Land Subsidence

The USGS closely monitors the occurence and effects of drought through data collection and research. USGS science supports water managers in preparing for possible future drought by providing information about long-term hydrologic, climatic, and environmental changes. These studies support successful planning and science-based decision-making by water managers who must address complex issues and...

Blue carbon ecosystems (BCEs) are coastal ecosystems, such as tidal marshes, mangroves, and seagrasses, with manageable and atmospherically significant carbon stocks and fluxes. The tidal marshes and scrub-shrub wetlands in the Sacramento-San Joaquin Delta (Delta) of California are examples of BCEs. The Delta is a 2,400 square kilometer tidal freshwater region located at the landward end of the...

The MODFLOW One-Water Hydrologic Flow Model (MF-OWHM) – Conjunctive Use Simulation Software (Boyce, 2022; Boyce and others, 2020; Hanson and others, 2014) builds upon the MODFLOW-2005 framework for the simulation and analyses of conjunctive-use, water-management, and climate-crop-water scenario problems.

In 2014, the State of California adopted historic legislation to help manage its groundwater, the Sustainable Groundwater Management Act (SGMA) . According to the act, local Groundwater Sustainability Agencies (GSAs) must be formed for all high and medium priority basins in the state. These GSAs must develop and implement Groundwater Sustainability Plans (GSPs) for managing and using groundwater...

Reclamation's Yuma Area Office (YAO) operates 50 plus drainage wells and 21 regulatory wells to control groundwater levels in low-lying flood plain areas and to supply a significant portion of the Colorado River water the United States (US) is required by treaty to deliver to Mexico.

Residents and businesses in Yucca Valley, CA rely currently on septic tanks to treat their wastewater. The local water district, Hi-Desert Water District (HDWD), is planning to construct a sewer system and wastewater treatment plant, initially serving the West, Midwest, Mideast, Northeast, and East hydrogeologic units of the Warren subbasin.

Sonoma County faces potential changes in surface-water availability, including potential impacts on water quality in response to changing land use, increasing population, and climate change.

Groundwater has been the primary source of domestic, agricultural, and municipal water supplies in the southwestern Mojave Desert, California, since the early 1900s. The population of the Mojave River and Morongo groundwater basins has grown rapidly during the last several decades, increasing from an estimated population of almost 273,000 in 1990 (Mojave Water Agency, 2004) to more than 453,000 in...

Measurements of elevations, aquifer-system compaction, and water levels are used to improve our understanding of the processes responsible for land-surface elevation changes. Elevation or elevation-change measurements are fundamental to monitoring land subsidence, and have been measured by using continuous GPS (CGPS) measurements and campaign global positioning system (GPS) surveying.

Elevation or elevation-change measurements are fundamental to monitoring land subsidence, and have been measured by using interferometric synthetic aperture radar (InSAR), continuous GPS (CGPS) measurements, campaign global positioning system (GPS) surveying, and spirit-leveling surveying. The most precise measurements tend to be made using spirit-leveling surveys and extensometers. Spirit...

Interferometric Synthetic Aperture Radar (InSAR) is an effective way to measure changes in land surface altitude. InSAR makes high-density measurements over large areas by using radar signals from Earth-orbiting satellites to measure changes in land-surface altitude at high degrees of measurement resolution and spatial detail ( Galloway and others, 2000 ). Synthetic Aperture Radar (SAR) imagery is...

Throughout the late 1800s and into the 1920s when two thirds of the Santa Clara Valley had been irrigated, water flowed freely from wells. Water-level declines of more than 200 ft occurred in the Santa Clara Valley from the early 1900's to the mid 1960's (Fowler, 1981). Land subsidence was first detected in 1933 (Poland and Ireland, 1988). As the decades passed, groundwater levels continued to...