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: rwakumoto@honolulu.govrwakumoto@honolulu.gov