Seawater intrusion processes, investigation and management: Recent advances and future challenges

Advances in Water Resources (Elsevier) | January 17th, 2013

Seawater intrusion (SI) is a global issue, exacerbated by increasing demands for freshwater in coastal zones and predisposed to the influences of rising sea levels and ch

Seawater intrusion (SI) is a global issue, exacerbated by increasing demands for freshwater in coastal zones and predisposed to the influences of rising sea levels and changing climates. This review presents the state of knowledge in SI research, compares classes of methods for assessing and managing SI, and suggests areas for future research. We subdivide SI research into categories relating to processes, measurement, prediction and management. Considerable research effort spanning more than 50 years has provided an extensive array of field, laboratory and computer-based techniques for SI investigation. Despite this, knowledge gaps exist in SI process understanding, in particular associated with transient SI processes and timeframes, and the characterization and prediction of freshwater–saltwater interfaces over regional scales and in highly heterogeneous and dynamic settings. Multidisciplinary research is warranted to evaluate interactions between SI and submarine groundwater discharge, ecosystem health and unsaturated zone processes. Recent advances in numerical simulation, calibration and optimization techniques require rigorous field-scale application to contemporary issues of climate change, sea-level rise, and socioeconomic and ecological factors that are inseparable elements of SI management. The number of well-characterized examples of SI is small, and this has impeded understanding of field-scale processes, such as those controlling mixing zones, saltwater upconing, heterogeneity effects and other factors. Current SI process understanding is based mainly on numerical simulation and laboratory sand-tank experimentation to unravel the combined effects of tides, surface water–groundwater interaction, heterogeneity, pumping and density contrasts. The research effort would benefit from intensive measurement campaigns to delineate accurately interfaces and their movement in response to real-world coastal aquifer stresses, encompassing a range of geological and hydrological settings.

Second Amended Delano-Earlimart Irrigation District Groundwater Sustainability Plan 2024

Delano-Earlimart Irrigation District Groundwater Sustainability Agency (DEID GSA) | July 1st, 2024

In January of 2020, the DEID GSA submitted its Groundwater Sustainability Plan (GSP) to the California Department of Water Resources (DWR). The GSP provided technical doc

In January of 2020, the DEID GSA submitted its Groundwater Sustainability Plan (GSP) to the California Department of Water Resources (DWR). The GSP provided technical documentation of the DEID Management Area’s existing sustainability, along with addressing the needs of the Earlimart Public Utility District and Richgrove Community Services District. The GSP outlined specific management actions that will be taken in accordance with the Sustainable Groundwater Management Act. DWR’s review of the Tule Subbasin, as a whole, resulted in an incomplete determination, to which the GSAs in the Tule Subbasin had 180 days to respond. The GSA’s in the Tule Subbasin provided revised GSPs on July 27, 2022, which DWR also determined were inadequate, causing the Tule Subbasin to transition to the oversight of the State Water Resources Control Board (SWRCB). The draft GSP found below includes updates to specifically address comments received from the SWRCB and their staff in anticipation of the Tule Subbasin probationary hearing on September 17, 2024. Comments on the 2nd amended GSP can be submitted to info@deid.org and will be accepted through August 18, 2024. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6

Second Report of Recharge Parties Pursuant to RWQCB Resolution No. R8-2008-0019 Cooperative Agreement to Protect Water Quality and Encourage the Conjunctive Uses of Imported Water in the Santa Ana River Basin, Yucaipa and San Timoteo Management Zones

San Bernardino Valley Municipal Water District | July 18th, 2012

The importation of water (i.e., State Water Project (SWP) water, Colorado River water, and imported groundwater) to groundwater basins within the Santa Ana River Region

