City of Los Angeles Department of Public Works Bureau of Engineering Machado Lake Ecosystem Rehabilitation Project & Wilmington Drain Multi-Use Project Community Workshop 5 February 24, 2009 In association with Overarching Goals for Machado Lake Ecosystem and Wilmington Drain Multi-Use Projects Water Quality Ecosystem Flood Management Recreation 1
Wilmington Drain Multi-Use Project Lomita Blvd. Pacific Coast Highway Riparian Woodlands Machado Lake Ecosystem Rehabilitation Project Golf Course College Freshwater Marsh Machado Lake is a popular recreation destination for local residents 2
but now the lake and park are impaired. but now the lake and park are impaired. Algae, aquatic growth, lowered oxygen Sedimentation, erosion, reduced depth Potential sediment quality concerns Trash from watersheds Limitations on use of parkland for recreation, habitat Potential flood protection concerns 3
Machado Lake Ecosystem General Project Elements Riparian Woodland Sediment removal at lake inlets Recontouring to improve dispersion of flows Exotic plant removal and replanting with native enhancements In-Lake Nutrient reduction strategies Sediment removal from bottom Aeration system Lake edge and near-shore improvements Dam improvements Machado Lake Ecosystem General Project Elements Freshwater Marsh Low flow channel Sediment removal at inlets Exotic plant removal and replanting Wetland treatment systems Harbor outfall structure repair Stormwater BMPs Trash removal at storm drains Pervious paving in parking lots Bioswales Smart irrigation controllers 4
Wilmington Drain Key Project Issues Polluted waters Destruction ti of coastal wetlands ecosystems (impacts native wildlife) Flood control Limited funding Wilmington Drain - General Project Elements Preservation of flood management capacity Trash removal systems Exotic, invasive and non-native landscaping removal and replacement with native species Channel modifications New public park 5
Project-Sponsored Public Workshops Workshop 1: Project Intro/Tour September 2008 Topics: Project background and objectives Project overall approach Project schedule Tour of lake and drain Workshop 2: Machado Lake /Wilmington Drain Today and Project Objectives October 2008 Topics: Review of objectives Habitat and biological survey Water quality and hydraulic issues Workshop 3: Machado Lake Options November 2008 Topics: Riparian woodland Lake Freshwater marsh Stormwater BMPs Workshop 4: Wilmington Drain Options January 2009 Topics: Park concepts Workshop 5: Workshop 6: Workshop 7: Workshop 8: Machado Lake and Wilmington Wilmington Alternatives Machado Lake Alternatives Recommended Projects Options (Cont) February 24, 2009 Topics: Machado Lake park concepts Use of Recycled Water Wilmington Drain Hydraulic Options April 2009 (tentative) Topics: Stream restoration/hydraulic alternatives Recommended park concept Wildlife relocation implications May 2009 (tentative) Topics: Machado Lake alternatives Wildlife relocation implications June 2009 (tentative) Agenda Welcome and Introductions Machado Lake Parkland Area Improvements Recycled Water and the Park and Lake Wilmington Channel Hydraulic Options Wrap-up and Next Steps 6
Machado Lake and Parkland Area Improvements Wendy Katagi, CDM Tom Munoz and Perry Cardoza, Nuvis Park Improvement Objectives and Concepts Develop two aesthetic park design concepts to support the projects water quality, wildlife habitat and recreational resource improvement objectives Park concepts could include: Trails, educational features, bird watching sites, seating, picnic areas, fishing and boating access Park objectives Increase and improve public recreational use and access opportunities Limiting disturbance to wildlife and sensitive habitat Limiting access to sensitive resource areas Incorporating land-based stormwater best management practices 7
Park Landscape Improvements 8
Recycled Water at the Park and Lake Jesus Gonzalez, LADWP Richard Corneille, CDM 9
Los Angeles Depends on Imported Water Most of LA s water must be transported hundreds of miles to reach our City Over 85 percent of LA s water supplies are subject to reductions and variability 19 Ongoing Water Supply Challenges Drought Impacts of climate change Court decisions Environmental commitments Competition for Colorado River water New supplies needed for our children and grandchildren 10
