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Local Plans, Regulations, or Policies Local Plans, Regulations, or Policies Supporting Green InfrastructureSupporting Green Infrastructure
City and County of HonoluluCity and County of HonoluluDepartment of Facility Maintenance – Storm Water QualityDepartment of Facility Maintenance – Storm Water Quality
Randall Wakumoto, P.E., Branch HeadRandall Wakumoto, P.E., Branch Head
PLEASE HELP PROTECT OUR WATERS…FOR LIFEPLEASE HELP PROTECT OUR WATERS…FOR LIFENOAA GREEN INFRASTRUCTURE WORKSHOPNOAA GREEN INFRASTRUCTURE WORKSHOP
October 2015
collectcollect
collectcollect
surface runoff
ILLICIT DISCHARGEILLICIT DISCHARGE
draindrain
Non-Point Source PollutionNon-Point Source Pollution
Water PollutionWater Pollution
STORM WATER MANAGEMENT PROGRAMSTORM WATER MANAGEMENT PROGRAMREQUIRED ELEMENTSREQUIRED ELEMENTS
Public Participation Public Participation & Outreach& Outreach
Pollution Prevention Pollution Prevention and Good and Good HousekeepingHousekeeping
Construction Construction Site Runoff Site Runoff
ControlControl
Post Post Construction Construction Storm Water Storm Water ManagementManagement
Industrial & Industrial & Commercial Commercial DischargeDischargeMonitoring & Monitoring &
Implementation Implementation PlansPlans
Illicit Discharge Illicit Discharge Detection & Detection & EliminationElimination
Reducing pollutant discharge from new Reducing pollutant discharge from new development & redevelopment construction sitesdevelopment & redevelopment construction sites
Post Construction Storm Water Post Construction Storm Water Management Management
Pollution Pollution Prevention Prevention BMPsBMPs
Site Site Design Design BMPsBMPs
Treatment Treatment BMPsBMPs
Structural Structural Source Source Control Control BMPsBMPs
BACKGROUNDBACKGROUND
(MS4)(MS4)
discharge
RECEIVING RECEIVING WATERSWATERS
MUNICIPAL MUNICIPAL SEPARATE SEPARATE
STORM STORM SEWER SEWER SYSTEMSYSTEM
MS4 PERMIT
Reissued JAN 15, 2015Reissued JAN 15, 2015
Permit Became Effective Permit Became Effective on FEB. 16, 2015on FEB. 16, 2015
Permit Exprires on Permit Exprires on JAN 15, 2020 JAN 15, 2020
BACKGROUNDBACKGROUND
EPA MS4 Audit conducted on April 23-25, 2013EPA MS4 Audit conducted on April 23-25, 2013
City received a Notice of Apparent Violation Letter on City received a Notice of Apparent Violation Letter on October 16, 2013October 16, 2013
Post Construction BMP Program – Potential ViolationsPost Construction BMP Program – Potential Violations
• Inadequate Training for City InspectorsInadequate Training for City Inspectors
• Exemptions under Current City Revised Drainage Exemptions under Current City Revised Drainage StandardsStandards
• Inconsistent application of LIDs for smaller sitesInconsistent application of LIDs for smaller sites
• Lack of guidance for preferential BMPsLack of guidance for preferential BMPs
Revised Drainage Revised Drainage StandardsStandards Current City Revised Drainage Standards Current City Revised Drainage Standards
became effective on June 1, 2013 became effective on June 1, 2013 Deadline to submit revised standards up Deadline to submit revised standards up
to 18 months after effective date of permitto 18 months after effective date of permit
(~August 2016)(~August 2016)
CURRENTCURRENTDrainage Standards SummaryDrainage Standards Summary
Priority Description
A1 Disturb ≥ 5 acres of land during construction
A2 Disturb 1 - 5 acres of land during construction
BDisturb < 1 acre during construction, create at least 10,000 sq-ft of total impervious surface, and is a Retail Gas Station, Auto Repair Shop, Restaurant and Parking Lot
REVISEDREVISEDDrainage Standards SummaryDrainage Standards Summary
Priority Description
A Disturb ≥ 5 1 acres of land during construction
A2 Disturb 1 - 5 acres of land during construction
B
Disturbs < 1 acre during construction, has at least 10,000 sq-ft of total impervious surface, and is a Retail Gas Station, Auto Repair Shop, Restaurant, Parking Lot, RetailMall, Industrial Park, Building > 100 ft tall
BMP Type Sizing Criteria
Volume Based Rainfall depth of 1 inch
Flow Based Rainfall intensity of 0.4 in/hr
Area Based10% of contributing areaor100% of contributing flow path
Demand Based80% of total annual runoff is capturedand80% of total annual reuse demand is met
BMP Sizing CriteriaBMP Sizing Criteria
1. Either Harvest/Reuse or Treat on-site with non-LID BMPs, any portion of the WQV that is not retained or biofiltered
• Detention Basin• Sand Filter• Manufactured Treatment Device (eg, hydrodynamic
separator)
2. Retain or biofilter at an offsite location, the volume of runoff equivalent to the portion of the WQV that was not retained and/or biofiltered on-site
• Proposed location must be approved by City• Applicant responsible for all costs, including
maintenance
Alternative Compliance OptionsAlternative Compliance Options
Source Control BMPsSource Control BMPsLow-technology practices designed to prevent pollutants from contacting storm water runoff and/or prevent discharge of contaminated runoff to the MS4
Gas station, Kapolei, HI
• Stenciling storm drain inlets
• Covering fueling and storage areas
• Grading dumpster, fueling, and storage areas to prevent run-on & runoff
• Using dumpsters with lids
• Paving high risk areas with concrete instead of asphalt
Treatment Control BMPsTreatment Control BMPsFlow through based practices designed to settle, filter and remove pollutants within storm water runoff
Catch Basin Filter
• Catch Basin Inlet Filters
• Hydrodynamic Separators
• Vegetative Buffer Strips
• Vegetative Swales
CDS Hydrodynamic Separator
Low Impact Development (LID) Low Impact Development (LID) BMPsBMPs
LID treatment measures include harvesting and reuse, infiltration, evapotranspiration or biotreatment of storm water runoff as close to its source
• Infiltration Basins
• Bioretention
• Green Roofs
• Permeable Pavement
• Cisterns/Rain Barrels
Cistern
Green Roof
http://www.honoluludpp.org/ReportsNotices/StormWaterQualityPage.aspx http://www.honoluludpp.org/ReportsNotices/StormWaterQualityPage.aspx
1.Conserve Natural Areas, Soils, and Vegetation
2.Minimize Disturbances to Natural Drainages
3.Minimize Soil Compaction
4.Minimize Impervious Surfaces
5.Direct Runoff to Landscaped Areas
LID Site Design StrategiesLID Site Design Strategies
http://www.honoluludpp.org/ReportsNotices/http://www.honoluludpp.org/ReportsNotices/StormWaterQualityPage.aspx StormWaterQualityPage.aspx
• 117 waterbodies on 2014 303(d) List
• 319 total pollutant listings
non-LID BMPs don’t address Pollutants of Concern
Not removed by non-LID BMPs Removed by non-LID BMPs
Why LID’s?Why LID’s?
