1. Department of Public Works NPDES Low Impact Development and Green Streets Resolutions City Council August 17, 2015

2. Department of Public Works It is recommended that the City Council: 1.Find the resolutions proposed herein to be exempt under the California Environmental Quality Act (CEQA) in accordance with Title 14 Chapter 3, Class 8, Section 15308, actions taken by regulatory agencies to assure the maintenance, restoration, enhancement, or protection of the environment 2.Adopt a resolution approving the amended Stormwater and Urban Runoff Pollution Control Legal Authority for New or Redevelopment Projects to expand the existing Standard Urban Stormwater Mitigation Plan (SUSMP) requirements by imposing Low Impact Development (LID) strategies and Green Streets policies 3.Adopt a resolution approving a Green Streets policy for transportation corridors on publicly-owned street and road projects 4.Repeal Resolution No. 8151, which addressed the stormwater and urban runoff control regulations under the previous Municipal National Pollutant Discharge Elimination System (NPDES) Permit. 2 Recommendation

3. Department of Public Works December 28, 2012 – New Municipal Separate Storm Sewer System (MS4) Permit became effective June 2013 – Notice of Intent to develop an Enhanced Watershed Management Program (EWMP) & Coordinated Integrated Monitoring Program (CIMP) with other agencies submitted to Los Angeles Regional Water Quality Control Board (Regional Board) June 28, 2015 – EWMP & CIMP submitted to the Regional Board June 28, 2015 – Low Impact Development (LID) and Green Streets requirements in effect 3 Background

4. Department of Public Works Components of the Low Impact Development: > Capture and treat storm water on site, before it runs off the parcel (rain barrels, infiltration areas) > Focus on infiltration/biotreatment > Design requirements and prescriptive language Large number of small projects have significant effect on pollutant reduction Minimize impervious area and control runoff from impervious surfaces through infiltration 4 Low Impact Development

5. Department of Public Works Projects requiring Low Impact Development: > Development ≥ 1 acre if 10,000 ft 2 will be impervious > Industrial/commercial ≥ 10,000 ft 2 > Automotive service, gasoline outlets, restaurants and parking lots ≥ 5,000 ft 2 > Significant Ecological Areas ≥ 2,500 ft 2 > Redevelopment ≥ 5,000 ft 2 > Roads, streets, highways ≥ 10,000 ft 2 > Hillside SFR (limited requirements) 5 Low Impact Development Categories

6. Department of Public Works 6 Low Impact Development Previous RequirementsNew LID Requirements Design Requirements Can use any Best Management Practice (BMP) Tiered requirements: 1.Infiltration 2.Harvest & use 3.Biotreatment Infiltration not RequiredMust deem infiltration and harvest & use infeasible prior to using biotreatment Treat 0.75-inch, 24-hour rain event Same numerical criteria for all BMPs No Specification Treat 0.75-inch, 24-hour rain event or the 85th percentile, 24-hour rain event, whichever is greater Biotreatment BMPs must be sized to 1.5 times the design volume Prescriptive design specifications

7. Department of Public Works 7 Low Impact Development Low Impact Development BMPs

8. Example Project #1 Department of Public Works Pasadena Hotel (Colorado Blvd.) Site characteristics > Building addition to existing hotel > 0.25 acres > 84% impervious > 1 drainage area > Stormwater Volume for site = 693 cubic feet > Infiltration infeasible > Biotreatment BMPs must be sized to 1.5 times the stormwater volume for the site 693 cubic feet x 1.5 = 1040 cubic feet

9. Example Project #1 – Planter Box Department of Public Works Proposed BMP – Flow Through Planter Box Using design standard, minimum area needed for the BMP is 692 square feet Various size configurations could be selected

10. Example Project #1 – Alternative option (Tree Box) Department of Public Works Proposed BMP – Proprietary Tree Box Using manufacturer sizing standard, BMP unit needed = 4x6

11. Example Project #2 Department of Public Works Hudson & Walnut Site characteristics > Multiple story building > 0.84 acres > 90% impervious > 3 drainage areas > Stormwater Volume for site = 2,245 cubic feet > Infiltration infeasible > Biotreatment BMPs must be sized to 1.5 times the stormwater volume for the site 2,245 cubic feet x 1.5 = 3,367 cubic feet

12. Example Project #2 - Planter Box & Tree Box Department of Public Works Stormwater storage tank Stormwater storage tank Proposed BMPs – Proprietary Tree Box and Flow Through Planter Box and Storage Tank Utilize stormwater storage tank to reduce planter box size

13. Example Project #3 – Existing Project in West Hollywood Department of Public Works Approved and built project in the City of West Hollywood Site characteristics > Mixed Use Building > 0.87 acres > 95% impervious > 2 drainage areas > Stormwater Volume for site = 2,310 cubic feet > Infiltration infeasible > Biotreatment BMPs must be sized to 1.5 times the stormwater volume for the site 2,245 cubic feet x 1.5 = 3,456 cubic feet Proposed BMPs –Storage Tank and Flow Through Planter Box

14. Department of Public Works Green Streets Policy requires the use of strategies for transportation corridors > Modeled after LA County’s Green Streets policy > Reference Document: USEPA guidance regarding Managing Wet Weather with Green Infrastructure: Green Streets Required for construction of ≥ 10,000 SF of impervious area in transportation corridors Does not include routine maintenance activities to maintain the original street alignment and elevations > Exempt activities include:  Slurry seal  Resurfacing - grind and overlay 14 Green Streets

15. Department of Public Works 15 NPDES Questions ?