Over‐pumping leads to California groundwater arsenic threat

Nature Portfolio (Springer Nature) | June 5th, 2018

Water resources are being challenged to meet domestic, agricultural, and industrial needs. To complement finite surface water supplies that are being stressed b

Water resources are being challenged to meet domestic, agricultural, and industrial needs. To complement finite surface water supplies that are being stressed by changes in precipitation and increased demand, groundwater is increasingly being used. Sustaining groundwater use requires considering both water quantity and quality. A unique challenge for groundwater use, as compared with surface water, is the presence of naturally occurring contaminants within aquifer sediments, which can enter the water supply. Here we find that recent groundwater pumping, observed through land subsidence, results in an increase in aquifer arsenic concentrations in the San Joaquin Valley of California. By comparison, historic groundwater pumping shows no link to current groundwater arsenic concentrations. Our results support the premise that arsenic can reside within pore water of clay strata within aquifers and is released due to overpumping. We provide a quantitative model for using subsidence as an indicator of arsenic concentrations correlated with groundwater pumping.

Overpumping leads to California groundwater arsenic threat

Nature Portfolio (Springer Nature) | June 5th, 2018

Water resources are being challenged to meet domestic, agricultural, and industrial needs. To complement finite surface water supplies that are being stressed b

Water resources are being challenged to meet domestic, agricultural, and industrial needs. To complement finite surface water supplies that are being stressed by changes in precipitation and increased demand, groundwater is increasingly being used. Sustaining groundwater use requires considering both water quantity and quality. A unique challenge for groundwater use, as compared with surface water, is the presence of naturally occurring contaminants within aquifer sediments, which can enter the water supply. Here we find that recent groundwater pumping, observed through land subsidence, results in an increase in aquifer arsenic concentrations in the San Joaquin Valley of California. By comparison, historic groundwater pumping shows no link to current groundwater arsenic concentrations. Our results support the premise that arsenic can reside within pore water of clay strata within aquifers and is released due to overpumping. We provide a quantitative model for using subsidence as an indicator of arsenic concentrations correlated with groundwater pumping.

Owens Valley Groundwater Basin Final Groundwater Sustainability Plan

Owens Valley Groundwater Authority | December 9th, 2021

The Owens Valley Groundwater Basin and Fish Slough subbasin (Basin) were assigned a low priority status by the California Department of Water Resources (DWR) and are not

The Owens Valley Groundwater Basin and Fish Slough subbasin (Basin) were assigned a low priority status by the California Department of Water Resources (DWR) and are not required to be managed by a Groundwater Sustainability Agency (GSA). GSAs in low priority basins are encouraged to complete a GSP. Following the adoption of the Sustainable Groundwater Management Act (SGMA), the Basin was originally ranked as medium priority, but DWR proposed it be assigned high priority and ultimately ranked the Basin as low priority in December 2019. Despite the uncertainty in the Basin ranking before the final ranking was announced the Owens Valley Groundwater Authority (OVGA) elected to prepare a GSP for the Basin. This document is the GSP, and it was developed in accordance with Sustainable Groundwater Management Act (SGMA) statutory and regulatory requirements. This GSP describes the Basin, develops quantifiable management objectives that account for the interests of beneficial groundwater uses and users, and identifies a group of management actions that will maintain sustainable conditions in the Basin for 20 years after plan adoption. This GSP also contains steps a GSA could undertake to manage pumping to address declining water levels in a portion of the Basin. Preparation and implementation of the GSP by the OVGA is discretionary as long as the Basin remains very low or low priority. This GSP does not pertain to lands in the Basin that are exempt from SGMA, e.g. Federal and state owned lands, Tribal Reservations, and Los Angeles Department of Water and Power (LADWP) lands managed pursuant to the Long Term Water Agreement (LTWA). LADWP lands in Inyo County are referred to as adjudicated; other lands in the Basin are referred to as GSP lands in this document. Los Angeles-owned lands in the Basin in Mono County are not exempt from SGMA. Due to size, the file has been divided into five parts. Part 1, Part 2, Part 3, Part 4, Part 5

Pajaro Valley Basin Management Plan Groundwater Sustainability Update 2022

Pajaro Valley Water Management Agency (PVWMA) | November 17th, 2021

Pajaro Valley Water Management Agency Basin Management Plan Update

Pajaro Valley Water Management Agency (PVWMA) | February 14th, 2014

Pajaro Valley Water Management Agency Revised Management Plan

Pajaro Valley Water Management Agency (PVWMA) | February 14th, 2002

Paso Robles Subbasin Groundwater Sustainability Plan

Paso Robles Subbasin Cooperative Committee | November 13th, 2019

Paso Robles Subbasin Groundwater Sustainability Plan (Revised)

