UPDATE ON: Water Quality Enhanced BMPs / Landscaping. January 2017

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1 UPDATE ON: Water Quality Enhanced BMPs / Landscaping January 2017

2 Technical Studies in Preparation Water Quality Assessment Report Hydrology Study Storm Water Data Report Flood Control Facilities Report Enhanced Landscaping Concepts BMPs (Storm Water Treatment) Planting / Aesthetics

3 Motion 22.1 Objectives Implement Additional BMPs Maximize Planting LA River Resources Ensure Consistency with RWQCB Permit Identify BMP Locations Enhance LA River Water Quality Add Trees, Shrubs, Foliage within R/W consistent with Caltrans Policy Landscaping Criteria: Drought Tolerant Superior Biosequestration Superior Biofiltration Exceed remove/replace ratio Minimize Impacts to Riverbanks, Native Landscaping, and Nearby Open Space Minimize Impacts to Trails and Pocket Parks

4 Water Quality What is Affected? Receiving Water Bodies Los Angeles River Estuary Reach 1 Reach 2 Compton Creek Rio Hondo Channel Reach 1 Dominguez Channel Los Angeles/Long Beach Inner Harbor

5 Current Regulations & Conditions Caltrans Statewide Storm Water Management Plan (SWMP) Amended July 2016 Complies with National Pollution Discharge Elimination System (NPDES) Permitting Requirements Provides Guidance on Best Management Practices (BMPs) Construction Site Design Pollution Prevention Treatment Control Corridor Storm Water Management Studies Caltrans Completed in 2009 for I-710 Identified Treatment Opportunities on Existing I Recently Installed Treatment BMPs within Project Limits: Biofiltration Swales/Strips Gross Solids Removal Devices (GSRD) Media Filters Infiltration/Detention Basins

6 System Overview: Existing P Storm Water Runs Off Roadway and is Collected in Inlets Water is Conveyed in Pipe Network to Pump Station Water is Pumped to an Outlet in the LA River Channel

7 System Overview: With Treatment BMP P Storm Water Runs Off Roadway and is Collected in Inlets Water is Conveyed in Pipe Network to BMP Treated Water is Conveyed to Pump Station Water is Pumped to an Outlet in the LA River Channel

8 Project Impacts to Water Quality Alternative 5C Impervious Surface Area: 17% Increase for Alternative 5C 26% Increase for Alternative 7 Increases in Impervious Surface Area Increase Pollutant Load BMP Alternative 7 Treatment Required to Maximum Extent Practicable: BMP Existing + New Run Off No Additional Right of Way Acquisition Involving Displacements Feasibility of Design

9 BMPs for Project Alternatives Alternative 5C Alternative 7 Candidate Treatment BMPs 40 Biofiltration Swales 32 Infiltration / Detention Basins 12 Media Filters 8 GSRDs Preliminary Estimates 74% of Total Paved Area is Treated $165M (All BMPs) Candidate Treatment BMPs 36 Biofiltration Swales 30 Infiltration / Detention Basins 12 Media Filters 8 GSRDs Preliminary Estimates 78% of Total Paved Area is Treated $302M (All BMPs)

10 Typical Treatment BMPs Infiltration Basins Biofiltration Swales Media Filters Larger Footprint Usually Placed in Wider Interchange Spaces Hydroseed Typical Landscaping Treatment Linear Footprint Usually Placed Along Roadways Hydroseed Typical Landscaping Treatment Smaller Footprint Usually Placed in Confined Areas Earthen Types Preferred if Space Permits

11 Enhancement Concept: Infiltration Basin Existing Southbound I-710 near Firestone Boulevard Thematic Elements Planting / Hardscape Mix Tank Screened Perspective

12 Enhancement Concept: Infiltration Basin Existing Southbound On Ramp at PCH Thematic Elements Planting / Hardscape Mix New Ramp Configuration Industry Uses Screened Perspective

13 Enhancement Concept: Biofiltration Swale Existing Southbound I-710 near Florence Avenue Thematic Elements Planting / Hardscape Mix New Ramp Configuration Perspective

14 Existing Landscaping Example: Imperial Highway: Existing Condition

15 Proposed Landscaping Example: Increase Number of Trees Added Shrubs and Ground Cover Landscaped Parkway North Side of Imperial Over River Over Freeway Class 1 Bikeway Multiple Trail Access Points

16 Effects on LA River Amenities: More Trail Access From Parkway From Wright Rd Access Point Enhancements Landscaping Lighting Wayfinding Signs Net Increase in Adjacent Open Space

17 Project Consistency with Motion 22.1 Objectives Implement Additional BMPs Maximize Planting LA River Resources More than 90 BMP Locations Identified BMPs Treat Existing and Proposed Run Off as Much as Possible Plan Complies with NPDES More Trees, Shrubs, Ground Cover within R/W Integrated with Treatment BMPs Effective Design Pollution Prevention BMP Minimizes Impacts to Riverbanks, Native Landscaping, and Nearby Open Space Increases Trail Access Enhances Access Points and User Experience