Physical water system consolidation alone cannot resolve drinking water failure in California’s San Joaquin Valley

Nature Portfolio (Springer Nature) | July 2nd, 2026

Small community water systems in California’s San Joaquin Valley disproportionately fail to provide safe drinking water, with most serving disadvantaged communities and

Small community water systems in California’s San Joaquin Valley disproportionately fail to provide safe drinking water, with most serving disadvantaged communities and lacking the technical, managerial, and financial capacity to maintain compliance. The State Water Board designates such systems as failing when they have documented violations of drinking water standards or cannot reliably deliver safe water. Physical consolidation, which involves connecting a smaller failing system to a larger provider through new pipeline infrastructure, is the primary long-term solution promoted by state regulators. Here, we assess consolidation feasibility and capital costs across four counties (Kern, Kings, Tulare, and Fresno) via the state’s 2024 screening methodology. The methodology identifies smaller failing and at-risk systems as candidates for joining a larger receiving system with sufficient capacity. Among the 210 eligible systems, 114 (54%) matched a receiving system within three miles, with an estimated total capital need of $413.5 million. Nearly all identified pairs met state funding viability thresholds. The remaining 96 systems, including 49 classified as failing, lacked an eligible receiving partner and will require alternative solutions. Physical consolidation is necessary but insufficient for achieving safe drinking water access across the region.

Pilot Projects to Increase Colorado River System Water in Lake Powell and Lake Mead

U.S. Bureau of Reclamation (USBR) | January 14th, 2022

From calendar year 2015 through 2018, 64 projects were implemented in the Upper Basin resulting in an estimated 47,280 acre-feet of Colorado River System water conserved

From calendar year 2015 through 2018, 64 projects were implemented in the Upper Basin resulting in an estimated 47,280 acre-feet of Colorado River System water conserved in the Upper Basin at a cost of $8.5 million or $180.23 per acre-foot on average. From January 2015 through December 31, 2019 in the Lower Basin, 16 projects were implemented which will result in 175,347 acre-feet of Colorado River System water in Lake Mead by 2035, at a cost of approximately $29.8 million or $170.14 per acre-foot on average. The Pilot Program successfully demonstrated that voluntary, compensated water conservation projects can conserve water for Colorado River System storage to help mitigate the impacts of drought.

Piru Basin Groundwater Sustainability Plan

Fillmore and Piru Basins Groundwater Sustainability Agency | December 16th, 2021

The Piru Basin (the Basin) is managed (along with the downslope Fillmore Basin) by the Fillmore and Piru Basins Groundwater Sustainability Agency (Agency). The Basin is p

The Piru Basin (the Basin) is managed (along with the downslope Fillmore Basin) by the Fillmore and Piru Basins Groundwater Sustainability Agency (Agency). The Basin is planned to remain sustainable over the Sustainable Groundwater Management Act (SGMA) implementation and sustainability period, based on the current understanding of historical, current (2019), and projected (2022 through 2072) groundwater conditions in relation to the sustainability indicators specified in SGMA. A sustainability indicator refers to any of the effects caused by groundwater conditions occurring throughout the basin that, when significant and unreasonable, cause undesirable results. The Agency, with consideration of feedback from active stakeholder engagement, has identified and planned for the prevention of significant and unreasonable undesirable results.

Piru Basin Groundwater Sustainability Plan Final (Revised)

Fillmore and Piru Basins Groundwater Sustainability Agency | July 8th, 2024

Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11, Part 12, Part 13

Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11, Part 12, Part 13

Pixley Irrigation District Groundwater Sustainability Plan

Pixley Irrigation District Groundwater Sustainability Agency (PIDGSA) | January 21st, 2020

Pixley Irrigation District Groundwater Sustainability Plan (Revised)

Pixley Irrigation District Groundwater Sustainability Agency (PIDGSA) | July 27th, 2022

The Tule Subbasin is designated by DWR as a critically overdrafted basin with an estimated subbasin average overdraft of 115,300 acre-feet per year. The Agencies estimat

The Tule Subbasin is designated by DWR as a critically overdrafted basin with an estimated subbasin average overdraft of 115,300 acre-feet per year. The Agencies estimated annual average overdraft within the Tule Subbasin is 70,000 acre-feet per year. The overdraft conditions have caused issues for those reliant on groundwater pumping, which include municipal, domestic, and agriculture users. Other issues generated from the overdraft include areas of land subsidence, which predominantly occur in the northwestern portion of the Agency. A sample of the Pixley GSP is displayed below. Due to size, this full 2,421-page document must be downloaded from the Department of Water Resources.