The importation of water (i.e., State Water Project (SWP) water, Colorado River water, and imported groundwater) to groundwater basins within the Santa Ana River Region is necessary to meet increasing demand. However, long-term conjunctive use of water within the Region could affect groundwater quality. As such, the California Regional Water Quality Control Board Santa Ana Region (RWQCB) is requiring that groundwater quality be managed to meet the water quality objectives for total dissolved solids (TDS) and nitrogen (i.e., Salinity Objectives) regulated in the 1995 Water Quality Control Plan for the Santa Ana River Basin (Basin Plan). On January 22, 2004, the RWQCB adopted Resolution No. R8-2004-0001, incorporating an updated TDS and nitrogen management plan that includes revised groundwater subbasin boundaries; revised TDS and nitrate-nitrogen water quality objectives for groundwater; revised TDS and nitrogen waste load allocations; and revised reach designations, TDS and nitrogen objectives and beneficial uses for specific surface waters. On May 19, 2006, the RWQCB considered a resolution and order that would have adopted general waste discharge requirements for the recharge of imported water to the Santa Ana River Basin. Based on input from stakeholders, it was decided by the RWQCB that the feasibility of a cooperative program should be investigated that would achieve the objectives of and obviate the adoption of the draft resolution and order under consideration. On January 18, 2008, the RWQCB adopted Resolution No. R8-2008-0019 authorizing a “Cooperative Agreement to Protect Water Quality and Encourage the Conjunctive Use of Imported Water in the Santa Ana River Basin.” The purpose of the cooperative agreement is to allow the participating parties to “…monitor and improve water quality objectives within the Santa Ana River Region in a manner that is consistent with the needs of the inhabitants of the Region for a reliable supply of water.” (Cooperative Agreement, 2008). The following Parties have entered into this cooperative agreement: California Regional Water Quality Control Board, Santa Ana Region, City of Corona, City of Riverside, City of San Bernardino Municipal Water Department, Eastern Municipal Water District, Elsinore Valley Municipal Water District, Orange County Water District, San Bernardino Valley Municipal Water District (Valley District), San Gorgonio Pass Water Agency, and Western Municipal Water District of Riverside County (Western).  

Second Supplement to State Water Resources Board Bulletin No. 11, San Joaquin County Investigation, Basic Data, Calaveras Unit, 1955-56

California Department of Water Resources (DWR) | April 20th, 1957

Selected Techniques for Monitoring Water Movement Through Unsaturated Alluvium During Managed Aquifer Recharge

U.S. Geological Survey (USGS) | October 21st, 2016

Managed aquifer recharge is used to augment natural recharge to aquifers. It can be used to replenish aquifers depleted by pumping or to store water during wetter years f

Managed aquifer recharge is used to augment natural recharge to aquifers. It can be used to replenish aquifers depleted by pumping or to store water during wetter years for withdrawal during drier years. Infiltration from ponds is a commonly used, inexpensive approach for managed aquifer recharge. At some managed aquifer recharge sites, the time when infiltrated water arrives at the water table is not always clearly shown by water-level data (fig. 1). As part of site characterization and operation, it can be desirable to track downward movement of infiltrated water through the unsaturated zone to identify when it arrives at the water table.

Selected trace-elements in alluvium and rocks, western Mojave Desert, southern California

Journal of Geochemical Exploration (Elsevier) | September 3rd, 2018

Concentrations of twenty-seven elements, including naturally-occurring water-quality contaminants arsenic, chromium, and uranium, were measured in 217 samples of alluviu

Concentrations of twenty-seven elements, including naturally-occurring water-quality contaminants arsenic, chromium, and uranium, were measured in 217 samples of alluvium and rock from the western Mojave Desert, southern California, using portable (pXRF) and laboratory (LXRF) X-ray fluorescence. Comparison of measurements with NIST-traceable standards was good, although pXRF overestimated iron compared to LXRF. Results suggest pXRF survey data are sufficiently accurate to assess regional geochemical differences in geologic-source terrains. Principal component analysis showed rubidium and potassium were associated with alluvium eroded from felsic terrain, while iron, copper, chromium, and to a lesser extent titanium, manganese, and nickel were associated with alluvium eroded from mafic terrain. Zinc, vanadium, and arsenic were associated with alluvium eroded from hydrothermal terrain. Elemental assemblages associated with different source terrains were traced spatially to identify the source and composition of alluvium composing aquifers pumped for water supply. Changes in geologic source terrain to the Mojave River, associated with movement along the San Andreas Fault over the past one to five million years, reduced the mafic fraction and increased the felsic fraction of alluvium deposited to the regionally important floodplain aquifer along the Mojave River—lowering chromium concentrations in alluvium through geologic time. Comparison of pXRF and sequential extraction data from 40samples showed arsenic and uranium were more abundant on the surfaces of mineral grains, while chromium and vanadium remained mostly within unweathered mineral grains—suggesting arsenic and uranium may be more readily mobilized into groundwater with changes in pH, redox, or ionic strength than chromium or vanadium.

