Los Angeles Basin Stormwater Conservation Study: Plan of Study

U.S. Bureau of Reclamation (USBR) | February 28th, 2013

Imported water supplies to Los Angeles County, California, are uncertain due to periodic droughts in northern California and the Colorado River Basin, court decisions r

Imported water supplies to Los Angeles County, California, are uncertain due to periodic droughts in northern California and the Colorado River Basin, court decisions related to endangered species in the Bay Delta, and potential allocations of Colorado River water. Changing demographics, climate variability, and the competing interest for available water present additional long-term risks to the stability and reliability of imported water. Accordingly, various Los Angeles area agencies with water management authority, such as the Los Angeles County Flood Control District (LACFCD), are actively pursuing a strategy aimed at achieving water independence by developing local water resources such as stormwater. The LACFCD is the primary agency for conducting groundwater replenishment operations in Los Angeles County. In typical years, the LACFCD infiltrates more than 270,000 acre-feet of captured stormwater, imported water, and recycled water into the various groundwater basins in Los Angeles County. In wetter years, that number can exceed 700,000 acre-feet and, in drier years, may be little more than 150,000 acre-feet. LACFCD partnered with the U.S. Department of the Interior, Bureau of Reclamation’s (Reclamation) Southern California Area Office to study long-term flood control and water conservation impacts from projected population and climate conditions. The Los Angeles Basin Stormwater Conservation Study (Basin Study) will recommend potential changes to the operation of stormwater capture systems, modifications to existing facilities, and development of new facilities that could help resolve future flood control and water supply issues. The Los Angeles River, San Gabriel River, Ballona Creek, South Santa Monica Bay, North Santa Monica Bay, and Dominguez Channel/Los Angeles Harbor watersheds (Watersheds) are the focus of this Basin Study (figure 1). This study incorporates the entire watershed boundaries, including where they extend outside Los Angeles County. The Watersheds share attributes such as overlapping municipal and water agency boundaries, an interconnected flood control system, and a common planning purpose with major ongoing planning efforts like the Greater Los Angeles County Integrated Regional Water Management Plan (IRWMP), Gateway IRWMP and the Metropolitan Water District Integrated Resources Plan. Related links: Los Angeles Basin Study Summary Report Task 2: Water Supply and Demand Analysis Click here for Reclamation's index of inter-related LA Basin Study reports and appendices.

Los Angeles Basin Stormwater Conservation Study: Task 3.2 Hydrologic Modeling Report

U.S. Bureau of Reclamation (USBR) | December 3rd, 2013

The Los Angeles County Flood Control District (LACFCD) partnered with the U.S. Department of the Interior, Bureau of Reclamation (Reclamation) to collaborate on t

The Los Angeles County Flood Control District (LACFCD) partnered with the U.S. Department of the Interior, Bureau of Reclamation (Reclamation) to collaborate on the Los Angeles Basin Stormwater Conservation Study (LA Basin Study). The purpose of the LA Basin Study is to investigate long-range water conservation and flood control impacts caused by projected changes in climate conditions and population in the Los Angeles region. The LA Basin Study will recommend potential modifications or changes in the operation of the existing stormwater capture systems, and the development of new facilities that could help resolve future water supply and flood control issues. These recommendations will be developed by identifying alternatives and conducting trade-off analyses. For Task 3, Downscaled Climate Change and Hydrologic Modeling of the LA Basin Study, Reclamation developed downscaled climate change projections, while LACFCD applied these projections to generate the future hydrology. LACFCD utilized the Watershed Management Modeling System (WMMS) to perform the hydrologic modeling for the LA Basin Study. This report summarizes the data, methods, and results of the historic and future hydrologic modeling. The purpose of Task 3.2, Hydrologic Modeling is to simulate hydrology with respect to climate change for the Los Angeles River, San Gabriel River, Ballona Creek, South Santa Monica Bay, North Santa Monica Bay, Malibu Creek, and Dominguez Channel/Los Angeles Harbor watersheds (Basin Study Watersheds). This study incorporates the entire watershed boundaries, including where they extend outside of Los Angeles County. The following sub-tasks were identified to achieve this objective: Historic Hydrologic Modeling (Water Year 1987 through 2000) Determine baseline scenario modeling assumptions Prepare WMMS to simulate baseline scenario Perform WMMS baseline simulations Analyze and summarize WMMS results Projected Hydrologic Modeling (Water Year 2012 through 2095) Determine future scenario modeling assumptions Prepare WMMS to simulate future scenarios Perform WMMS simulations Analyze and summarize WMMS results

