Los Angeles Department of Water and Power 2018 Annual Owens Valley Report

Los Angeles Department of Water & Power (LADWP) | December 1st, 2017

This report includes Los Angeles Department of Water and Power’s (LADWP) proposed Owens Valley Operations Plan for the 2018-2019 Runoff Year, an update on Owens Valley

This report includes Los Angeles Department of Water and Power’s (LADWP) proposed Owens Valley Operations Plan for the 2018-2019 Runoff Year, an update on Owens Valley conditions, and the current status of LADWP’s environmental mitigation projects and other legal obligations under the Agreement between the County of Inyo and the City of Los Angeles and its Department of Water and Power on a Long-Term Groundwater Management Plan for Owens Valley and Inyo County (Water Agreement); the 1991 Environmental Impact Report Water from the Owens Valley to Supply the Second Los Angeles Aqueduct, 1970 to 1990, 1990 Onward, Pursuant to a Long Term Groundwater Management Plan (1991 EIR); the Laws Type E transfer; the 1997 Memorandum of Understanding between the City of Los Angeles Department of Water and Power, County of Inyo, the California Department of Fish and Game, the California State Lands Commission, the Sierra Club, and the Owens Valley Committee (1997 MOU), the August 2004 and March 2010 Amended Stipulations and Orders in Case No. S1CVCV01-29768.

Los Osos Community Services District v. Golden State Water Company

Superior Court of California, County of San Luis Obispo | October 14th, 2015

This Stipulated Judgment concerns the Los Osos Groundwater Basin, as it is more particularly described in Sections 1.4.2 and 2.1 of this Stipulated Judgment, which underl

This Stipulated Judgment concerns the Los Osos Groundwater Basin, as it is more particularly described in Sections 1.4.2 and 2.1 of this Stipulated Judgment, which underlies the unincorporated communities of Los Osos, Baywood Park and Cuesta-by-the-Sea in San Luis Obispo County, California (“Basin”). The Basin is the only source of water for residential, commercial, institutional and agricul-tural development on properties overlying the Basin. This litigation (the “Action”) relates to efforts by the parties to sustainably manage the water resources of the Basin and to protect and promote the economic, environmental and social health of the community.

Los Osos Valley Groundwater Basin Fringe Areas Characterization

San Luis Obispo County Flood Control and Water Conservation District | May 22nd, 2018

The Sustainable Groundwater Management Act (SGMA) took effect on January 1, 2015, and requires that certain actions be taken in groundwater basins designated as either hi

The Sustainable Groundwater Management Act (SGMA) took effect on January 1, 2015, and requires that certain actions be taken in groundwater basins designated as either high or medium priority by the California Department of Water Resources (DWR), including Los Osos Basin. DWR identified the Los Osos Basin as a high priority basin subject to critical conditions of overdraft due to seawater intrusion and nitrate impairment (DWR, 2014, 2016). SGMA does not apply to the Los Osos Basin area that is at issue in Los Osos Community Services District v. Southern California Water Company [Golden State Water Company], et al.1 (Adjudicated Plan Area), for which a Stipulated Judgment was approved in San Luis Obispo Superior Court on October 14, 2015. The boundaries of the Adjudicated Plan Area do not coincide with the Basin boundaries as documented in DWR’s Interim Update to Bulletin 118 (2016). The groundwater basin areas between the Bulletin 118 Basin boundaries (Basin 3‐8) and the Adjudicated Plan Area boundary are referred to as “Fringe Areas” (Figure 1). In order to comply with SGMA, the County of San Luis Obispo (County) formed the Groundwater Sustainability Agency (GSA) over these Fringe Areas on April 4, 2017. The results of this basin characterization study are intended to produce a basis of knowledge for use in boundary modification requests and potential future use in development of a Groundwater Sustainability Plan (GSP). Decades of technical studies on the basin have focused primarily on aquifers within the Adjudicated Plan Area. This technical memorandum supplements prior work, which together provide a comprehensive hydrogeologic characterization and conceptual model of the Fringe Areas.

Lower Mill Creek Watershed Conjunctive Use Project: Tehama County, California

California Department of Water Resources (DWR) | November 18th, 2008

In 1920, the Tehama County Superior Court of the State of California adjudicated entitlements to all Mill Creek flow below 203 cubic feet per second (cfs). As such, water

In 1920, the Tehama County Superior Court of the State of California adjudicated entitlements to all Mill Creek flow below 203 cubic feet per second (cfs). As such, water right holders on Mill Creek legally divert a significant portion of the surface water flow for agricultural beneficial use. During certain times of the year, especially during dry or critically dry years, the agricultural demand for surface water can reduce Mill Creek flow and expose in-stream barriers to fish migration. Fishery experts recognize Mill Creek as a high priority stream for the protection and enhancement of Chinook salmon spawning habitat. Mill Creek surface water diverters currently participate in a long-term cooperative management plan to help provide sufficient flow for fish migration while also maintaining irrigation supplies and the recognition of surface water rights. As part of these efforts, Mill Creek water users participate in water lease and groundwater exchange programs designed to increase in-stream flow during critical spring and fall fish migration periods. Along with other entities, the Department of Water Resources (DWR) plans to establish methods of monitoring and studying fish passage, assessing agricultural water use efficiency, and examining the potential for additional use of groundwater as opposed to use of surface water diversions in the Lower Mill Creek watershed. This report provides a background of the geology and hydrogeology in the Lower Mill Creek watershed area, a detailed discussion of the groundwater resources, and an overview of the potential for conjunctive use of surface water and groundwater resources. It also provides recommendations for additional groundwater monitoring and potentially favorable locations for production well installation associated with possible future conjunctive use programs.