Sensing the ups and downs of Las Vegas: InSAR reveals structural control of land subsidence and aquifer-system deformation

Geological Society of America (GSA) | June 1st, 1999

Land subsidence in Las Vegas, Nevada, United States, between April 1992 and December 1997 was measured using spaceborne interferometric synthetic aperture radar. The deta

Land subsidence in Las Vegas, Nevada, United States, between April 1992 and December 1997 was measured using spaceborne interferometric synthetic aperture radar. The detailed deformation maps clearly show that the spatial extent of subsidence is controlled by geologic structures (faults) and sediment composition (clay thickness). The maximum detected subsidence during the 5.75 yr period is 19 cm. Comparison with leveling data indicates that the subsidence rates declined during the past decade as a result of rising ground-water levels brought about by a net reduction in ground-water extraction. Temporal analysis also detects seasonal subsidence and uplift patterns, which provide information about the elastic and inelastic properties of the aquifer system and their spatial variability.

Sensing the ups and downs of Las Vegas: InSAR reveals structuralcontrol of land subsidence and aquifer‐system deformation

Geological Society of America (GSA) | June 1st, 1999

Land subsidence in Las Vegas, Nevada, United States, between April 1992 and December 1997 was measured using spaceborne interferometric synthetic aperture radar. The deta

Land subsidence in Las Vegas, Nevada, United States, between April 1992 and December 1997 was measured using spaceborne interferometric synthetic aperture radar. The detailed deformation maps clearly show that the spatial extent of subsidence is controlled by geologic structures (faults) and sediment composition (clay thickness). The maximum detected subsidence during the 5.75 yr period is 19 cm. Comparison with leveling data indicates that the subsidence rates declined during the past decade as a result of rising ground-water levels brought about by a net reduction in ground-water extraction. Temporal analysis also detects seasonal subsidence and uplift patterns, which provide information about the elastic and inelastic properties of the aquifer system and their spatial variability.

SGMA Alternative Groundwater Sustainability Plan – Bridge Document for the Indio Subbasin

Coachella Valley Water District (CVWD) | December 15th, 2016

Decline in the Coachella Valley’s groundwater table was first noted in the 1910s. Concerned that their artesian wells were drying, local residents and farmers formed th

Decline in the Coachella Valley’s groundwater table was first noted in the 1910s. Concerned that their artesian wells were drying, local residents and farmers formed the Coachella Valley Water District (CVWD) in 1918. CVWD took steps to secure water supplies from the Colorado River that led to the completion of the Coachella Branch of the All-American Canal in 1949. CVWD and Desert Water Agency (DWA) contracted with the State of California for water from the State Water Project (SWP) in the early 1960s with the first deliveries in 1973. At that time, CVWD and DWA implemented groundwater replenishment programs and collected replenishment assessment from groundwater producers. However, continued growth in the Valley resulted in groundwater level declines and overdraft. Twenty years before the adoption of SGMA, CVWD began development of the initial Water Management Plan in 1994 after recognizing the need to sustainably manage the Coachella Valley Groundwater Basin. CVWD adopted the Coachella Valley Water Management Plan in 2002 (2002 WMP) to eliminate groundwater overdraft in the Basin. The 2002 WMP was updated in 2010 (2010 WMP Update) and adopted in 2012. This plan covers the Indio Subbasin of the Coachella Valley Groundwater Basin. CVWD, along with DWA and Mission Springs Water District also prepared the Mission Creek-Garnet Hill Water Management Plan (MCGH WMP) that covers the Mission Creek Subbasin and the Garnet Hill Subarea of the Indio Subbasin. As of 2016, plan implementation is showing positive results with stabilizing water levels throughout much of the Valley. Continued implementation is expected to eliminate water level declines by about 2025.

SGMA Alternative Groundwater Sustainability Plan Bridge Document for the Indio Subbasin

Coachella Valley Water District (CVWD) | December 29th, 2016