (mortality effects) and chronic toxicity (mortality + sublethal effects) bioassays were performed by a state accredited bioassay laboratory. Long-term effects were evaluated using mesocosm procedures performed at the OWDDF by exposing multiple organisms for eight weeks to ambient seawater and diluted brine flows from the OWDDF in large aquaria constructed to simulate the OWDDF discharge environment.

High‐resolution surface water dynamics in Earth’s small and medium‐sized reservoirs

Nature Portfolio (Springer Nature) | August 12th, 2022

Small and medium‐sized reservoirs play an important role in water systems that need to cope with climate variability and various other man‐made and natural challenges

Small and medium‐sized reservoirs play an important role in water systems that need to cope with climate variability and various other man‐made and natural challenges. Although reservoirs and dams are criticized for their negative social and environmental impacts by reducing natural flow variability and obstructing river connections, they are also recognized as important for social and economic development and climate change adaptation. Multiple studies map large dams and analyze the dynamics of water stored in the reservoirs behind these dams, but very few studies focus on small and medium‐sized reservoirs on a global scale. In this research, we use multi‐annual multi‐sensor satellite data, combined with cloud analytics, to monitor the state of small (10–100 ha) to medium‐ sized (> 100 ha, excluding 479 large ones) artificial water reservoirs globally for the first time. These reservoirs are of crucial importance to the well‐being of many societies, but regular monitoring records of their water dynamics are mostly missing. We combine the results of multiple studies to identify 71,208 small to medium‐sized reservoirs, followed by reconstructing surface water area changes from satellite data using a novel method introduced in this study. The dataset is validated using 768 daily in‐situ water level and storage measurements (r2 > 0.7 for 67% of the reservoirs used for the validation) demonstrating that the surface water area dynamics can be used as a proxy for water storage dynamics in many cases. Our analysis shows that for small reservoirs, the inter‐annual and intra‐annual variability is much higher than for medium‐sized reservoirs worldwide. This implies that the communities reliant on small reservoirs are more vulnerable to climate extremes, both short‐term (within seasons) and longer‐term (across seasons). Our findings show that the long‐term inter‐annual and intra‐annual changes in these reservoirs are not equally distributed geographically. Through several cases, we demonstrate that this technology can help monitor water scarcity conditions and emerging food insecurity, and facilitate transboundary cooperation. It has the potential to provide operational information on conditions in ungauged or upstream riparian countries that do not share such data with neighboring countries. This may help to create a more level playing field in water resource information globally.

Highlights Central Valley Flood Protection Plan 2022 Update

California Department of Water Resources (DWR) | January 23rd, 2023

The 2022 Central Valley Flood Protection Plan Update was adopted by the Central Valley Flood Protection Board on December 16th, 2022. Just days later, beginning on Decemb

The 2022 Central Valley Flood Protection Plan Update was adopted by the Central Valley Flood Protection Board on December 16th, 2022. Just days later, beginning on December 27th, 2022, a series of atmospheric rivers began to impact California. This succession of atmospheric rivers resulted in 34 trillion gallons of water falling across California in 24 days, and 21 forecast points in the Central Valley reaching flood or monitor stage. Governor Gavin Newsom declared a state of emergency on January 4th, 2023; federal emergency and disaster declarations followed soon thereafter. These events underscore the importance of the CVFPP as the State’s strategic blueprint for investment in flood risk reduction in the Central Valley, especially in an era of whiplash weather—from drought to flooding— driven by the impacts of climate change.

Hillslope Stability and Land Use

American Geophysical Union (AGU) | January 1st, 1985

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 11. This monograph compiles research findings on soil mass movement

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 11. This monograph compiles research findings on soil mass movement into a format usable by practitioners and students. Applications are stressed in the areas of extensive and management practices rather than engineering earthworks. Examples are included to illustrate various prediction, avoidance, and control measures used in managing unstable terrain. We use the term soil (i.e., soil mass movement) to mean the mantle of unconsolidated or poorly consolidated material of either residual or transported origin, that overlies bedrock and forms the surface of the land. This usage is consistent with the conventional civil engineering use of the word and is synonymous with the geological term regolith and with soil mantle.

