California Aqueduct Subsidence Study

California Department of Water Resources (DWR) | June 1st, 2017

In 2006, the San Luis Field Division of the California Department of Water Resources' Division of Operations and Maintenance (O&M) began to see a reduction in flow ca

In 2006, the San Luis Field Division of the California Department of Water Resources' Division of Operations and Maintenance (O&M) began to see a reduction in flow capacity through the California Aqueduct (Aqueduct) Pools 20 and 21. Subsidence had lowered portions of the Aqueduct and caused the concrete liner freeboard (the vertical distance between the water surface and the top of the concrete liner) to be reduced from its normal of 3 feet, to less than 1 foot. Subsidence had also decreased the ability to store water in those pools, which is normally done to add operational flexibility and to manage pumping at the Aqueduct’s pumping plants. While subsidence has reduced the amount of freeboard and flow capacity at specific locations, contracted deliveries have not been curtailed through 2016. Additional work, to be addressed in the next phase of the project, will quantify how hydraulic limitations have impacted operations and will estimate future impacts to deliveries, based on forecasted subsidence rates. The purpose of this project is to research and study past and present subsidence reports and data, and to understand and summarize the magnitude, location, and effects on the Aqueduct. This report summarizes the significant information found, and presents the results of the data that were analyzed.

California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project: Domestic-Supply Assessment

U.S. Geological Survey (USGS) | March 14th, 2024

California Subsidence Program - Subsidence and Groundwater Monitoring Project

California Department of Water Resources (DWR) | June 21st, 2024

This Initial Study (IS) and Mitigated Negative Declaration (MND) has been prepared by the California Department of Water Resources (DWR) to address the environmental impa

This Initial Study (IS) and Mitigated Negative Declaration (MND) has been prepared by the California Department of Water Resources (DWR) to address the environmental impacts of the proposed California Aqueduct Subsidence Program (CASP) Subsidence and Groundwater Monitoring Project (proposed project) and to satisfy the requirements of the California Environmental Quality Act (CEQA). The DWR is planning installation of equipment to collect spatial information at approximately five (5) groundwater and subsidence monitoring stations along the California Aqueduct (Aqueduct) (approximately Mile Posts 213.0L, 230.6L, 259.6L, 271.2L, and 279.1L within the San Joaquin Field Division) (Figure 1). The proposed project would provide real-time data to monitor groundwater levels and other spatial information as they relate to ground subsidence. The data would be used to help inform how subsidence is affecting the Aqueduct and would assist in maintaining infrastructure of the State Water Project (SWP). The proposed project is described in more detail in Chapter 2.

California's Central Valley Groundwater Wells Run Dry During Recent Drought

American Geophysical Union (AGU) | February 27th, 2020

Declining water tables are causing wells to run dry in California, but the prevalence and spatial distribution of wells that have run dry are not known beyond anecdotal a

Declining water tables are causing wells to run dry in California, but the prevalence and spatial distribution of wells that have run dry are not known beyond anecdotal and voluntary reports. Here, we apply a new, simple, and measurement‐driven method to calculate a localized water table; we show, for the first time using observations, that up to one‐in‐five wells now runs dry in California's Central Valley. The spatial distribution of wells identified as having dried up replicates hot spots of wells identified as having run dry in a voluntary reporting system, while also capturing impacts on groundwater wells that have not reportedly run dry. We assess the rates of drilling throughout the Central Valley and find, surprisingly, that domestic wells are being drilled deeper at a rate that exceeds agricultural wells across much of the central Central Valley. Because new groundwater wells are costly (i.e., $10,000 to $100,000), we suggest explicitly considering dry wells in groundwater sustainability planning to protect homes and farms from the loss of access to reliable water supplies in the future.

