ACTION PLAN FOR RETROFITTING THE EXISTING MS4 WITH STRUCTURAL BMPS

Transcription

1 ACTION PLAN FOR RETROFITTING THE EXISTING MS4 WITH STRUCTURAL BMPS FEBRUARY 16, 2017 For the City and County of Honolulu MS4 NPDES Permit No. HI S000002

2 STORMWATER RETROFIT BMP OPPORTUNITIES

3 Permit Requirements Status in Action Plan Action Plan Section Continue with implementation activities for Wailupe Stream, Kuli ou ou Stream and Niu Stream and provide status updates for USACE projects and City s role. Continue implementing recommendations for 2008 report, Stormwater BMPs for four major outlets at Ka elepulu Pond. Evaluate and consider recommendations for 2010 report for Wailupe watershed. Provide DOH with updated Action Plan for retrofitting structural BMPs. An inventory of potential retrofit locations emphasizing LID controls for impaired waterbodies. Wailupe Stream: USACE is currently coordinating with City and State sponsors for a scaled down project, similar to Kuli ou ou. Kuli ou ou Stream: USACE feasibility study to be completed by August Niu Stream: No ongoing activity. Phase II catch basin improvements completed. Phase II Hele Channel streambank and inlet screen retrofit to be completed in Ka elepulu Pond monitoring to extend through December No outstanding recommendations at this time Submitted February 16, 2017, to DOH. Included in Action Plan. 3, Appendix C A list of practicable retrofit projects. Included in Action Plan. 3, Appendix C A schedule for implementation of retrofit projects, subject to available funding. Included in Action Plan. 5

4 WATERSHED REGIONS

5 COMPLETED OR ONGOING PROJECTS Action Plan Section 2. Total Cost: $101M, See Table 2-1 Figures 2-2 to 2-11

6 MAP OF ONGOING/COMPLETED BMP RETROFIT PROJECTS EXAMPLE

7 TRASH REDUCTION PLAN Action Plan Section 2.4. Baseline plan recently completed Nānākuli and Nu uanu pilot projects started Ka elepulu Pond project: catch basin baskets and screens, Hele Channel Improvements

8 EROSION CONTROL BMPS PROGRAM PLAN Action Plan Section 2.5. Completed projects: Appendix B, Table B-1 Ongoing projects: Table 2-4 and Appendix B, Table B-2 Ongoing BMP Types: geoweb, amended soil and grass, concrete channel, drain inlet filters, dual infiltration chambers, sediment barriers, geotextiles and mats, grouted rubble paving, low flow showerhead, preservation of existing vegetation, rain gardens (bioretention areas), streambank stabilization, trench drain and other Ongoing BMPs Total Cost/Budget: $5.1M

9 INDUSTRIAL AND SMALL MS4 FACILITY PLANS HONOLULU POLICE DEPARTMENT Action Plan Section HPD Wahiawā Station in Progress, See Table 2-5 Grass swales Total Cost: $1.6M

10 KALIHI POLICE STATION Concrete Pad with Grooves at Fueling Area Bioswale

11 KAPOLEI POLICE STATION Vegetative Swale/Bioretention Area, Curb Cut

12 WAI ANAE POLICE STATION Curb Cut, Gravel Trench

13 INDUSTRIAL AND SMALL MS4 FACILITY PLANS HONOLULU FIRE DEPARTMENT Action Plan Section Ongoing projects at Central Fire Station, Kahalu u Fire Station, and Waipahu Vehicle Maintenance Facility See Table 2-6 Grass swales, infiltration trenches, and seepage wells Total Cost/Budget: $2.6M

14 INDUSTRIAL AND SMALL MS4 FACILITY PLANS DEPARTMENT OF PARKS AND RECREATION Action Plan Section Ongoing projects at Ala Wai Neighborhood and Community Parks See Table 2-7 Bioretention areas and amended soil and grass Total Budget: $0.45M

15 KAPI OLANI REGIONAL PARK Infiltration Area Permeable Pavement Vegetative Swale

16 MĀ ILI BEACH PARK Gravel Trench System

17 INDUSTRIAL AND SMALL MS4 FACILITY PLANS DEPARTMENT OF ENTERPRISE SERVICES Action Plan Section Ongoing project at Ala Wai Golf Course See Table 2-8 Bioretention area and permanent vegetation Total Budget: $3.3M Projects in design at Ted Makalena Golf Course and West Loch Course See Table 2-9 Permanent vegetation and downspout filters Total Budget: $2.5M

