Los Angeles Basin Stormwater Conservation Study Los Angeles County - PowerPoint PPT Presentation

Los Angeles Basin Stormwater Conservation Study Los Angeles County Flood Control District U.S. Department of the Interior – Bureau Of Reclamation TASK 4 – Existing Infrastructure Response & Operations Plans Analysis Public Webinar September 25, 2014

Overview  Study Background  Progress Update / Schedule  Task 4 Findings  Dams  Spreading Grounds  Channel Outlets  Next Steps Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Study Partnership Collaboration between » • Los Angeles County Flood Control District • U.S. Department of the Interior – Bureau of Reclamation Cost Estimate » $2.4 million Study Length » 3 Years Completion in December 2015 • • Task 4 Started January 2014 Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Study Objectives Study Objectives 1) Evaluate existing water conservation under future conditions 2) Evaluate potential new facilities and operational changes for a future climate Methodology • Detailed scientific, engineering & economic analyses • Coordinating with existing & proposed planning efforts • Developing partnerships & stakeholder involvement Outcome  Tool for future planning by LACFCD and other local partners Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Key Considerations  Climate Change  Population growth Los Angeles County Population Projection 14 12 Population (Millions) 10 8 6 4 2 0 1900 1925 1950 1975 2000 2025 2050 2075 2100 Year USGS - CMIP5 Global Climate Change Viewer California Department of Finance, - State and County Population Projections Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Study Area Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Study Tasks 1 Project Management 2 Water Supply & Water Demand Projections 3 Downscaled Climate Change & Hydrologic Modeling 4 Existing Infrastructure Response & Operations Analysis 5 Infrastructure & Operations Concepts 6 Trade-off Analysis & Recommendations 7 Final Report Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Major Study Tasks 2 Water Supply & Water Demand Water Supply & Water Demand Projections Projections 3 Downscaled Climate Change & Downscaled Climate Change & Hydrologic Modeling Hydrologic Modeling 4 Existing Infrastructure Response & Existing Infrastructure Response & Operations Analysis Operations Analysis 5 Infrastructure & Operations Concepts Infrastructure & Operations Concepts 6 Trade-off Analysis & Trade-off Analysis & Recommendations Recommendations Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Study Schedule ACTION SCOPE TARGET • General oversight and project guidance January 2013 TASK 1 – Study Project • Study Task Facilitation/Coordination to Management • Study Outreach ( Ongoing ) December 2015 • Water Supply & Demand Literature Review March 2014 TASK 2 – Water Supply • Supply Analysis to • LACFCD Water Conservation System Contributions & Demand Projections November 2014 • Report Review & Publishing ( In Progress ) • Downscaled Climate Change Modeling February 2013 TASK 3 – Downscaled • Hydrologic Modeling – Current/Projected to Climate Change & • Report Review & Publishing ( Complete ) December 2013 Hydrologic Modeling • Response to Current Climate September 2013 TASK 4 – Existing • Response to Future Climate to Infrastructure Response & • Report Review & Publishing ( Review Draft Report ) September 2014 Operations Plans Analysis Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Study Schedule ACTION SCOPE TARGET • Develop Concepts July 2014 TASK 5 – Infrastructure • Evaluate and Refine Concepts to • Appraisal-Level Planning & Operations Concepts August 2015 • Report Review & Publishing ( Kickoffs Soon ) • Conduct Economic Analysis • Conduct Non-Economic Analysis November 2014 TASK 6 – Trade-Off • Develop Trade-off Matrix to Analysis & • Cost Effectiveness September 2015 Recommendations • Develop Recommendations • Report Review & Publishing • Prepare Final Report June 2015 • Final Reviews TASK 7 – Final Report to • Publish and Distribute Final Report December 2015 Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Task 4 Overview  Existing Infrastructure  Task 4 Subtasks  Task 4.1 – Analyze Response to Current Climate • Investigate existing water conservation and flood control facilities  Task 4.2 – Analyze Response to Future Climate • Assess existing facilities under future climates  Dam Methodology & Results  Spreading Ground Methodology & Results  Channel Outlet Methodology & Results Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Existing Infrastructure  18 Dams 14 LACFCD o 4 Army Corps o  26 Spreading Grounds  5 Major Channel Outlets Channel Outlet Reclamation, LACFCD, LACDPW | Los Angeles Basin Stormwater Conservation Study

Task 4 Subtasks  Task 4.1 – Analyze Response to Current Climate • Investigate existing water conservation and flood control facilities o Use current operation guidelines & existing capacities o Review and update existing WMMS facility models • Analyze current climate results for stormwater  Task 4.2 – Analyze Response to Future Climate • Assess current operation guidelines & existing capacities under future climates o Analyze a range of future climate scenarios • Rank facilities for the future climate scenarios Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Task 4 Modeling Watershed Management Modeling System WMMS Update • Historic Hydrology for Existing Conditions  Water Year 1987-2000 6 Future  Baseline Conditions Climates • Projected Hydrology for Future Conditions  Water Year 2012-2095 Analyze Existing Facilities Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Future Hydrology Projections Variability in Average Annual Stormwater Runoff Volume Areal Watershed Average for WY 2012-2095 50% of Projections Maximum Variation Ensemble Mean 250% 200% 150% Percent Change 100% 50% 0% -50% -100% 2011 2023 2035 2047 2059 2071 2083 2095 Water Year Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Future Hydrology Variability Average Annual Stormwater Runoff Volume – 47 Projections Areal Watershed Average for WY 2012-2095 250% 200% 150% Percent Change 100% 50% 0% -50% -100% 2011 2025 2039 2053 2067 2081 2095 Water Year Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Future Projection Selection Average Annual Stormwater Runoff Volume – 6 Projections Areal Watershed Average for WY 2012-2095 250% 200% 150% Percent Change 100% 50% 0% -50% -100% 2011 2025 2039 2053 2067 2081 2095 High1 High2 Middle1 Middle2 Low1 Low2 Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Methodology – Dams/Reservoirs Review and Update Existing WMMS Dam F-Tables Morris Dam Storage-Discharge Relationship WMMS F-Table 1,000 900 Spillway Releases 800 700 Discharge (cfs) 600 500 F-Table "Transition Zone" Modeled Behavior 400 300 Valve Releases 200 True Behavior 100 0 0 5,000 10,000 15,000 20,000 25,000 30,000 Storage Volume (ac-ft) Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis

Dam Metrics & Criteria Analysis of the dams and reservoirs used four key stormwater metrics to determine their performance:  Average Annual Volume of Stormwater Captured or Retained  Average Annual Volume of Stormwater Discharged through Spillway  Frequency of Spillway Events  PMF Exceedance Events Ranking criteria for each of the dams included the following: D1. Historic capture efficiency D2. Future capture efficiency D3. Change in capture efficiency from historic to future D4. Historic frequency of spillway events D5. Future frequency of spillway event Bureau of Reclamation, LACFCD, LACDPW │ Task 4 – Existing Infrastructure Response & Operations Guidelines Analysis