Lower Tule River Irrigation District Groundwater Sustainability Agency Groundwater Sustainability Plan

Lower Tule River Irrigation District Groundwater Sustainability Agency | January 21st, 2020

Lower Tule River Irrigation District Groundwater Sustainability Plan San, Joaquin - Tule Subbasin

Lower Tule River Irrigation District Groundwater Sustainability Agency | July 19th, 2023

This Plan addresses the items identified in the SGMA regulations specific to the Agency, including descriptions of the physical characteristics, the water budget (histor

This Plan addresses the items identified in the SGMA regulations specific to the Agency, including descriptions of the physical characteristics, the water budget (historic and future), specific monitoring features and locations, quantifiable targets and minimum thresholds for depth to groundwater, groundwater storage, groundwater quality, and land subsidence between 2020 and 2040, and those projects and management actions proposed to implement during the 20 year planning horizon to achieve the Sustainability Goal.

Machine learning based downscaling of GRACE-estimated groundwater in Central Valley, California

Science of the Total Environment (Elsevier) | January 9th, 2023

California's Central Valley, one of the most agriculturally productive regions, is also one of the most stressed aquifers in the world due to anthropogenic groundwater ov

California's Central Valley, one of the most agriculturally productive regions, is also one of the most stressed aquifers in the world due to anthropogenic groundwater over-extraction primarily for irrigation. Groundwater depletion is further exacerbated by climate-driven droughts. Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry has demonstrated the feasibility of quantifying global groundwater storage changes at uniform monthly sampling, though at a coarse resolution and is thus impractical for effective water resources management. Here, we employ the Random Forest machine learning algorithm to establish empirical relationships between GRACE-derived groundwater storage and in situ groundwater level variations over the Central Valley during 2002–2016 and achieved spatial downscaling of GRACE-observed groundwater storage changes from a few hundred km to 5 km. Validations of our modeled groundwater level with in situ groundwater level indicate excellent Nash-Sutcliffe Efficiency coefficients ranging from 0.94 to 0.97. In addition, the secular components of modeled groundwater show good agreements with those of vertical displacements observed by GPS, and CryoSat-2 radar altimetry measurements and is perfectly consistent with findings from previous studies. Our estimated groundwater loss is about 30 km3 from 2002 to 2016, which also agrees well with previous studies in Central Valley. We find the maximum groundwater storage loss rates of −5.7 ± 1.2 km3 yr−1 and -9.8 ± 1.7 km3 yr−1 occurred during the extended drought periods of January 2007–December 2009, and October 2011–September 2015, respectively while Central Valley also experienced groundwater recharges during prolonged flood episodes. The 5-km resolution Central Valley-wide groundwater storage trends reveal that groundwater depletion occurs mostly in southern San Joaquin Valley collocated with severe land subsidence due to aquifer compaction from excessive groundwater over withdrawal.

Major carbon-14 anomaly in a regional carbonate aquifer—Possible evidence for megascale channeling, south-central Great Basin

American Geophysical Union (AGU) | December 1st, 1976

The carbon 14 content of groundwater at the center of a 16‐km‐long fault‐controlled spring line at Ash Meadows in south central Nevada is 5 times greater than that

The carbon 14 content of groundwater at the center of a 16‐km‐long fault‐controlled spring line at Ash Meadows in south central Nevada is 5 times greater than that in water from other major springs along the lineament. The difference in carbon 14 stands in marked contrast to the near identity of all springwaters in alkalinity, pH, carbon 13, oxygen 18, deuterium, tritium, and other major and trace ions. Ten possible explanations of this major carbon 14 anomaly are evaluated by using all available chemical and isotopic data from basin‐wide wells and upland springs tapping the regional carbonate aquifer discharging at Ash Meadows. The four most plausible hypotheses require the presence of a major longitudinal heterogeneity in the distal portion of the groundwater basin to explain the anomaly. Flow channeling with an amplitude of at least 11 km is indicated. The simplifying assumption commonly used in simulation of basin‐wide flow through fractured or solution‐riddled aquifers, namely, that the aquifer is ‘homogenous in its heterogeneity,’ is not applicable to the dense fractured Paleozoic carbonate rocks comprising the Nevada aquifer; heterogeneities in this aquifer do not cancel each other areally.

Major ground-water flow systems in the Great Basin region of Nevada, Utah, and adjacent state

U.S. Geological Survey (USGS) | July 1st, 1988

Majority of global river flow sustained by groundwater

Nature Portfolio (Springer Nature) | July 19th, 2024

Groundwater-sustained baseflow is a vital source of river flow, especially during dry seasons. The proportion of river flow sustained by baseflow—the baseflow index—i

Groundwater-sustained baseflow is a vital source of river flow, especially during dry seasons. The proportion of river flow sustained by baseflow—the baseflow index—is essential for assessing fluvial nutrient cycling and contaminant transport. However, the global baseflow index remains highly uncertain, with current Earth system model simulations ranging from 12% to 94%. Here we estimate the global baseflow index to be 59% ± 7% based on an emergent constraint approach, which integrates 50 Earth system models with baseflow indices derived from streamflow observations in 15,567 basins. Our observational constraint indicates that at least 21% ± 3% of precipitation recharges groundwater, which is approximately double the figure reported in the Sixth Assessment Report of the United Nations Intergovernmental Panel on Climate Change. Thus, our research suggests a more active role of groundwater in the global water cycle than most Earth system models currently simulate. We present evidence that the considerable disagreement in simulated baseflow stems from unrealistic and varied model representations of infiltration, aquifer structure and groundwater dynamics. These processes should be prioritized so that models can capture active groundwater–river connections.