Storm Water Quality

Storm Water Management Program Plan

The City is required to develop and implement a Storm Water Management Program Plan (SWMPP) because Oʻahu’s storm drain system is regulated under a National Pollutant Discharge Elimination System (NPDES) permit* The SWMPP includes the following Chapters:

Chapter 1 – Program Administration – discusses the roles and responsibility for each City department/agency for administering the SWMPP. Discussions on public involvement/participation, reporting requirements, City databases, and potential Storm Water Utility have also been incorporated into this chapter.

Chapter 2 – Public Education and Outreach Program – describes the various methods that are used to engage the public in storm water awareness events and also engage private businesses in identifying BMP solutions that are most applicable/relevant to their operations.

Chapter 3 – Illicit Discharge Detection and Elimination Program – describes the multi-faceted approach the City has taken to proactively seek and respond to potential sources of non-storm water discharges into its MS4.

Chapter 4 – Construction Site Runoff Control Program – explains how the City has integrated temporary storm water BMP requirements into the design and construction phase of projects under its jurisdiction.

Chapter 5 – Post-Construction Storm Water Management in New Development and Redevelopment Program – describes the City’s requirements for the permanent, long-term management of storm water following the construction phase.

Chapter 6 – Pollution Prevention/Good Housekeeping Program – examines the City’s island-wide efforts to reduce polluted discharge to and from the MS4. Pollution prevention efforts at City-owned facilities are discussed in Chapter 8.

Chapter 7 – Industrial and Commercial Activities Discharge Management Program – details the City’s targeted focus on environmental compliance at privately owned industrial and commercial facilities.

Chapter 8 – City Facilities BMP and Monitoring Program – discusses the City’s inspection and monitoring program to reduce pollutants from City-owned facilities.

Chapter 9 – Training – describes the training requirements from all components of the SWMP.

Chapter 10 – Monitoring Requirements – explains the extensive efforts by the City to undertake a comprehensive water quality monitoring and activity tracking and reporting program.

Chapter 11 – Total Maximum Daily Load Wasteload Allocation Monitoring Program – quantitatively determines pollutant removal to demonstrate compliance with the annual or seasonal reduction goals stipulated in the City’s Permit.

Chapter 12 – Program Effectiveness Assessment Plan – describes the City’s process for evaluating the effectiveness of the program and improving it over time.

* In 1990, the Environmental Protection Agency (EPA) issued rules that required all municipalities with a population of over 100,000 to obtain NPDES permif Health. The City first received its MS4 permit in 1994 for the five-ts for their storm drain systems. The EPA has delegated permitting authority in Hawai‘i to the State Department oyear period from 1994 to 1999 and has updated and renewed the permit continuously ever since.

The most current permit, NPDES Permit No. HI S000002, was issued on August 7, 2020 by the Hawai‘i Department of Health to the City and County of Honolulu. The effective date is September 1, 2020 until midnight, August 31, 2025.

To access the Storm Water Management Program Plan document and appendices, click here.

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