Hydrologic Extremes
Hydrologic Extremes
The effects of drought
Lake Shasta in Northern California showing low water levels during a recent drought.
Lake Shasta in Northern California showing low water levels during a recent drought.
Monitoring rivers and streams during high-water events
The Consumes River, near Sacramento, experienced record streamflow over the 2022 New Year's holiday weekend as an atmospheric river moved through northern California.
The Consumes River, near Sacramento, experienced record streamflow over the 2022 New Year's holiday weekend as an atmospheric river moved through northern California.
The aftermath of wildfire
Wildfires reduce the forest canopy, exposing snowpack to direct sunlight. This increases the rate of snowmelt and evaporation, impacting runoff and groundwater replenishment.
Wildfires reduce the forest canopy, exposing snowpack to direct sunlight. This increases the rate of snowmelt and evaporation, impacting runoff and groundwater replenishment.
Water is essential for all life on Earth, but too much water – or too little – can cause big problems. The USGS California Water Science Center studies a wide range of water-related hazards, from large storms and flooding to drought and post-wildfire runoff and helps communities plan for and respond to water-related emergencies.
Drought
Drought
The USGS closely monitors the effects of drought through data collection and research, supporting successful planning and science-based decision-making by water managers who must address complex issues and competing interests in times of drought.
Floods
Floods
The USGS maintains a network of nearly 500 streamgages in California that delivers a continuous source of streamflow data. When water levels change rapidly, or reach flood-stage levels, flood-warning alerts are issued help emergency managers assess potentially hazardous conditions.
Wildfires
Wildfires
Wildfires pose considerable risks to water quality & quantity, which in turn affect water supplies, fisheries, & aquatic habitats. The USGS studies the effects past, current, & future wildfires have upon California's water resources.
Filter Total Items: 43
Effects of Climate on Snowmelt and Water Availability for Reservoirs in the Southern Sierra Nevada
Potential changes in air temperature and precipitation due to changes in climate may result in more variable or smaller snow packs and earlier snowmelt in the southern Sierra Nevada in upcoming years. These conditions are likely to result in increased difficulty in planning reservoir operations for hydroelectric power and water availability during springtime snowmelt in this region. Reservoir...
Investigation of Linkages Between Management Practices Used in Sacramento-San Joaquin Delta Rice Production and Loads of Dissolved Organic Matter and Disinfection Byproduct Precursors
The primary objective of this study is to expand our current understanding of how to manage rice production in the Sacramento-San Joaquin Delta in a manner that minimizes loads of water quality contaminants to Delta waters.
Geohydrology of the Big Bear Valley
The study develops a greater understanding of the hydrology of the Big Bear Valley ground-water basin and allows the Big Bear Valley Community Services District to better manage and utilize the resource. The study will address the effects of urbanization and suburbanization on water resources and the effects of climate on water resources, issues 1 and 7 from the Strategic Directions for the Water...
Spatially Explicit Mapping of Hydrologic Residence Time Paired with Water Quality Measurements to Determine the Effects of the Emergency Drought Barrier
The purpose of this study is to assess the distribution of water residence times across the central Delta using rapid water isotope measurements (δ2H, δ18O) made with a boat-based flow-through instrument.
Science Programs and Partnerships
The USGS partners with local, state, and other federal agencies through cooperative agreements for a variety of reasons. The USGS and partners jointly plan the scientific work conducted under cooperative agreements resulting in science that has broad relevance to address current water issues. Partners choose to work with the USGS because of the agency's broad technical expertise, its long-standing...
Mojave Land-Subsidence Studies
Land subsidence has been ongoing in the dry lake beds throughout the Mojave and Morongo groundwater basins since the 1960s. In a study conducted from 2004 - 2009, continuous GPS stations were added to interferometric synthetic aperture radar (InSAR) methods to measure changes in land surface altitude.
Bay Area Ensemble Modeling for Conservation and Biodiversity
The objective of this study is to provide downscaled ensemble projections of climate and hydrology for the next century for the state of California with specific application to the San Francisco Bay Area.
Development of unimpaired flows for mountain basins draining to the Bay Delta
The objective of this study is to develop daily historical climate surfaces and simulate unimpaired basin discharge, including surface water flow and baseflow, from all basins that drain to the Bay Delta. Basin drainage will be calibrated to DWR reconstructed flows, and comparisons of results will be made with other independently developed watershed models for basins in which they coincide. A...
Delta-Mendota Canal: Evaluation of Groundwater Conditions and Land Subsidence
In areas adjacent to the Delta-Mendota Canal (DMC), extensive groundwater withdrawal from the San Joaquin Valley aquifer system has caused areas of the ground to sink as much as 10 feet, a process known as land subsidence. This could result in serious operational and structural issues for the Delta-Mendota Canal (DMC). In response, the USGS is studying and providing information on groundwater...
Monitoring the Impacts of the Rim Fire on Tuolumne River Water Quality
The Rim Fire has burned over 400 square miles of the Tuolumne River and Merced River watersheds in central California and is now the 3rd largest wildfire in state history. The burn area is largely on the Tuolumne between Hetch Hetchy Reservoir and Don Pedro Reservoir, both of which serve as critical sources of drinking water and irrigation water to San Francisco Bay area and Central Valley...
Simulating Land Subsidence
The California Water Science Center has been involved in multiple studies simulating land subsidence associated with groundwater withdrawal. The simulations can be used to estimate the magnitude, location, and timing of subsidence. They can also be used to evaluate management strategies to mitigate adverse effects from subsidence while also optimizing water availability.
Using Numerical Models to Simulate Subsidence
The California Water Science Center has been involved in multiple studies simulating land subsidence associated with groundwater withdrawal. The simulations can be used to estimate the magnitude, location, and timing of subsidence. They can also be used to evaluate management strategies to mitigate adverse effects from subsidence while also optimizing water availability.