Historical and future relations between large storms and droughts in California

University of California, Davis (UC Davis) | July 14th, 2016

California precipitation varies more dramatically from year to year than elsewhere in the conterminous United States. This paper analyzes the extent to which contribution

California precipitation varies more dramatically from year to year than elsewhere in the conterminous United States. This paper analyzes the extent to which contributions of the wettest days to overall precipitation dictate the state’s precipitation seasonality and frequent multiyear periods of drought (as precipitation deficit) and plenty is analyzed, historically and in projections of future climates. The wettest 5% of wet days in California contribute about a third of precipitation but about two-thirds of the variance of water-year precipitation. Year-to-year fluctuations in precipitation strongly reflect year-to-year fluctuations of contributions from the largest storms, with the large-storm contributions explaining about twice as much precipitation fluctuation as do contributions from all remaining storms combined. This extreme dominance of large storms is largely unique to California within the United States. In climate-change projections, eight of ten climate models considered here yield increases in precipitation from the largest storms, and when the increases are large, total precipitation follows suit. All of the models project declines in contributions from the smaller storms and models projecting total-precipitation declines reflect this decline. Projected changes in variance of water-year precipitation reflect changes in variance of large-storm contributions. The disproportionately large overall contributions from California’s largest storms, and their outsized year-to-year variability, ensure that the state’s largest storms dictate the state’s regimes of wet and dry spells, historically and in climate-change projections.

Historical Ecology and Landscape Change in the Central Laguna de Santa Rosa

San Francisco Estuary Institute (SFEI) | May 12th, 2017

This study synthesizes a diverse array of data to examine the ecological patterns, ecosystem functions, and hydrology that characterized a central portion of the Laguna d

This study synthesizes a diverse array of data to examine the ecological patterns, ecosystem functions, and hydrology that characterized a central portion of the Laguna de Santa Rosa during the mid-19th century, and to analyze landscape changes over the past 150 years. The primary purpose of this study was to help guide restoration actions and other measures aimed at reducing nutrient loads within this portion of the Laguna de Santa Rosa watershed. Prior to Euro-American modification of the landscape, the Laguna de Santa Rosa (hereafter, “Laguna”) supported a diverse and extensive array of wetland and riparian habitat types ranging from tule marshes and willow forests to wet meadows and vernal pools. As one of the largest wetland complexes in northern California, the Laguna was a productive ecosystem that was home to vast numbers of resident and migratory birds, fish, mammals, and other wildlife. It was this diversity and productivity that made the Laguna a focal element of the Santa Rosa Plain for generations of native Pomo people, and for 19th-century Spanish and American settlers. Today, the Laguna continues to provide vital habitat for a host of native plants and animals, and has been recognized by the Ramsar Convention on Wetlands as a Wetland of International Importance (Ramsar 2017). However, as the population of the area has grown and land use modifications have intensified over the past 150 years, the Laguna has experienced a variety of impacts stemming from urban and agricultural development. These impacts include substantial loss of native wetland and riparian habitats, channelization of streams, alterations to streamflow and sediment dynamics, invasion of non-native species, and water quality impairments. While the Laguna still exhibits elements of its former character, the modern Laguna represents a landscape profoundly altered by over a century and a half of both direct and indirect modifications. As residents and land managers look to improve the ecological health of the Laguna and restore lost ecological functions, an understanding of what the landscape was like in the recent past, and how it has changed over time, provides a valuable starting place for envisioning its future potential.

Historical Ecology and Landscape Change in the Central Laguna de Santa Rosa

San Francisco Estuary Institute (SFEI) | March 1st, 2017

This study synthesizes a diverse array of data to examine the ecological patterns, ecosystem functions, and hydrology that characterized a central portion of the Laguna d

This study synthesizes a diverse array of data to examine the ecological patterns, ecosystem functions, and hydrology that characterized a central portion of the Laguna de Santa Rosa during the mid-19th century, and to analyze landscape changes over the past 150 years. The primary purpose of this study was to help guide restoration actions and other measures aimed at reducing nutrient loads within this portion of the Laguna de Santa Rosa watershed.