Managing Hawaii's Watersheds

The Hawaiian ahupua'a system of managing the resources of lands and coastal waters is briefly described

Livestock Producer’s Nutrient Management Planner Guidebook: A Waste Management Planning Guide for Pacific Island Livestock Producers

This Livestock Producer’s Nutrient Management Planner provides you, the livestock producer, with help in developing an animal waste management plan for your farm. The plan will be unique to each individual farm due to differences in the types of animals you raise, where your farm is located, and how you manage your operation. This workbook is designed to provide the basics on laws and regulations, the concept of nutrient flow through your farm, a series of worksheets to establish the status of your operation, and a guide to developing your farm’s nutrient management plan

Water issues in Hawaii: public attitudes in 2004 and 2010

This report examines Hawai‘i residents' awareness of, attitudes about, and actions taken concerning water quality. "Water quality" is a measure of the suitability of water for a particular use, such as drinking, recreation, agricultural irrigation, or protection and maintenance of aquatic life

Sediment Transport, and Effects of Feral Pig (Sus scrofa) Exclusion in a Forested Hawaiian Watershed.

v. ill. 23 cm.QuarterlyBrowsing and trampling by nonnative feral pigs (Sus scrofa) negatively impact native flora and fauna in forested ecosystems and cause soil compaction. However, their impact on runoff and erosion is largely unknown. This study addressed this knowledge gap by investigating effects of feral pigs on runoff volume and total suspended solids (TSS) in runoff from the upper forested area of a Hawaiian watershed. Correlations between TSS, runoff, and other environmental variables were also examined. Runoff was collected monthly after 11 individual storm events from June 2008 to April 2009 at seven sites in the Mänoa watershed on the island of O‘ahu. Each site consisted of paired runoff plots (5.04 m2) with one plot located inside a fenced pig exclosure (exclosures 1 yr old at study initiation) and the other located in an adjacent area open to feral pigs. Forest composition and structure (stem density, stand basal area, and seedling/ sapling counts) were quantified at each site. Soil moisture, throughfall, runoff volume, and TSS in runoff were sampled for each storm event. The seven sites varied considerably in terms of forest structure, with stem densities ranging from 1,500 to 9,000 stems ha-1 and basal areas ranging from 20 to 132 m2 ha-1. Vegetation at all sites was dominated by nonnative species. Runoff volumes from fenced and unfenced plots were highly variable, ranging from 128 liters. TSS levels in runoff ranged from <0.01 to 7.05 g liter-1. TSS levels were generally higher in wet-season months, but this pattern was not consistent across all sites. TSS in runoff was significantly correlated with throughfall, soil moisture, and coarse woody debris cover. Although pig exclusion did not reduce TSS, significant reductions in runoff volume from pig exclusion plots were observed at one site, and two other sites showed a similar trend. Longer-term studies may reveal stronger or more consistent impacts of feral pigs. Using paired fenced versus unfenced runoff plots to study erosion impacts of feral pigs is a novel approach, and results from this study will help forest managers better understand and manage runoff and erosion dynamics

Comparative phosphorus sorption by marine sediments and agricultural soils in a tropical environment

The influence of soil phosphorus (P) sources on P sorption characteristics of marine sediments was investigated for Pearl Harbor and off shore Molokai in Hawaii. Estuary sediments were sampled in seven locations; these represented different soils and on-shore activities. The soil samples included nine major soils that contributed sediment to the Harbor and coastal sediments near the island of Molokai. Sediment and soil samples were equilibrated for 6 days in 0.01 M CaCl2 solution and synthetic seawater containing differing amounts of P. Phosphorus sorption curves were constructed. The equilibrated solution P, with no P added, ranged from 0.01 to 0.2 mg -1; P sorption by sediments at standard solution concentration 0.2 mg L-1, ranged from 0 to 230 mg kg-1. Sediment P sorption corresponded closely with soil sorption characteristics. Soils contributing sediments to the west reach of Pearl Harbor are highly weathered Oxisols with high standard P sorption values while those in the southeast of the Harbor were Vertisols and Mollisols which sorb little P. The influence of source materials on sediment P sorption was also observed for off-shore sediments near Molokai. Sediments serve as both source and sink for P in Pearl Harbor and in this role can be a stabilizing influence on P concentration in the water column. Phosphorus sorption curves in conjunction with water quality data can help to understand P dynamics between sediments and the water column and help evaluate concerns about P loading to a water body. For Pearl Harbor, solution P in equilibrium with sediments from the Lochs was 0.021 mg L-1; a value unlikely to produce an algal bloom. (Measured total P in the water columns (mean) was 0.060.). Copyright © Taylor & Francis Group, LLC

Priority Drinking Water Issues in Hawaii

Information that can be used to develop relevant drinking water Extension programs for Hawaii residents was collected in a 2010 survey. The major findings were: (1) over 85% of survey respondents feel that their home drinking water is safe for consumption, (2) 84% obtain their drinking water from public water suppliers while 12.2% rely on bottled water, (3) 72% are satisfied with their drinking water, and (4) drinking water quality is not uniform across the state as significant numbers of Maui residents either use bottled water or are dissatisfied with one of more aspects of their potable water