LA County’s Green Street Task Force: Stormwater & Transportation working together

1. LA County’s Green Street Task Force: Stormwater & Transportation working together TJ Moon County of Los Angeles Department of Public Works

2. Los Angeles County Stormwater Quality Nutrients Trash 33 TMDLs l Metals Bacteria Leads Nation Toxics

3. Stormwater Quality Solutions Regional Projects Green Streets Low Impact Development

4. How Much Green Streets Do We Need?

5. Green Street Task Force Participants • Stormwater Quality • Road Maintenance • Transportation Planning • Traffic & Lighting • Geotechnical • Parks and Recreation Objectives • Collaboration • Sustainability • Efficiency

6. Stormwater Green Street Master Plan Question: • Where are the most optimal locations to construct Green Streets to address stormwater quality? Master Plan Goal: • Create Prioritization Process • Identify top 100+ half-mile road segments 5336 Total Miles

7. Screening Process Overview County Roads Phase 1 Screening Phase 2 Screening Phase 3 Screening Phase 4 Feasibility Field Recon Steep Slope Geotechnical Modeling Utilities Contamination Groundwater Table Final Site Selection Environmental Geotechnical

8. Phase 1 Screening Phase 1 Screening Steep Slope Slope > 5% Contamination 60 feet buffer from contamination sites 40% Remain 60% Out 5,336 Total Miles

9. Phase 2 Screening Phase 2 Screening Phase 2 Phase 1 Geotechnical • Landslides • Bedrock • Liquefaction • Seismic • Surface Soils Groundwater Table • GW depth Varies • Usually more than 10+ feet • Not Considered 40% Remain 60% Out 36% Remain 64% Out

10. Phase 3 Screening Phase 3 Screening Phase 2 Modeling • Impervious drainage area drives water quality need 36% Remain 64% Out

11. Phase 3 Screening Tributary Area Step 1: Identify catch basins and open channels

12. Phase 3 Screening Tributary Area Step 2: Cluster catch basins to create downstream node

13. Phase 3 Screening Tributary Area Step 3: Digital Elevation Model + Flow Direction

14. Phase 3 Screening Tributary Area Step 4: Drainage Area Delineation

15. Phase 3 Screening Impervious Area Step 5: Impervious Score

16. Phase 3 Screening Storm Drain Step 6: Qualitative Selection • Major storm drain • Large Parkway Space • Maximize Drainage Area

17. Phase 3 Screening Phase 2 Phase 3 Screening Phase 3 Modeling • Impervious drainage area drives water quality need Final Site Selection • Top 110 Sites Selected • 55 Miles 36% Remain 64% Out 99% Out

18. Phase 4 Feasibility Phase 4 Feasibility Field Recon Utilities • IPad entry • GPS • Photos • Automatic reporting • Existing Substructure Map • Recording of Dig Alert for Geotech Field Recon Utilities Environmental Geotech Phase 1 Assessment • 3 CPTs per Site • 330 Total CPTS • 80’ Deep Environmental Geotechnical

19. Phase 4 Feasibility - Geotechnical • 110 Potential Sites • 3 Cone Penetration Tests per Site • 80 Feet Deep • Full Understanding of Soils • Soils will dictate the BMP Type Sand Clay

20. 10 Feet Deep Phase 4 Feasibility - Geotechnical Sand Clay • How do we maximize infiltration? • Take advantage of sandy soils • Depth may be deeper • Adjust BMP for sandy soil 75 Feet Deep 60 Feet Deep 50 Feet Deep 30 Feet Deep 40 Feet Deep 20 Feet Deep

21. Lessons Learned • Lesson Learned #1 • Not enough space to capture sufficient stormwater • Solution • Go deeper – Infiltration Wells • Regional Green Streets

22. Lessons Learned Existing Storm Drain Dry Wells • Solution • Green Alley Master Plan • Lesson Learned #2 • Alleys are a great location

23. Measure W Tax Measure passed on November 2018 Estimated Revenue: $300 M SAFE CLEAN WATER PROGRAM

24. Stormwater & Transportation Coming Together

25. Stormwater & Transportation Coming Together • Project Planning can include: • Road Rehabilitation • Safety (Vision Zero) • Connectivity Corridors • Stormwater Capture • Native Landscaping • Heat Island Effect • Multiple Funding Sources!

26. Safety: Vision Zero Street East Rancho Dominguez Street Improvement Project Stormwater Capture Feature Compton Blvd Road Improvement Limits Road Improvement Limits E. Rancho Dominguez Park Atlantic Ave E. Rancho Dominguez Library • Connect Library + Parks • Enhance Safety Ex. Storm Drain

27. Contact Information Paul Alva palva@dpw.lacounty.gov (626) 458-4325 TJ Moon tmoon@dpw.lacounty.gov (626) 458-4380