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 Summary Report

U.S. Bureau of Reclamation (USBR) | November 1st, 2016

Changing demographics, climate change, and competing interests for available water supplies all present long-term risks to the stability and reliability of the region’s

Changing demographics, climate change, and competing interests for available water supplies all present long-term risks to the stability and reliability of the region’s imported water.  The region recognizes that today’s challenges require an integrated water resources management approach. For decades, this region has operated and maintained one of the most effective flood control systems in the world that protects millions of people from the impacts of flooding in the region. This system sends much of the stormwater runoff into the ocean, water that historically recharged local groundwater basins, making this region even more dependent on imported water supplies. As regulatory pressure to clean up polluted stormwater runoff continues and imported water resources diminish, this local source of water supply is becoming more and more attractive (GLAC IRWMP 2014). Many of the region’s water management agencies have studied and planned for increasing use of local recycled and graywater supplies, ocean and brackish desalination, developing more groundwater, and implementing improved water conservation initiatives to extend existing supplies. Additionally, social trends and concerns also drive the emphasis on the use of local water supplies. However, the one major local resource that has not been studied in-depth is stormwater and its opportunities to optimize the reliability of local supplies. To enhance the capabilities of the existing stormwater conservation infrastructure within the Los Angeles Basin, the LACFCD began to investigate long-term projected needs and future climate conditions within the region. Given that local groundwater plays such a vital role in the region’s water supply portfolio, detailed scientific, engineering, and economic analyses were conducted to identify strategies for enhancing stormwater capture for groundwater recharge. The LA Basin Study examined the region’s water supplies and demand, and impacts from projected population growth and changing climate in the watersheds of the Los Angeles region. The objectives of the study were to: • Use state-of-the-art climate change analysis to develop projections of future water supply and demands in the Basin. • Analyze how the Basin’s existing water infrastructure and its operations will perform in the face of changing water realities. • Develop and highlight opportunities to adapt to current and future water demands. • Conduct a trade-off analysis of identified opportunities. Concepts ranged from enhancing the existing stormwater capture system and modifying existing facilities (including those capturing runoff for groundwater recharge), to developing new structural and nonstructural concepts that could help resolve future water supply and flood risk issues. This Summary Report presents highlights of the critical tasks associated with this Basin Study and the results and findings produced throughout this collaborative study effort. Full study chapters and appendices: Plan of Study Fact Sheet Task 2: Water Supply and Demand Task 3: Climate Change Analysis Task 3.1: Development of Climate-Adjusted Hydrologic Model Inputs Task 3.1:  Climate Change and Hydrologic Projections Appendices Task 3.2:  Hydrologic Modeling Report Task 3.2: Annual Hydrologic Results Workbook Task 4: Existing Infrastructure Response & Operations Guidelines Analysis Final Report Task 5: Task 5 - Infrastructure & Operations Concept Analysis Final Report Task 6: Trade-off Analysis Final Report Click here for Reclamation's full index  including public outreach and webinars

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 Angeles Department of Water and Power Geologic Guidebook Los Angeles Aqueduct System

Los Angeles Department of Water & Power (LADWP) | December 1st, 1977

Mainstreaming Potable Water Reuse in the United States: Strategies for Leveling the Playing Field

U.S. Environmental Protection Agency (EPA) | April 18th, 2018

The practice of potable water reuse has evolved in important ways in the United States over the past 50 years, especially during the last 25 years. Prior to the 1990s, m

The practice of potable water reuse has evolved in important ways in the United States over the past 50 years, especially during the last 25 years. Prior to the 1990s, many cities and public health regulators recognized that municipal wastewater effluent accounted for a significant fraction of the surface water entering their drinking water treatment plants. Wastewater utilities generally addressed this situation by treating and disinfecting effluent consistent with Clean Water Act permitting requirements and, where feasible, minimizing the fraction of wastewater in drinking water intakes. Because of concerns associated with the presence of wastewater and contaminants from other sources (e.g., industrial pollution, agricultural runoff), some cities began to upgrade drinking water treatment plants by installing advanced treatment technologies to provide enhanced safeguards for public health protection. As water availability and water quality issues became more prevalent in rapidly growing areas, water managers soon began to explicitly consider the use of wastewater effluent to augment water supplies.

Majority of global river flow sustained by groundwater

Nature Portfolio (Springer Nature) | July 19th, 2024

Groundwater-sustained baseflow is a vital source of river flow, especially during dry seasons. The proportion of river flow sustained by baseflow—the baseflow index—i

Groundwater-sustained baseflow is a vital source of river flow, especially during dry seasons. The proportion of river flow sustained by baseflow—the baseflow index—is essential for assessing fluvial nutrient cycling and contaminant transport. However, the global baseflow index remains highly uncertain, with current Earth system model simulations ranging from 12% to 94%. Here we estimate the global baseflow index to be 59% ± 7% based on an emergent constraint approach, which integrates 50 Earth system models with baseflow indices derived from streamflow observations in 15,567 basins. Our observational constraint indicates that at least 21% ± 3% of precipitation recharges groundwater, which is approximately double the figure reported in the Sixth Assessment Report of the United Nations Intergovernmental Panel on Climate Change. Thus, our research suggests a more active role of groundwater in the global water cycle than most Earth system models currently simulate. We present evidence that the considerable disagreement in simulated baseflow stems from unrealistic and varied model representations of infiltration, aquifer structure and groundwater dynamics. These processes should be prioritized so that models can capture active groundwater–river connections.

Management of the Colorado River: Water Allocations, Drought, and the Federal Role

Congressional Research Service (CRS) | September 7th, 2022

Managing Drought in a Changing Climate: Four Essential Reforms

Public Policy Institute of California (PPIC) | September 12th, 2018

California’s climate is changing. Hotter temperatures, a shrinking snowpack, shorter and more intense wet seasons, rising sea level, and more volatile precipita

California’s climate is changing. Hotter temperatures, a shrinking snowpack, shorter and more intense wet seasons, rising sea level, and more volatile precipitation—with wetter wet years and drier dry years—are stressing the state’s water management system. Recent climate projections indicate that the pace of change will increase. To avoid unwanted social, economic, and environmental consequences, the water system will need to adapt to greater climate extremes and growing water scarcity. While California is making good progress in some areas of drought management, a more focused plan of action is needed. Successful adaptation will require strong leadership at the state and local levels, and cooperation on all fronts. The 2012–16 drought—the hottest in the state’s recorded history and one of the driest—offered a window into the future under a warming climate and lessons for managing future droughts. Using these lessons as a starting point, this report offers a road map of essential reforms to prepare for and respond to droughts in California’s changing climate. Key reforms include: Plan ahead. Stronger drought planning is critically important for urban water management, groundwater sustainability, safe drinking water in rural communities, and freshwater ecosystems. Upgrade the water grid. California needs a comprehensive program to address above- and below-ground storage, conveyance, and operational challenges by mid-century, including repairing facilities that are broken, expanding conveyance and storage capacity, and modernizing and integrating operations. Update water allocation rules. California should comprehensively update its water allocation governance. The goals should be to find equitable and efficient ways to allocate limited supplies among competing demands during dry times while promoting efforts to capture and store water during wet times. Find the money. Reliable funding is crucial for adapting to climate change. New sources are needed to pay for necessary water-management investments and to fill funding gaps in the state’s water system. The focus of this reform agenda is on drought, because drought―more than any other aspect of California’s climate―reveals the vulnerabilities of watermanagement systems. Importantly, these reforms will improve drought resilience for today’s conditions, not just for the future.