USGS Report: Increased Pumping in California’s Central Valley During Drought Worsens Groundwater Quality

From the USGS:

Intensive pumping of aquifers during drought can speed up deterioration of groundwater quality, according to a new study by the U.S. Geological Survey. The results highlight clean drinking water supply vulnerabilities in California and other western states currently experiencing record drought conditions.

polluted groundwater

Over-pumping during drought can increase nitrate at public-supply wells.

“Water quality problems from legacy groundwater pollution could get worse, faster, when pumping increases during drought,” said Dr. Zeno Levy, a research geologist with the USGS. “This could lead to more public drinking-water wells being shut down if costly treatment or cleaner water sources to mix with are not available.”

Researchers examined 30 years of data from California’s Central Valley to find increasing nitrate concentrations at public drinking-water wells were more prevalent in areas where groundwater levels dropped rapidly during drought. Nitrate is a contaminant from fertilizer typically present at elevated concentrations in shallow groundwater throughout the Central Valley due to decades of agricultural land use. Scientists found that increased pumping from wells during drought can pull shallow, contaminated groundwater down to depths commonly tapped for public drinking-water supply.

Previous groundwater research has focused on the risk of wells being overdrawn and running dry during drought. The new study provides a major advancement to understanding the related consequences to water quality caused by over pumping.

The study is unique in that it looked at regional linkages between groundwater use and quality, rather than local patterns at the scale of individual wells. This research was undertaken as part of a cooperative effort between the USGS and the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment Program.

The study “Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought” is published in Geophysical Research Letters.

REPORT: At Risk: Public Supply Well Vulnerability Under California’s Sustainable Groundwater Management Act

“California’s Sustainable Groundwater Management Act was designed to prevent significant and unreasonable chronic lowering of groundwater levels across the state, among other undesirable effects. Yet implementation often does not protect shallow wells.  This report examines public drinking water supply well vulnerability under the Sustainable Groundwater Management Act. It focuses on wells and water systems in the San Joaquin Valley due to the area’s social and economic significance, high concentration of water-related challenges, and availability of developed groundwater sustainability plans. 

The report finds that 503 of the 1,200 public supply wells in the region, or 42%, are likely to be partially or fully dry at the minimum thresholds established in the region’s sustainability plans. It includes recommendations to support small water systems and domestic wells and improve the resilience of groundwater sustainability Plans, in line with the state’s Human Right to Water.  ... ”

Click here to read this report from Pacific Institute.

Click here to visit the Groundwater Exchange’s news page.

Mitigating Domestic Well Failure for SGMA and Drought in the San Joaquin Valley

“Domestic wells serve sizable potable water demands in California and much of the world. These wells tend to degrade and fail with declining regional groundwater levels. In areas of irrigated agriculture, impacts to shallower domestic wells may occur from ongoing groundwater use and worsen during drought when agricultural pumping increases to compensate for diminished surface water supplies. Impacts on domestic wells include increased pumping lift, pump cavitation, well screen clogging, and wells running dry.

Our recent work examines the potential for managing these impacts in part of the San Joaquin Valley where groundwater sustainability plans were completed in 2020 as required by the Sustainable Groundwater Management Act. …

Click here to continue reading at the California Water Blog.

Click here to visit the Groundwater Exchange’s news page.

REPORT: Dispute Resolution Clauses In Interorganizational Coordination Agreements: A Comparative Analysis

Adoption of California’s Sustainable Groundwater Management Act (SGMA) in 2014 posed a major coordination challenge for diverse public agencies by requiring them to align their activities at the scale of groundwater basins, which is not how most governing bodies are organized. Meeting this requirement meant establishing governing and operating relationships between agencies. Such interorganizational relationships (IORs) are essential in many fields, but are also prone to conflict. Understanding the factors affecting the inclusion, specificity and salience of dispute resolution clauses (DRCs) in interorganizational agreements ensures the long-term functionality of IORs.