Los Angeles Basin Stormwater Conservation Study: Task 5 Infrastructure & Operations Concepts Report

U.S. Bureau of Reclamation (USBR) | December 1st, 2015

The Los Angeles Basin Stormwater Conservation Study (LA Basin Study) is a collaborative partnership between the Los Angeles County Flood Control District (LACFCD) and the

The Los Angeles Basin Stormwater Conservation Study (LA Basin Study) is a collaborative partnership between the Los Angeles County Flood Control District (LACFCD) and the U.S. Department of the Interior, Bureau of Reclamation (Reclamation). The purpose of the LA Basin Study is to investigate long-range water conservation and flood risk management impacts caused by projected changes in the climate and population in the Los Angeles region. The LA Basin Study provides recommendations for potential modifications and changes to the existing regional stormwater capture system, as well as for the development of new facilities and practices, which could help to resolve future water supply and flood risk management issues. The stormwater capture concepts and alternatives developed within this report will inform the Task 6 – Trade-Off Analysis & Opportunities report of the LA Basin Study.  The objective of Task 5, Infrastructure and Operations Concepts, is to identify and develop both structural and nonstructural (i.e., plans and policies) concepts to manage stormwater under projected climate conditions for the Los Angeles Basin watersheds, which include: Los Angeles River, San Gabriel River, South Santa Monica Bay, North Santa Monica Bay, Ballona Creek, Malibu Creek, and Dominguez Channel/Los Angeles Harbor watersheds (Basin Study Watersheds). The efforts and results previously completed for Task 2 – Water Supply & Water Demand Projections, Task 3 – Downscaled Climate Change & Hydrologic Modeling, and Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis serve as the foundation for Task 5. The major tasks and subtasks of Task 5 include:  Concept Development  - Identify a range of opportunities and options using stakeholder input  - Determine preliminary concepts for further evaluation  Technical Analysis of Concepts  - Assess structural and nonstructural concepts pertaining to dams, spreading grounds, flood control channels, decentralized storage, infiltration, reuse facilities, debris basins, and other concepts  - Develop and apply concept selection criteria  Appraisal-Level Analysis  - Evaluate selected concepts for future system reliability, efficiency, and effectiveness  In addition to any new stormwater conservation concepts that are developed, the existing facilities from the Task 4 analysis were considered for enhancement. The Watershed Management Modeling System (WMMS), which has served as the primary hydrologic model throughout the LA Basin Study, continued to be the preferred tool and was also used for Task 5. Hydrologic simulations were conducted to analyze the potential water conservation and flood risk mitigation benefit for the various project concepts. For the future period, water years 2012 through 2095, four climate projections (Low 1, Low 2, Mid 2, and High 1) from Task 4 were used in the simulations.  Click here for USBR's Task 5 Appendices index: Appendix A - Infrastructure and Operations Concepts (Excel) Appendix B - Local Stormwater Capture (PDF)  Appendix C - Modeling Approach and Solutions (PDF) Appendix D - Local Management Cost (Excel) Appendix D - Regional 1 Cost (Excel) Appendix D - Regional 2 Cost (Excel) Appendix D - Regional 3 Cost (Excel) Appendix D - Storage 3 Cost (Excel) Appendix E - LACFCD Dam Hydrology and Cost Estimates (PDF)

Los Angeles Basin Study The Future of Stormwater Conservation: Task 6 – Trade-Off Analysis & Opportunities

U.S. Bureau of Reclamation (USBR) | January 5th, 2016

The Los Angeles Basin Study (LA Basin Study) is a collaborative partnership between the Los Angeles County Flood Control District (LACFCD) and the U.S. Department of the