California’s Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California’s Central Valley

U.S. Geological Survey (USGS) | June 16th, 2009

Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley’s population has nearly

Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley’s population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento–San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource. The U.S. Geological Survey (USGS) has released results from a study on the largest water reservoir in the State of California, the Central Valley groundwater system. The findings show continued loss of stored groundwater in the southern part of the valley (see figure below). Since about 1960, groundwater has been depleted by almost 60 million acre-feet, which is, on average, enough to supply every resident of California with water for 8 years. In order to complete the study, the USGS developed an extensive, detailed three-dimensional (3D) computer model of the hydrologic system of the Central Valley (Faunt, 2009). The Central Valley Hydrologic Model (CVHM) simultaneously accounts for changing water supply and demand across the landscape, and simulates surface water and groundwater flow across the entire Central Valley. This new hydrologic modeling tool can be used by water managers to understand how water moves through the aquifer system, predict water-supply scenarios, and address issues related to water competition in California and the Central Valley including: Conjunctive water use (interdependent use of surface water and groundwater); Conservation of agricultural land; Land-use change, including environmental concerns and urbanization, and its effects on water resources; and Effects of climate change.

California’s groundwater overdraft: An environmental Ponzi scheme?

Journal of Hydrology (Elsevier) | January 23rd, 2023

Groundwater levels have been decreasing in most agricultural areas, motivating research to find optimal solutions to balance socio-economical and environmental demands. T

Groundwater levels have been decreasing in most agricultural areas, motivating research to find optimal solutions to balance socio-economical and environmental demands. Traditionally, groundwater optimization aims at long-term profit maximization, while accounting for the extraction costs. Following this approach, we find exploitation protocols characterized by pumping rates that slowly decrease in time toward a long-term sustainable value. However, the comparison of the model prediction with water extraction data for the period 1985–2021 from Kern County in California points out the inconsistencies between real management and long-term optimal behavior. Rather, the observed trajectory resembles those obtained by finite-time optimization horizons, which provide short-term high profits by over-drafting, while leading to long-term dilapidation of the capital and the exhaustion of the aquifer. Such myopic planning results in a Ponzi scheme for groundwater extraction. Like the infamous fraudulent scheme, ‘more-than-optimal’ profits are achievable by excessive short-term consumption by the early investors (the past and current aquifer exploiters), leaving the later comers (the future generations) with an impossible cost to sustain. Including the environmental costs of aquifer over-exploitation, the myopic nature of human planning can be corrected and reconciled with a more sustainable use of groundwater.

Castac Lake Valley Groundwater Sustainability Plan

Castac Basin Groundwater Sustainability Agency | September 17th, 2020

The Castac Lake Valley Groundwater Basin (also referred to herein as “the Basin”), California Department of Water Resources (DWR) Basin No. 5-029, is located at the

The Castac Lake Valley Groundwater Basin (also referred to herein as “the Basin”), California Department of Water Resources (DWR) Basin No. 5-029, is located at the southern end of Kern County. The Basin is identified by DWR as being a very low priority basin, and as such, this GSP and associated SGMA compliance efforts have been conducted on a voluntary basis. Due to size, the file has been divided into two parts. Part 1, Part 2

Central Kings Groundwater Sustainability Agency Groundwater Sustainability Plan

Central Kings Groundwater Sustainability Agency (CKGSA) | December 11th, 2019

Central Kings Groundwater Sustainability Agency Groundwater Sustainability Plan (Revised)

Central Kings Groundwater Sustainability Agency (CKGSA) | July 13th, 2022

Central Valley Flood Protection Plan (2012)

California Department of Water Resources (DWR) | June 12th, 2012

The Central Valley Flood Protection Plan (CVFPP) is a critical document to guide California’s participation (and influence federal and local participation) in managing

The Central Valley Flood Protection Plan (CVFPP) is a critical document to guide California’s participation (and influence federal and local participation) in managing flood risk along the Sacramento River and San Joaquin River systems. The CVFPP proposes a system-wide investment approach for sustainable, integrated flood management in areas currently protected by facilities of the State Plan of Flood Control (SPFC). The CVFPP will be updated every five years, with each update providing support for subsequent policy, program, and project implementation. The State of California (State) conducted planning and investigations for the 2012 CVFPP from 2009 through 2011, representing the most comprehensive flood evaluations for the Central Valley. Following the anticipated adoption of the CVFPP in 2012 by the Central Valley Flood Protection Board (Board), preparation of regional- and State-level financing plans will guide investments in the range of $14 billion to $17 billion during the next 20 to 25 years.  These financing plans are critical to CVFPP implementation, given the uncertainty in State, federal, and local agency budgets and cost-sharing capabilities.