We examined 74 multi-entity agreements forming new quasi-voluntary local agencies, devoted to developing and implementing groundwater sustainability plans to achieve groundwater sustainability under SGMA.  Statistical analyses were performed to identify potential factors influencing both the inclusion of DRCs in agreements, as well as the degree of specificity. Agency annual operating budgets and the use of facilitation services during agreement formation were statistically significant factors in predicting the inclusion of DRCs in agreements. Interviews were conducted with a subset of agency representatives, facilitators and lawyers to understand factors motivating the inclusion of DRCs and the salience of those clauses.

We found a near uniform lack of salience associated with the DRCs. While DRCs are considered an important component of multientity agreements, their inclusion and specificity are often driven by agreement drafters with minimal involvement of agreement parties impacting the salience of DRCs and potentially their use long-term.

Click here to read this report from Stanford’s Water in the West.

Click here to visit the Groundwater Exchange’s news page.

Analysis of 31 GSPs in Critically Overdrafted Basins

One of the key criteria that the Department of Water Resources (DWR) must consider when evaluating whether a GSP is likely to achieve the sustainability goal for the basin is “Whether the interests of the beneficial uses and users of groundwater in the basin, and the land uses and property interests potentially affected by the use of groundwater in the basin, have been considered” (23 California Code of Regulations [CCR] § 355.4(b)(4)).

In regard to this and other statutory requirements to consider and address the needs of all beneficial users in GSPs, a group of NGOs, with the support of Water Foundation, collectively reviewed 31 GSPs in 16 critically overdrafted basins and subbasins.

The organizations collectively submitted detailed formal comment letters to each GSA on the public draft GSPs as well as detailed formal comment letters to DWR on the final GSP documents, within the formal public review period.

The reviews were prioritized towards those GSPs that were considered to be of high priority by our organizations due to the presence of: (1) small drinking water systems, (2) groundwater dependent ecosystems (GDEs), and (3) DACs. Prioritization also considered coverage and interest by the respective organizations, with the goal of selecting at least one GSP per critically overdrafted basin.

Although we did not review all 46 submitted GSPs, the findings from our analysis are both valuable to inform GSP implementation and updates in critically overdrafted basins, and to inform the development and review of GSPs currently being drafted for the remaining high- and medium-priority basins. For each of the five key elements, the following sections discuss: (1) the regulatory basis for consideration of beneficial users, (2) a summary of our review findings, (3) a discussion of how the GSPs should have more adequately addressed the key issues, and (4) a selection of “Model GSP Elements” from reviewed GSPs.

It is the goal of this analysis to share our findings in order to help inform and improve the development of GSPs for non-critically overdrafted basins, as well as to inform opportunities for improvement of GSPs for critically overdrafted basins.

For more analysis on the 2020 GSPs, visit the 2020 GSP page at the Groundwater Exchange.

New report identifies major gaps in SGMA, provides recommendations

In 2014, California’s landmark Sustainable Groundwater Management Act (SGMA) promised comprehensive management of California’s groundwater. The report, based on joint analysis by Stanford University’s Water in the West and The Nature Conservancy, finds that SGMA actually suffers from several major gaps in its coverage.

Indeed, SGMA currently protects less than two percent of California’s groundwater. While SGMA covers those groundwater basins where the vast majority of pumping today occurs, it does not protect many other important groundwater sources, leaving that groundwater at risk of over-pumping, now and in the future, with no state oversight to safeguard rural domestic wells, sensitive habitats, and other beneficial uses of water. 