The Los Angeles Basin Study (LA Basin Study) is a collaborative partnership between the Los Angeles County Flood Control District (LACFCD) and the U.S. Department of the Interior, Bureau of Reclamation (Reclamation). The purpose of the LA Basin Study is to investigate long-range water conservation and flood risk impacts caused by projected changes in climate and population in the Los Angeles region. The LA Basin Study highlights opportunities for potential modifications and changes to both the existing regional stormwater capture system as well as for the development of new facilities and practices, which could help to resolve future water supply and flood risk issues. The stormwater capture concepts and alternatives developed in the Task 5 – Infrastructure & Operations Concepts report are evaluated in the trade-off analysis and opportunities highlighted in this report.  The primary purpose of Task 6 – Trade-Off Analysis & Opportunities is to evaluate the quantifiable and non-quantifiable benefits and costs of the stormwater concepts identified in the Task 5 report and to provide an analysis of the trade-offs among concepts. In most cases, various project concepts would generate benefits for some impact categories but not others, and would also impose various types of costs. The trade-off analysis provides a methodology for comparing different types of benefits and costs that cannot all be quantified in monetary terms. These trade-offs include economic, financial, environmental, and social effects. Economic effects include the benefits associated with different types of goods and services supported by the concepts, the costs of the different concepts, the impacts of the different concepts on the regional economy through changes in the amount and type of spending, and the cost effectiveness of different project concepts. Financial effects reflect the impacts of paying for a project, such as paying off capital debt and covering operation and maintenance expenses. Environmental effects reflect the type and quality of environmental and natural resources that would be potentially influenced by a concept. Environmental effects include items such as water quality, energy consumption, impacts on habitat, and ecosystem function. Social effects reflect how the concepts may alter the social characteristics of a community or region such as impacts to education, environmental justice, and quality of life.  Benefits are quantified for three categories of resource impacts. The first category is additional stormwater conserved or stored, which is measured in terms of acre-feet per year. The second is recreation, which is measured in miles of new trails. The third is increased habitat acreage and additional acquisition of right-of-way acreage that would provide habitat benefits. Stormwater conservation benefits are valued as improved water supply reliability, recreation is valued as a type of general recreation activity similar to outdoor activities at a local park, and habitat acreage is evaluated as an ecosystem improvement. In the case of the Regional Impact Programs concept, right-of-way acreage also produces some ecosystem benefits. Quantified benefits and costs as well as categories of qualitative benefits are summarized in Table ES-1. All benefits and costs are present valued over a 50-year planning period using the current Fiscal Year 2016 federal water project planning rate of 3.125%.  The economic analysis of quantified benefits can be used to evaluate the magnitude of potential benefits of each project group, recognizing that many additional benefits may exist that are not accounted for in a traditional benefit and cost analysis. It is important to note that quantified benefits could only be developed for a subset of the total beneficial effects associated with the concepts identified in the Task 5 report. There are many potential benefits associated with environmental and social improvements, flood risk mitigation, environmental justice, and other effects that could be large but cannot be evaluated quantitatively for this level of analysis. These unquantified benefits may be larger than quantified benefits in some cases and smaller in other cases. The intent of the qualitative assessment is to provide an indication of the potential magnitude of unquantified benefits. 

Los Angeles Department of Water and Power 2016 Annual Owens Valley Report

Los Angeles Department of Water & Power (LADWP) | December 1st, 2015

This report includes Los Angeles Department of Water and Power’s (LADWP) proposed Owens Valley operations plan for the first six months of the 2016-17 runoff year, an u

This report includes Los Angeles Department of Water and Power’s (LADWP) proposed Owens Valley operations plan for the first six months of the 2016-17 runoff year, an update on Owens Valley conditions, the current status of LADWP’s environmental mitigation projects, and the status of other studies, projects, and activities.

Los Angeles Department of Water and Power 2018 Annual Owens Valley Report

Los Angeles Department of Water & Power (LADWP) | December 1st, 2017

This report includes Los Angeles Department of Water and Power’s (LADWP) proposed Owens Valley Operations Plan for the 2018-2019 Runoff Year, an update on Owens Valley

This report includes Los Angeles Department of Water and Power’s (LADWP) proposed Owens Valley Operations Plan for the 2018-2019 Runoff Year, an update on Owens Valley conditions, and the current status of LADWP’s environmental mitigation projects and other legal obligations under the Agreement between the County of Inyo and the City of Los Angeles and its Department of Water and Power on a Long-Term Groundwater Management Plan for Owens Valley and Inyo County (Water Agreement); the 1991 Environmental Impact Report Water from the Owens Valley to Supply the Second Los Angeles Aqueduct, 1970 to 1990, 1990 Onward, Pursuant to a Long Term Groundwater Management Plan (1991 EIR); the Laws Type E transfer; the 1997 Memorandum of Understanding between the City of Los Angeles Department of Water and Power, County of Inyo, the California Department of Fish and Game, the California State Lands Commission, the Sierra Club, and the Owens Valley Committee (1997 MOU), the August 2004 and March 2010 Amended Stipulations and Orders in Case No. S1CVCV01-29768.

