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Design and Evaluation of Precision Vegetative Buffer Strips as Sustainable Conservation Management Practice to Control Non-Point Source Pollution of Hawaiian Watersheds


This project is designed to achieve research, education and extension oriented goals of USDA and CSREES. Overall goal of the proposed project is to evaluate the effectiveness of Variable Buffer Strips (VBS), as soil conservation and pollution prevention techniques, in Hawaii environment and optimize their configuration for use in local conditions. <P>The project aims at accelerating voluntary adoptions of technically effective, sustainable, and economically sound VBS in Hawaii by demonstrating the technique to the respective communities.

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Non-Technical Summary: One of the ways to address water quality problem is the adoption of vegetative buffer strips (VBS), as a watershed management practice, which removes the effects of associated nutrients, sediment, pesticide, or other pollutants prior to their entry into surface waters and ground water recharge areas. The efficiency of VBS is highly dependent on site specific conditions and is closely related to buffer location, width, topography, vegetation type and climatic conditions. In temperate regions, the effectiveness of buffers has been reported on re-establishment of vegetation, sediment, nutrient removal, and increase in organic carbon and supporting soil microbial biomass. There has been a need and knowledge gap regarding the efficiency, optimal design, placement, and vegetation type of VBS best suited to tropical environments. This project aims to design VBS as conservation practice to reduce non-point source pollution in two Hawaiian watersheds; Makaha watershed on the island of Oahu and Hanalei watershed on the island of Kauai. The Makaha watershed has experienced significant land use changes, such as sugarcane cultivation, installation of wells for groundwater pumping, and construction of golf courses, since 1800s. Numerous alien plant species have proliferated throughout the watershed. In the Hanalei watershed, feral ungulates and alien plants are main sources of pollutants. Hanalei River is listed as an impaired water body by Hawaii 2002 Clean Water Act 303d. <P> Approach: Research will be conducted to develop VBS feasible for adoption in local condition, evaluate the VBS to minimize soil and water degradation, and design variable width VBS for Hanalei River and for a range of scenarios with respect to the conditions in the two watersheds. The education goal will be achieved by developing a course module to transfer knowledge regarding tropical watershed and its fluvial system. Feasibility of the proposed conservation technique will be made based on estimating costs and benefits for implementing these techniques through cont benefit analysis. An outreach and extension program will aim to educate land users, students, policy makers, and stakeholders for overall promotion of recommended VBS via workshops, field days, open houses, website, and publication for peer reviewed journals.

Fares, Ali
University of Hawaii
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