Urban Sub-basin Action Plan

Goal: The Urban Sub-basin Action Plan (USBAP) assess urban areas and other developed lands that contribute to non-point source pollution in Ko’olaupoko using ecological-based  metrics and social inputs to prioritize opportunities for Low-Impact Retrofits(LIR) implementation.

Objective: Where appropriate the Urban Sub-Basin Action Plan (USBAP) shall inform and guide the implementation of projects that shall restore to the fullest extent possible a site's pre-development hydrology by using Low Impact Retrofit design techniques that infiltrate, filter, store, evaporate and detain runoff as close to its source as possible.

Guiding principle: The Urban Sub-basin Action Plan (USBAP) will provide a course of action for Hui o Ko’olaupoko (HOK) over the next several years to address storm water and non-point source pollution in a prioritized effort the Ko’olaupoko moku. 

This site is prone to ponding after heavy rains.

LIR mock-up shows how rain-gardens/bioswales can convey water away from a site and increase infiltration.

Low Impact Retrofit projects are defined as landscape features which use green infrastructure principles and ideas to manage stormwater within a confined urban space. Low Impact Retrofits are intended to address NPS pollution by capturing and treating stormwater on-site. The use of LIR can effectively reduce NPS pollution loading on receiving waters. Nearly all components of an urban environment have the potential to incorporate LIR projects, while the selection of appropriate and effective practices depends on the variety of site-specific factors. There are two major ways in which to deal with storm water, 1) Capture rain fall (e.g. green roofs) or 2) Capture runoff (e.g. rain gardens) or other practices that infiltrate runoff.

Low Impact Retrofit features can be integrated into rooftops, streetscapes, parking lots, driveways, sidewalks, medians, and open spaces of residential, commercial, industrial, and civic land uses. Existing urban stormwater conveyance and landscape features present opportunities to direct runoff into LIR areas for storage, infiltration, and treatment. Using LIR, it becomes possible to reduce pollution loads on receiving waters and reduce problems associated with peak runoff volumes during rainfall events. HOK is promoting LIR within the urban environment as a vehicle to capture pollutants before they enter into local receiving waters.

Please click here to download the Urban Sub-Basin ActionPlan. (9.34MB PDF format)