Los Osos Community Services District v. Golden State Water Company

Superior Court of California, County of San Luis Obispo | October 14th, 2015

This Stipulated Judgment concerns the Los Osos Groundwater Basin, as it is more particularly described in Sections 1.4.2 and 2.1 of this Stipulated Judgment, which underl

This Stipulated Judgment concerns the Los Osos Groundwater Basin, as it is more particularly described in Sections 1.4.2 and 2.1 of this Stipulated Judgment, which underlies the unincorporated communities of Los Osos, Baywood Park and Cuesta-by-the-Sea in San Luis Obispo County, California (“Basin”). The Basin is the only source of water for residential, commercial, institutional and agricul-tural development on properties overlying the Basin. This litigation (the “Action”) relates to efforts by the parties to sustainably manage the water resources of the Basin and to protect and promote the economic, environmental and social health of the community.

Los Osos Valley Groundwater Basin Fringe Areas Characterization

San Luis Obispo County Flood Control and Water Conservation District | May 22nd, 2018

The Sustainable Groundwater Management Act (SGMA) took effect on January 1, 2015, and requires that certain actions be taken in groundwater basins designated as either hi

The Sustainable Groundwater Management Act (SGMA) took effect on January 1, 2015, and requires that certain actions be taken in groundwater basins designated as either high or medium priority by the California Department of Water Resources (DWR), including Los Osos Basin. DWR identified the Los Osos Basin as a high priority basin subject to critical conditions of overdraft due to seawater intrusion and nitrate impairment (DWR, 2014, 2016). SGMA does not apply to the Los Osos Basin area that is at issue in Los Osos Community Services District v. Southern California Water Company [Golden State Water Company], et al.1 (Adjudicated Plan Area), for which a Stipulated Judgment was approved in San Luis Obispo Superior Court on October 14, 2015. The boundaries of the Adjudicated Plan Area do not coincide with the Basin boundaries as documented in DWR’s Interim Update to Bulletin 118 (2016). The groundwater basin areas between the Bulletin 118 Basin boundaries (Basin 3‐8) and the Adjudicated Plan Area boundary are referred to as “Fringe Areas” (Figure 1). In order to comply with SGMA, the County of San Luis Obispo (County) formed the Groundwater Sustainability Agency (GSA) over these Fringe Areas on April 4, 2017. The results of this basin characterization study are intended to produce a basis of knowledge for use in boundary modification requests and potential future use in development of a Groundwater Sustainability Plan (GSP). Decades of technical studies on the basin have focused primarily on aquifers within the Adjudicated Plan Area. This technical memorandum supplements prior work, which together provide a comprehensive hydrogeologic characterization and conceptual model of the Fringe Areas.

Lower Mill Creek Watershed Conjunctive Use Project: Tehama County, California

California Department of Water Resources (DWR) | November 18th, 2008

In 1920, the Tehama County Superior Court of the State of California adjudicated entitlements to all Mill Creek flow below 203 cubic feet per second (cfs). As such, water

In 1920, the Tehama County Superior Court of the State of California adjudicated entitlements to all Mill Creek flow below 203 cubic feet per second (cfs). As such, water right holders on Mill Creek legally divert a significant portion of the surface water flow for agricultural beneficial use. During certain times of the year, especially during dry or critically dry years, the agricultural demand for surface water can reduce Mill Creek flow and expose in-stream barriers to fish migration. Fishery experts recognize Mill Creek as a high priority stream for the protection and enhancement of Chinook salmon spawning habitat. Mill Creek surface water diverters currently participate in a long-term cooperative management plan to help provide sufficient flow for fish migration while also maintaining irrigation supplies and the recognition of surface water rights. As part of these efforts, Mill Creek water users participate in water lease and groundwater exchange programs designed to increase in-stream flow during critical spring and fall fish migration periods. Along with other entities, the Department of Water Resources (DWR) plans to establish methods of monitoring and studying fish passage, assessing agricultural water use efficiency, and examining the potential for additional use of groundwater as opposed to use of surface water diversions in the Lower Mill Creek watershed. This report provides a background of the geology and hydrogeology in the Lower Mill Creek watershed area, a detailed discussion of the groundwater resources, and an overview of the potential for conjunctive use of surface water and groundwater resources. It also provides recommendations for additional groundwater monitoring and potentially favorable locations for production well installation associated with possible future conjunctive use programs.

Lower Tule River Irrigation District Groundwater Sustainability Agency Groundwater Sustainability Plan

Lower Tule River Irrigation District Groundwater Sustainability Agency | January 21st, 2020