Plan of Development Sacramento-San Joaquin Delta

Interagency Delta Committee (IDC) | January 20th, 1965

Plan writing as a policy tool: instrumental, conceptual, and tactical uses of water management plans in California

Journal of Environmental Studies and Sciences (Springer) | February 24th, 2022

Numerous environmental regulations require organizations to codify prospective activities in a written plan. However, evidence suggests that many plans are never implemen

Numerous environmental regulations require organizations to codify prospective activities in a written plan. However, evidence suggests that many plans are never implemented, raising questions about why public agencies continually require plans, whether mandating plans allows agencies to meet their policy aims, and what additional purposes plans serve. Adopting concepts from literature on research utilization, we develop a plan use typology, defining instrumental use as occurring when the requirement to write a plan directly addresses a stated policy problem, conceptual use as occurring when the requirement to write a plan indirectly addresses a policy problem by raising awareness of an issue or improving governance capacity, and tactical use as occurring when the requirement to write a plan serves a political or symbolic purpose unrelated to solving the policy problem. We then apply the typology to four California statutes that require local and regional utilities to write water management plans. We first assess the statutes to identify the goals underlying the requirement to write a plan and assess what plan uses are emphasized in guidance documents and the written plans themselves. Lastly, we interview the plan writing organizations to capture their perspectives on the value and limitations of these plans. We find that legislators turn to plans to support instrumental and conceptual goals but that the plans themselves and the way they are used by authoring agencies primarily serve conceptual and tactical uses, suggesting a disconnect between the policy goals underlying plans and their actual use.

Planned operation of large-scale water-distribution system

American Society of Civil Engineers (ASCE) | May 1st, 1995

A water-supply-distribution-system planning model has been developed using a directed graph algorithm as its pre- and post-processors and a linear programming (LP) proced

A water-supply-distribution-system planning model has been developed using a directed graph algorithm as its pre- and post-processors and a linear programming (LP) procedure as an “intelligent” system operator at its core. The directed graph, as a preprocessor, is used to produce a mathematical representation of the distribution system in question, to check the consistency and correctness of the network topology before an input file is created for the LP procedure. In the postprocessing mode, the directed graph generates files for graphical displays of model results and performs graph analyses such as depth- and breadth-first traversals, cut-set and connectivity for evaluating water-quality blending, tracking of source-to-demand contributions, system reliability, and lifeline objectives. Unlike the conventional formulation of a resource-allocation problem, the demand requirements, storage capacities, and other system constraints are removed from the constraint set and translated into a composite objective function. This methodology was successfully applied to the Metropolitan Water District of Southern California's (MWD's) distribution system. The results indicate that the combination of using an LP procedure and graph algorithm is a very versatile tool for solving large-scale water-distribution problems. This paper documents the concept used in developing the system-planning model and the results of its application to a simplified example as well as application to four case studies involving the entire MWD's distribution system.

Planning and investing for a resilient California: A guidebook for state agencies

Governor's Office of Planning and Research (OPR) | November 17th, 2017

Executive Order (EO) B-30-15 (April 2015; Appendix A) identified three actions to advance adaptation and resilience: 1. Preparation of Implementation Action Plans to id

Executive Order (EO) B-30-15 (April 2015; Appendix A) identified three actions to advance adaptation and resilience: 1. Preparation of Implementation Action Plans to identify the steps that will be taken to realize the goals in Safeguarding California; 2. Direction to all State agencies to consider climate change in all planning and investment, including infrastructure investment; and 3. Direction to the Governor’s Office of Planning and Research (OPR) to establish a Technical Advisory Group (TAG) to provide state agencies with guidance on how to integrate climate change into planning and investment. This document is the product of the Technical Advisory Group (TAG) formed under EO B-30-15. The TAG was comprised of representatives from a majority of agencies, departments, offices and commissions of the Governor’s executive branch, and members of the public, including local and regional governments, non-governmental organizations, and the private sector (see Appendix B). This guidance document is designed to inform planning and investment processes to address the two primary elements of resilience – planning for future conditions and doing planning itself differently. This document introduces a four step process and a set of resilient decision making principles for state agencies.