Envir. Sound Approaches for Stormwater Management on Pacific Island Nations

摘要

This paper and presentation will focus on the unique stormwater management issues facing Pacific Island nations (e.g. highly erodable soils, severe precipitation events, dense and varied land use, public recreation in receiving waters, and sensitive benthic environments) and present environmentally sound and sustainable technologies to address these issues. The development of the Stormwater Management Plan (SWMP) for the Garapan drainage on the Island of Saipan, Commonwealth of Northern Mariana Islands (CNMI) will be used as a case study for the presentation. We will present how solving these challenges lead to the development of environmentally sound, sustainable and effective solutions that can be used in any environment. The CNMI Division of Environmental Quality (DEQ) requested Winzler & Kelly prepare a conceptual stormwater management plan of the Garapan II drainage. The Garapan II drainage, which contains the heavily developed Garapan business district area of Saipan, is being used as a test region, and future, similar studies hope to build on the methodologies developed for this drainage for further implementation on Saipan. This drainage also serves as a good model for many of the stormwater issues facing other communities. The watershed contains widely varied land-use, from heavily vegetated steeper slopes in the upper watershed, with homesteads and small agricultural plots, to heavily developed and paved hotel and industrial areas on the coast, to the sensitive and fragile benthic environment where the drainage discharges. Surface water sampling results show impacts from fecal coliform, nitrates, phosphates, and turbidity, many of the same constituents that plague numerous island watersheds. One of the main goals of the Garapan SWMP, consistent with most island nations, is to protect the surrounding coral reef and benthic community. Another goal is to improve the water quality to prevent public beach closures which affect the local businesses that rely on tourism. The presentation will discuss the development of the SWMP and selection of the BMPs. It will also present the importance of, and offer suggestions for, obtaining positive public participation and stakeholder involvement to formulate solutions that are not just technically feasible, but that have the support of stakeholders as well.