Paso Robles Subbasin Groundwater Sustainability Agencies | June 13th, 2022

This Groundwater Sustainability Plan (GSP) fulfills the requirements of the Sustainable Groundwater Management Act (SGMA) for the Paso Robles Subbasin of the Salinas Vall

This Groundwater Sustainability Plan (GSP) fulfills the requirements of the Sustainable Groundwater Management Act (SGMA) for the Paso Robles Subbasin of the Salinas Valley Basin. The sustainability goal of this GSP is to sustainably manage the groundwater resources of the Paso Robles Subbasin for long-term community, financial, and environmental benefit of Subbasin users. This GSP outlines the approach to achieve a sustainable groundwater resource free of undesirable results within 20 years, while maintaining the unique cultural, community, and business aspects of the Subbasin. In adopting this GSP, it is the express goal of the GSAs to balance the needs of all groundwater users in the Subbasin, within the sustainable limits of the Subbasin’s resources. The GSP describes the Paso Robles Subbasin, develops quantifiable management objectives that consider the interests of the Subbasin’s beneficial groundwater uses and users, and identifies management actions and conceptual projects that will allow the Subbasin to achieve sustainability by 2040. This GSP covers the entire Paso Robles Subbasin. The Paso Robles Subbasin GSP has been jointly developed by four Groundwater Sustainability Agencies (GSAs): • City of Paso Robles GSA • Paso Basin - County of San Luis Obispo GSA • San Miguel Community Services District (CSD) GSA • Shandon - San Juan GSA Submitted to the California Department of Water Resources (DWR) in January 2021, the first version of this GSP was reviewed by DWR in January 2022 and determined to be incomplete (DWR, 2022). Corrective actions were provided by DWR for two identified deficiencies; these corrective actions are incorporated into this June 13, 2022 GSP for resubmittal to DWR. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6

Paso Robles vineyard irrigation study provides benchmark data to assist future area groundwater management

California Agriculture (UCANR) | March 13th, 2018

Accurate information on irrigation water usage does not exist in many areas where groundwater is the primary water source. This lack of information will hinder

Accurate information on irrigation water usage does not exist in many areas where groundwater is the primary water source. This lack of information will hinder efforts to manage these groundwater basins sustainably according to current and future water regulations and policies. Using a low-cost methodology of irrigation-line pressure sensors connected to data loggers, we estimated irrigation applications at 84 vineyard sites in the Paso Robles Groundwater Basin over 4 years (2010–2013). We compared irrigation amounts with the preceding winter’s rainfall and with the growing season reference evapotranspiration (ETo). Over the study period, the average annual irrigation application was 11.46 inches (291 millimeters). The average annual application correlated inversely to the preceding winter’s rainfall, while the irrigation over the growing season (April–October) correlated directly with the ETo over this same period. This study provides an initial data framework that can be used by groundwater sustainability agencies to help manage groundwater in the Paso Robles area. The methodology also could be utilized in other regions to estimate regional irrigation usage while maintaining anonymity for participants.

Pesticides in the Nation’s Streams and Ground Water, 1992–2001

U.S. Geological Survey (USGS) | February 28th, 2006

This report is one of a series of publications, The Quality of Our Nation’s Waters, that describe major findings of the NAWQA Program on water-quality issues of regiona

This report is one of a series of publications, The Quality of Our Nation’s Waters, that describe major findings of the NAWQA Program on water-quality issues of regional and national concern. This report presents evaluations of pesticides in streams and ground water based on findings for the first decadal cycle of NAWQA. “Pesticides in the Nation’s Streams and Ground Water, 1992–2001” greatly expands the analysis of pesticides presented in “Nutrients and Pesticides,” which was the first report in the series and was based on early results from 1992 to 1995. About 1 billion pounds of conventional pesticides are used each year in the United States to control weeds, insects, and other pests. The use of pesticides has resulted in a range of benefits, including increased food production and reduction of insect-borne disease, but also raises questions about possible adverse effects on the environment, including water quality. The NAWQA assessment of pesticides provides the most comprehensive national-scale analysis to date of pesticide occurrence and concentrations in streams and ground water. NAWQA results show where, when, and why specific pesticides occur in streams and ground water across the Nation, and yield science-based implications for assessing and managing the quality of our water resources.