LID Flow Reduction BenefitsLID Flow Reduction BenefitsInfiltrationPermeable Pavement
BioretentionGreen Roof
Enhanced SwaleHarvesting/Reuse
Downspout Disconnect
Vegetated SwaleDetention Basin
Sand FilterMTD
20 40 60 80 100
*Center for Watershed Protection, 2008*Center for Watershed Protection, 2008
Percent Runoff Reduction*Percent Runoff Reduction*
LID Additional BenefitsLID Additional Benefits
http://water.epa.gov/infrastructure/greeninfrastructure/index.cfmhttp://water.epa.gov/infrastructure/greeninfrastructure/index.cfm
LID Requirements for all new development and redevelopment projects greater than 1 acre (Priority A and B)
Expand the types of smaller projects for post-construction BMPs (Priority B) to include Parking Lots greater than 20 stalls Buildings greater than 100-feet tall Retail Malls Industrial Parks
Require 1.5x the Water Quality Volume (WQV) for any treat and release practices (i.e. biofiltration)
Storm Drainage Standards UpdateStorm Drainage Standards Update
Requirement to prepare a separate Post-Construction BMP Plan that identifies both LID, Treatment and Source Control BMPs on the drawing
Requirement for submitting a Storm Water Applicability Checklist that prioritizes and identifies the need, type and location for permanent post-construction BMPs.
Requirement for submitting Storm Water Checklist for all applicable projects that includes O&M Plan outlining inspection and maintenance responsibilities.
Storm Drainage Standards Update Storm Drainage Standards Update (Cont’d)(Cont’d)
Expand on City’s Storm Water BMP Guide to include a risk ranking process (low, medium and high) for prioritizing BMP selection that factors in maintenance performance and pollutant removal effectiveness for site specific pollutants of concern.
Requirement for submitting a Covenant Master Agreement or similar document that must be signed by the owner/developer or authorized representative.
Requirement for a Certificate of Completion to be signed prior to permit closure to confirm that the BMPs have been installed in conformance to the approved construction plans.
Storm Drainage Standards Storm Drainage Standards Update Update (Cont’d)(Cont’d)
Waikiki Shell / Kapiolani Park Parking LotWaikiki Shell / Kapiolani Park Parking Lot
Grass Pavers and Vegetative Swales
Waimanalo (Kumuhao Street)Waimanalo (Kumuhao Street)
Biofiltration Swales
Ala Wai Golf CourseAla Wai Golf CourseVegetative Buffer Strips
Maili Beach Park Parking LotMaili Beach Park Parking LotGraveled Infiltration Trench
HPD Kalihi Police StationHPD Kalihi Police StationBiofiltration Swale
LID ConsiderationsLID Considerations Plan ahead and coordinate with design team (i.e. soils
engineer, landscape architect, structural engineer, etc.) to bring them on board as early as possible
Evaluate site specific conditions to identify pollutant sources and pollutants of concern when selecting LID options, as well as consider site constraints that could make implementing LID infeasible
Develop detailed language in specifications that outlines contractor responsibilities when installing any LID designs
Heavily factor in operations and maintenance activities when selecting LID and establish programs and funding alternatives with client in advance to address this critical issue
Honolulu Zoo Parking Lot – Bioretention Honolulu Zoo Parking Lot – Bioretention (Rain Gardens)(Rain Gardens)
BEFOREBEFORE AFTERAFTER
Maintenance is CriticalMaintenance is Critical
Public Education and OutreachPublic Education and Outreach
Knowledge and Awareness leads to Knowledge and Awareness leads to changechange
QUESTIONSQUESTIONS
THANK YOUTHANK YOU
www.cleanwaterhonolulu.comwww.cleanwaterhonolulu.com
City & County of HonoluluCity & County of HonoluluDepartment of Facility Department of Facility
MaintenanceMaintenance
Environmental Concern LineEnvironmental Concern Line
768-3300768-3300
For More For More Information:Information:
RANDALL WAKUMOTO, RANDALL WAKUMOTO, BRANCH HEADBRANCH HEAD
Storm Water Quality BranchStorm Water Quality BranchPh: 768-3242Ph: 768-3242
Email: Email: [email protected]@honolulu.gov