This report, Mind the Gaps: The Case for Truly Comprehensive Sustainable Groundwater Management, details SGMA’s gaps and their consequences and recommends several ways to remedy these gaps. The gaps largely stem from the ways in which the California Department of Water Resources (DWR) defines and prioritizes groundwater basins in Bulletin 118 (California’s Groundwater). … ”

Read the report here: Mind the Gaps: The Case for Truly Comprehensive Sustainable Groundwater Management

Report provides guidance on repurposing California farmland to benefit water, landowners, communities and wildlife

Over the coming decades, California’s San Joaquin Valley will transition to sustainable groundwater management under the Sustainable Groundwater Management Act (SGMA), ensuring reliable groundwater supplies for generations to come. Sustainable groundwater management and a changing climate will inevitably affect how land is used on a sweeping scale. …

To help groundwater sustainability agencies (GSAs), local governments, rural communities and land use planners facing these challenges, Environmental Defense Fund worked with a broad group of stakeholders to develop a new guide, Advancing Strategic Land Repurposing and Groundwater Sustainability in California. …

Read more from the Environmental Defense Fund here:  Report provides guidance on repurposing California farmland to benefit water, landowners, communities and wildlife

California regions submitted their first Groundwater Sustainability Plans in 2020. How did they do?

” … With support from the Water Foundation, a collaborative effort among California nonprofits and community groups has been leading statewide advocacy to ensure public agencies and elected officials implement the legislation fairly, effectively, and equitably.

This month, the group marked an important milestone.  Over the past year, researchers and advocates at Ag Innovations, Audubon California, Clean Water Fund, Local Government Commission, The Nature Conservancy, and Union of Concerned Scientists, among others, have been pouring over thousands upon thousands of pages of local groundwater sustainability plans.  While often hard to decipher and full of technical jargon, these plans reveal more about California’s groundwater health than we’ve ever seen publicly available before. …

Continue reading at the Water Foundation here:  California Regions Submitted Their First Groundwater Sustainability Plans in 2020. How Did They Do?

The Basin Characterization Model—A Regional Water Balance Software Package

This report documents the computer software package, Basin Characterization Model, version 8 (BCMv8)—a monthly, gridded, regional water-balance model—and provides detailed operational instructions and example applications. After several years of many applications and uses of a previous version, CA-BCM, published in 2014, the BCMv8 was refined to improve the accuracy of the water-balance components, particularly the recharge estimate, which is the most difficult to accurately assess.

The improvement of the various water-balance components targeted the actual evapotranspiration component, which, in turn, reduced the uncertainty of the recharge estimate. The improvement of this component was enabled by the availability of a national, gridded actual-evapotranspiration product from the U.S. Geological Survey that was unique in its scope to combine remotely sensed spatial variability and ground-based long-term water-balance constraints.

This dataset provided the ability to assess monthly actual evapotranspiration for 62 vegetation types and to perform regional calibration in watersheds throughout California with the objective of closing the water balance using improved estimates for each component. The refinements, including vegetation-specific evapotranspiration, enabled the development of applications that could explore various aspects of landscape disturbance, such as wildfire, forest management, or urbanization.

The improvements to BCMv8 also provided the ability to assess long-term sustainability of water resources under a variety of management applications or future climate projections.

For more information, click here.

Research Briefs: CA Farmer Perspectives on Groundwater Management

From the Water Foundation:

Producing food requires large water resources, and in California, thousands of farms are mostly or solely reliant on groundwater sources. While farmers are integral stakeholders in sustainable groundwater management, the perceptions of individual farmers regarding water policy and management are not well understood.

Food system and natural resources researchers at the University of Vermont surveyed Yolo County farmers in 2017 to understand their perspectives on SGMA, water management practices, and policy preferences. In 2019, with support from the Water Foundation, Meredith Niles at the University of Vermont and Courtney Hammond Wagner at Stanford University expanded their survey and analysis to farmers in Fresno, Madera, and San Luis Obispo counties, in partnership with local county farm bureaus.

Together, these four county-level surveys of 690 farmers revealed many similarities in farmers’ perspectives, despite agricultural and sociocultural differences. …

Click here to continue reading at the Water Foundation.

See also: To Achieve Sustainable Groundwater Management, CA Needs a Bigger, Inclusive Table, commentary by Alesandra Nájera and Mike Myatt