Securing Los Angeles Future through the Water Supply Action Plan Increase water conservation Enhance stormwater capture Accelerate groundwater cleanup and yield Implement green building initiatives Expand groundwater storage Maximize water recycling LADWP s current and planned projects in the Harbor area 11
Machado Lake Ecosystem Rehabilitation Project Recycled Water Feasibility Study Evaluated water quality and habitat impacts/benefits of using recycled water in three areas: Irrigation (Ken Malloy Harbor Regional Park and Harbor Golf Course) Wetlands enhancement (e.g., in Riparian Woodland and/or Freshwater Marsh) Lake make-up water Considered several sources of recycled water: West Basin MWD s Carson Regional Water Reclamation Plant (Title 22) City s Terminal Island Water Reclamation Plant (MF/RO) LACSD s Joint Water Pollution Control Plant Use of Recycled Water in Park and Lake could save up to 440 acre-feet of water a year Area Source Pros Cons Lake make-up water Terminal Island Potable Water savings up to 203 acre-feet/year Higher levels of nitrogen and phosphorous than (MF/RO) Ability to maintain constant lake level and possibly a deeper lake potable water Wetlands Enhancement Irrigation (park and golf course) West Basin (Title 22) or Terminal Island (MF/RO) West Basin (Title 22) Potable water savings up to 82 acre-feet/year Increases pollutant removal through wetlands Increases habitat Potable water savings up to 155 acre-feet/year Increases overall water use Potential permitting hurdles Golf course greens may be sensitive to salt levels One acre-foot is enough water to supply two average families in Southern California for a year! 12
Wilmington Channel Hydraulic Options Stephanie Bache, Parsons Key Design Objectives for Wilmington Channel Integration of Multiple Objectives 50-yr storm conveyance Habitat/Permittable Water Quality Pacific Coast Hwy. Golf Course 13
Key Design Considerations for Wilmington Channel 50-yr. Storm Conveyance Impervious cover in watershed has increased Sediment deposition in the channel has diminished storage capacity Vegetation has decreased conveyance ability Limited acreage for detention capacity Permitting Limit impacts to high quality habitat Limit impacts of maintenance activities Mitigation g through onsite habitat improvement WQ Management Sedimentation basin North of Lomita Blvd. could impact high quality habitat Trash net structures may result in head loss Pacific Coast Hwy. Golf Course Habitat Considerations - Wilmington Channel 14
Wilmington Channel Longitudinal Profile 26 24 2007 channel invert 1977 channel invert Lake Level PCH Lomita Blvd Hwy 110 22 20 18 Elevation (ft) 16 14 12 Machado Lake 10 8 6 4-4000 -3000-2000 -1000 0 1000 2000 3000 4000 5000 6000 River Station (ft) Wilmington Channel Longitudinal Profile 26 24 2007 channel invert PCH Lomita Blvd Hwy 110 1977 channel invert 22 Bank (lower elevation) 20 18 Elevation (ft) 16 14 12 10 8 6 4-4000 -3000-2000 -1000 0 1000 2000 3000 4000 5000 6000 River Station (ft) 15
Wilmington Channel Longitudinal Profile 26 24 1977 conditions 2007 channel invert PCH Lomita Blvd Hwy 110 22 1977 channel invert Bank (lower elevation) 20 18 Elevation (ft) 16 14 12 10 8 6 4-4000 -3000-2000 -1000 0 1000 2000 3000 4000 5000 6000 River Station (ft) Wilmington Channel Longitudinal Profile 26 2007-current condition PCH Lomita Blvd Hwy 110 24 1977 conditions 2007 channel invert 22 1977 channel invert Bank (lower elevation) 20 18 Elevation (ft) 16 14 12 10 8 6 4-4000 -3000-2000 -1000 0 1000 2000 3000 4000 5000 6000 River Station (ft) 16
35 30 25 20 15 10 5 0 100 200 300 400 Station (ft) Example Design Options Evaluated Clean box culverts Add new culverts Perform maintenance in main channel Re-grade channel and excavate sediment Construct detention basin Breach weir at PCH Design retreating trash net Re-grading in Wilmington Channel Remove blockage upstream of island Area = ~ 12,340 ft 2 East (Left) Island West (Right) 4. Clear main channel and banks along island to lower friction L.A. County F.C.D Channel centerline Cut area 17
Maintenance in Wilmington Channel Definitions Cleaning: removal of sediment and debris from existing culverts Clearing: maintenance in main channel removal of vegetation, debris, biomass Excavation: regrading of existing topography Wilmington Drain downstream of Lomita Blvd. Wrap-up and Next Steps 18
Next Steps Next Community Workshop: April 21, 2009 Wilmington Drain Alternative(s) Wilmington Drain Recommended Park Concept Potential Wildlife Relocation Implications www.lapropo.org Questions? 19