Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA

Hydrogeology Journal (Springer) | May 30th, 2009

Groundwater pumping has led to extensive waterlevel declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was dev

Groundwater pumping has led to extensive waterlevel declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was developed to test the hydraulic implications of a sequence-stratigraphic model of the Dominguez Gap area and to assess the effects of water-management scenarios. The model is two-dimensional, vertical and follows an approximate flow line extending fromthe Pacific Ocean through the Dominguez Gap area. Results indicate that a newly identified fault system can provide a pathway for transport of seawater and that a stratigraphic boundary located between the Bent Spring and Upper Wilmington sequences may control the vertical movement of seawater. Three 50-year water-management scenarios were considered: (1) no change in water-management practices; (2) installation of a slurry wall; and (3) raising inland water levels to 7.6m above sea level. Scenario 3 was the most effective by reversing seawater intrusion. The effects of an instantaneous 1-m sealevel rise were also tested using water-management scenarios 1 and 3. Results from two 100-year simulations indicate that a 1-m sea-level rise may accelerate seawater intrusion for scenario 1; however, scenario 3 remains effective for controlling seawater intrusion.

Sustainable L.A. Grand Challenge Environmental Report Card for Los Angeles County: Water 2019

University of California, Los Angeles (UCLA) | October 22nd, 2019

The Sustainable LA Grand Challenge (SLA GC) Environmental Report Card (ERC) for Los Angeles County (L.A. County) is the only comprehensive environmental report card for

The Sustainable LA Grand Challenge (SLA GC) Environmental Report Card (ERC) for Los Angeles County (L.A. County) is the only comprehensive environmental report card for a megacity in the world. This 2019 ERC on Water provides an in-depth look at the region’s efforts in moving toward a more resilient local water supply, which requires maximizing high quality local water supplies, improving water conveyance and treatment infrastructure, reducing water consumption, and implementing innovative technology and policy solutions. Twenty indicators were assessed across eight categories. Many of these indicators are new areas of assessment for the ERC and will provide a more comprehensive picture of current conditions compared to the 2015 ERC that last assessed L.A. County’s water. Grades were assigned in each category based on compliance with environmental laws or numeric standards where applicable, on our best professional judgment, and on historical improvements and context. This year’s grades range from D/ Incomplete to B+, and although there has been great progress in some areas, others still require significant improvement to raise the county’s C+ average.

Systems Analysis and Optimization of Local Water Supplies in Los Angeles

American Society of Civil Engineers (ASCE) | September 1st, 2017

Los Angeles, which relies on large infrastructure systems that import water over hundreds of miles, faces a future of reduced imports. Within Los Angeles and its hund

Los Angeles, which relies on large infrastructure systems that import water over hundreds of miles, faces a future of reduced imports. Within Los Angeles and its hundreds of water agencies, the capacity to adapt to future changes is influenced by laws, institutions, and hydrogeology. This paper presents a systems analysis of urban water management in metropolitan Los Angeles County to assess opportunities for increasing local water reliance. A network flow model was developed to investigate management tradeoffs across engineered, social, and environmental systems. With an aggressive regional demand target, increased stormwater capture (300%), and prioritized water reuse from existing facilities, imported water supplies can be cut by 30% while maintaining landscapes, economic productivity, and groundwater resources. Further reducing imports (by 40–50%) is possible through actions to promote additional reuse, recharge, conservation, and groundwater access. Reducing imported water without significant conservation results in likely groundwater overdraft. Fragmented networks of agencies in Los Angeles create an uneven landscape of vulnerability to water shortages. The paper discusses model applications, research needs, and policy implications of results for dry-climate cities.

Testimony of Mark Cowin at Little Hoover Commission on Integrated Regional Water Management

Little Hoover Commission | September 24th, 2009

As the Little Hoover Commission evaluates California’s water governance structure and forms recommendations for improving coordination, efficiency, transparency, and ac

As the Little Hoover Commission evaluates California’s water governance structure and forms recommendations for improving coordination, efficiency, transparency, and accountability, it will be valuable to consider the role of Integrated Regional Water Management (IRWM). IRWM is the application of broader Integrated Water Management principles on a regional basis. IRWM integrates local agency responses to regional resource management issues and facilitates compliance with State laws and policies. Over the past decade, IRWM efforts have emerged across California as some local governments and agencies sought a path forward from long, debilitating law suits and many others responded to financial incentives offered by the State. As a consequence, many local governments and agencies are working more closely on a regional basis and better integrating their resource management decisions. This typically results in both more efficient and sustainable water management plans and better representation and transparency in water management decisions.

The Anatomy of a Drought in the Upper San Francisco Estuary: Water Quality and Lower-Trophic Responses to Multi-Year Droughts Over a Long-Term Record (1975-2021)

University of California, Davis (UC Davis) | December 23rd, 2024

The Climate has Changed: Now what? Integrated Regional Water Management and Climate Change Planning A Coincidental or Inevitable Union?

California Department of Water Resources (DWR) | March 27th, 2012

Adapting California’s water management systems in response to climate   change presents one of the most significant challenges for the 21st century. In the course of

Adapting California’s water management systems in response to climate   change presents one of the most significant challenges for the 21st century. In the course of the past five years, the California Department of Water Resources has taken an active role in both identifying opportunities to mitigate greenhouse gas (GHG) emissions and in positioning California to adapt to changes happening now and in the future. The recent publication of the Climate Change Handbook for Regional Water Planning is the most recent effort to bring together two separate water planning efforts – integrated regional water management and climate change mitigation and adaptation. The key to this planning synthesis is a significant change in the way water planners have addressed issues of water management. This paper looks at the development of integrated regional water management and climate change planning by the CDWR and their current union in the Handbook.

