State of Hawaii Department of Transportation, Highways Division

Storm Water Post-Construction Best Management Practices Manual

StateHawaiihighNo

Fields not found in document: design_criteria.design_storm_return_periods_years, design_criteria.required_hydrologic_hydraulic_software

Other manuals in Hawaii: City and County of Honolulu

Document Metadata

Jurisdiction level

state

“State of Hawaii Department of Transportation Highways Division”
Title Page

State

Hawaii

“State of Hawaii Department of Transportation”
Title Page

Version / edition

December 2021 (Revision No. 1)

“December 2021”
Title Page; Record of Revision

Adoption / effective date

2021-12-01

“Revision No. 1 December 2021 Revised criteria for MS4 NPDES Permit areas”
Record of Revision

Last revised date

2021-12-01

“Revision No. 1 December 2021”
Record of Revision

Relationship to state manual

independent

“Private construction projects located outside the DOT-HWYS right-of-way are considered to be in compliance with post-construction BMP requirements if the project complies with the storm water quality requirements of the applicable county.”
Section 3.1.3, Page 3-3

Design Criteria

Design storm return periods (years)

Not found in document

No evidence cited

Water quality volume method

Volume-based treatment uses Water Quality Volume (WQV) = P × C × AT × 3630, where P is a 1-inch design storm runoff depth representing the statewide 85th-percentile 24-hour storm; C = 0.95 for impervious highway surfaces. Flow-based treatment uses Water Quality Flow Rate (WQFR) = C × i × AT with Rational Method rainfall intensity i = 0.4 in/hr maintainable for at least three hours.

“WQV = P x C x AT x 3630 Where WQV = Water Quality Volume (ft3) P = Design Storm Runoff Depth (inches) = 1 inch”
Section 7.3.1, Page 7-6

Peak flow calculation method(s)

Rational Method

“Flow rate calculation shall be based upon the Rational Method as follows: WQFR = C x i x AT”
Section 7.3.2, Page 7-7

Required hydrologic/hydraulic software

Not found in document

No evidence cited

Approved BMP categories

Vegetated Buffer Strip, Vegetated Swale, Enhanced Swale, Infiltration Trench, Infiltration Basin, Bioretention Facility, Permeable Pavement, Pocket Wetland, Rainwater Harvesting, Tree Box Filter, Wet Pond, Wet Extended Detention Pond, Sand Filter, Drain Inlet Filter, Modified Catch Basin, Oil and Grit Separator, Centrifugal Hydrodynamic Separator, Multi-Stage Hydrodynamic Separator, Source Control BMPs

“LID TREATMENT CONTROL BMPs: Vegetated Buffer Strip, Vegetated Swale, Enhanced Swale, Infiltration Trench, Infiltration Basin, Bioretention Facility, Permeable Pavement, Pocket Wetland, Rainwater Harvesting, Tree Box Filter”
Appendix A, Page v