18 ALA WAI DRIVING RANGE

19 INDUSTRIAL AND SMALL MS4 FACILITY PLANS OTHER Action Plan Section Plan under development No recommendations at this time

20 HONOLULU AUTHORITY FOR RAPID TRANSIT Action Plan Section 2.7. See Table 2-10 and Appendix B, Table B-3 Infiltration basin, landscaping, vegetated swales, wet swales

21 ADDITIONAL CITY PROJECTS Action Plan Section 2.8. See Table 2-11 Seepage wells, retention basins Total Cost/Budget: $15.8M to $26.4M

22 NON-CITY BMP RETROFIT PROJECTS Action Plan Section 2.9. See Table 2-12, 2-13, and Appendix B, Table B-5 Over 140 non-city projects Biofiltration, detention basins, detention vaults, drywells, grassed yards, infiltration pipe, infiltration sumps, pervious pavement, ponding basins, rain garden, retention basin, underground detention, grassed swales, vegetated strips, landscaping, cistern/rain barrel

23 POTENTIAL STRUCTURAL BMP RETROFIT PROJECTS Action Plan Section 3. Figures 3-1 to 3-10

24 MAP OF POTENTIAL BMP RETROFIT PROJECTS EXAMPLE

25 EROSION CONTROL BMPS PROGRAM PLAN Action Plan Section 3.7. See Table 3-1 and Appendix C, Table C-1 Check dams, geotextiles and mats, geoweb, hydromulch, seeding, planting, sodding, streambank stabilization, vegetative cover. Total erosional area: 44,800 SY

26 INDUSTRIAL AND SMALL MS4 FACILITY PLANS HONOLULU POLICE DEPARTMENT Action Plan Section Kāne ohe Station, Kahuku Station HPD Training Facility, Pearl City Station See Table 3-2 and Appendix C, Table C-2 Soil amendment, subsurface infiltration, vegetated buffer Total Cost: $0.66M

27 INDUSTRIAL AND SMALL MS4 FACILITY PLANS HONOLULU FIRE DEPARTMENT Action Plan Section See Table 3-3 and Appendix C, Table C-3 Disconnect downspouts, grass swales, infiltration basins and trenches, replant vegetation, seepage wells, subsurface infiltration systems Total Cost: $6.6M

28 INDUSTRIAL AND SMALL MS4 FACILITY PLANS DEPARTMENT OF PARKS AND RECREATION Action Plan Section See Table 3-4 and Appendix C, Table C-4 Bioretention areas, disconnect downspouts, grass swales, redirect runoff to ponds and infiltration areas, retention basins, seepage pit systems, topsoil and grass, vegetated buffer Total Budget: $4.6M

29 INDUSTRIAL AND SMALL MS4 FACILITY PLANS DEPARTMENT OF ENTERPRISE SERVICES Action Plan Section See Table 3-5 and Appendix C, Table C-5 Bioretention areas, bioswales, concrete pavers, drywell, groundcover, grass pavers, gravel areas, gravel pavers, porous pavement, regrassing, stormwater storage, wood mulch Total Cost: $10M

30 PRIORITIZATION AND TRACKING Positive points assigned for: Number of retrofit objectives accomplished High density or high visibility watershed regions Addressing water quality standards Lower construction costs Drainage area as a percentage of watershed area Quantity of BMPs installed Shorter duration to implementation

31 PRIORITIZATION AND TRACKING Negative points assigned for: Lack of maintenance accessibility Permits Potential adverse environmental impacts, such as safety hazards or vectors Greater long-term maintenance costs. A tracking system to measure program trends would be implemented to validate the anticipated benefits. See Appendix D, Tables D-1 to D-4

32 IMPLEMENTATION SCHEDULE Permit Part D.1.f(1)(vi) See Table to 2020 Hydrodynamic separator, inlet screens, bioretention swales, inlet filters, pervious pavers, vegetated buffer strips, seepage wells, trench drain with filters, slope embankment stabilization, nutrient separating baffle boxes, detention basin, debris basin and channel embankment stabilization, hardline embankment area along drainage channel, roadway shoulder and embankment improvements, grassing, turf reinforcement mat

33 NEXT STEPS The next steps consist of identifying additional potential BMP retrofit locations within priority watersheds. The first phase will utilize a desktop analysis of GIS watershed maps to identify potential retrofit site areas. A field reconnaissance survey will confirm feasibility and effectiveness of the potential sites identified in the preceding desktop screening analysis.