The economic value of local water supplies in Los Angeles

Nature Portfolio (Springer Nature) | May 21st, 2018

Los Angeles imports water over long distances to supplement local supplies. Reduced reliability of the available imports is driving many local agencies to promote conserv

Los Angeles imports water over long distances to supplement local supplies. Reduced reliability of the available imports is driving many local agencies to promote conservation and enhance local water sources. These include stormwater capture, water reuse and groundwater. But financial considerations are often a significant impediment to project development, especially when comparing new and existing sources. Here we demonstrate a comprehensive approach for evaluating the economic implications of shifting to local water reliance in Los Angeles County. We show that local water supplies are economically competitive. Results from integrated hydroeconomic modelling of urban water in Los Angeles identify cost-effective water supply portfolios and conservation targets. Considering costs across the ‘full-cycles’ of urban water supply that span agency boundaries yields better comparisons of planning alternatives. Throughout the region, many water retailers could successfully mitigate effects of imported water cuts while still supporting drought-tolerant landscapes, but some would suffer due to over-reliance on imports. Updating economic assessment methods would support needed innovations to achieve local reliance in Los Angeles, including infrastructure investments, institutional reforms, many more drought-tolerant landscapes and reallocated groundwater rights.

The Economic Value of Nature's Services and its role in Integrated Water Management: Four California Case Studies

California Department of Water Resources (DWR) | July 1st, 2014

Here we present four case studies of integrated regional water management that include enhancement of biological diversity among their goals. Each pilot-scale project foc

Here we present four case studies of integrated regional water management that include enhancement of biological diversity among their goals. Each pilot-scale project focuses on multiple water-related natural resources in a defined geographic area, usually a watershed. A common element of the projects is to show the economic benefits of protecting and restoring natural resources in a manner that allows their continued use over the long term. One of the aims of the projects is to recognize the economic value of the goods and services that nature provides and to incorporate that value into natural resource management decisions. Such recognition includes development of ways to measure the economic value of those services. This can be important information for water managers who normally see only the costs of ecosystem protection and restoration, but not the benefits, in their budgets. The goods and services considered in these projects include water supply, water quality, erosion prevention, wildfire prevention, hydropower generation, wood products, flood attenuation, carbon sequestration, land subsidence reversal, and fish and wildlife. Collectively, the projects constitute on-the-ground efforts to advance several of the objectives in the implementation plan of Water Plan 2009. In particular, they aim to expand integrated regional water management (objective 1), protect surface water and groundwater quality (objective 4), expand environmental stewardship (objective 5), practice integrated flood management (objective 6) and manage a sustainable California Delta (objective 7). The case studies accomplish and document several key ingredients of integrated resource management--although no single study does all of them. They identify and involve watershed stakeholders, both managers and users of natural resources. In turn, the stakeholders come to agreement about how they want the watershed to look or function, usually in terms of the goods and services that they want the watershed to provide. Then they reach agreement on a set of management practices that can support and enhance those services and move the watershed toward the desired condition. Finally, the case studies seek to estimate the amounts of goods and services derived from specific management practices. The pilot projects go beyond most watershed management efforts and most ecosystem services work in laying the foundation for establishment of markets for nature’s services, that is, mechanisms for beneficiaries to pay producers for goods and services they receive. This requires some sort of assessment of the monetary value of the benefits. One desired end product is to put payments in the hands of producers-- that is, resource managers—as an incentive to keep them producing.

The Evolution of Metropolitan’s Agricultural Partnerships

Metropolitan Water District of Southern California (MWD) | August 5th, 2022

The Future of Groundwater in California: Lessons in Sustainable Management from Across the West

Environmental Defense Fund (EDF) | January 31st, 2018

The 2014 Sustainable Groundwater Management Act (SGMA) created, for the first time and on an unprecedented scale, a mandate to change how groundwater is managed statewide

The 2014 Sustainable Groundwater Management Act (SGMA) created, for the first time and on an unprecedented scale, a mandate to change how groundwater is managed statewide in California. While enacting SGMA was a tremendous step forward, communities and water districts now face the considerable challenge of creating successful groundwater management programs. This report is aimed at helping California’s water managers, public water agencies, county commissioners, city planners, and others better understand the suite of tools and approaches that can be used to enhance the sustainable management of groundwater. Specifically, we consider four categories of management tools—regulatory, incentive-based, agency supply augmentation and protection, and education and outreach—to evaluate how these tools are being used to address water quantity, water quality, and surface water and groundwater interaction challenges. We present nine comprehensive case studies of groundwater management across the Western United States to highlight how these tools have been used to address those challenges. The case studies represent basins that have a range of water uses— agricultural, municipal, or mixed water use, as well as basins with diverse hydrologic, political and social settings. Effective groundwater management takes time and requires significant resources and commitment on the part of water managers and communities. Each groundwater management program presented in this report relies upon a variety of interdependent tools and actions to meet management goals. The case studies illustrate the importance of building trust, having sufficient data, using a portfolio of management approaches, assuring performance, and access to funding. Given the similarities between the goals of SGMA and those described in the case studies, these themes emerge as crucial to the successful implementation of California’s landmark groundwater legislation.