D. S. Janik, Oahu County Water Quality Extension Agent, Hawaii Cooperative Extension Service, College of Tropical Agriculture and Human Resources (USDA Cooperating), University of Hawaii at Manoa, Hawaii.
The Kaiaka-Waialua Bay News is the official newsletter of the USDA Kaiaka-Waialua By Hydrologic Unit Area Project. The purpose of the Kaiaka-Waialua Bay News is to provide you with updates on projects, upcoming events, and research information. The Kaiaka-Waialua Bay News will also provide soil and water conservation ideas and measures, educational resources, and strategies for resource management and protection.
Kaiaka-Waialua Bay News is published quarterly by Hawaii Cooperative Extension Service with participation from USDA Soil Conservation Service, USDA Agricultural Stabilization and Conservation Service, and the West Oahu Soil and Water Conservation District. Distributed in cooperation with the U. S. Department of Agriculture in furtherance of the Acts of Congress of May 8 and June 30, 1914. Cooperative Extension Work in Agriculture and Home Economics, Noel P. Kefford, Director and Dean, Hawaii cooperative Extension Service, College of Tropical Agriculture, University of Hawaii at Manoa, Honolulu, HI 96822 USA. To cite this article use: Janik, D. S. Our Ecological Health. Kaiaka-Waialua Bay News 93 Dec (2) 4: 1-3.
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The Kaiaka-Waialua Hydrologic Unit Area (KW HUA) is the only Hawaiian watershed selected by the United States Department of Agriculture (USDA) to receive federal funding to protect surface, ground and coastal waters from nonpoint source (NPS) pollution. Since 1991, more than 30 federal, state, county and private agencies and land users have worked together to reduce land erosion, control the use of chemicals that can contaminate surface and groundwater, identify and assess the impact of NPS contaminants, and inform, empower and enlist the participation of the community. Now in its fourth of five years, it seems a fitting time to ask how is our ecological health these days?
Hawaii Environmental Risk Ranking (HERR) Study
In a September 1992 HERR Executive Summary Report, the Hawaii Association of Environmental Professionals identified aquatic ecosystems (streams, estuaries, wetlands, coastlines and reefs) and some terrestrial ecosystems (forests and grasslands) at high risk of being damaged by NPS contaminants (see Land at Greater Risk of "Illness" than People KW HUA News Vol 2 #2). NPS contaminants include sediment from road building/construction sites, crops, and eroding stream banks; fertilizers, herbicides and insecticides from agricultural/ residential areas and golf courses; and oil, grease, and toxic chemicals from urban runoff. Decreasing diversity of biological life (biodiversity) is an especially serious and late sign of ecological damage in the Waianae and Koolau low forest terrestrial ecosystems. KW HUA aquatic ecosystems were not evaluated.
State of the Water
Dr. Dan Janik, Extension Agent in Water Quality for KW HUA, recently briefed Wahiawa Lion's Club, and Northshore and Wahiawa Neighborhood Boards on the state of KW HUA aquatic ecosystems. According to Dr. Janik, our streams are commonly diverted near their mountain source. "Dry" streams recharge with groundwater and surface runoff, and can carry heavy sediment loads during rains. In a recent study. Dr. Gordon Dugan of the University of Hawaii Manoa Water Resources Research Center (WRRC) confirmed heavy KW HUA stream sediment loads after rain (and an absence of expected inorganic and organic chemical contaminants). Accord- ing to DOH, leptospirosis and giardiasis bacteria are considered endemic (always present) in streams.
KW HUA estuaries are rechannelled and largely disconnected from wetlands, many of which have been filled for further agricultural or urban development. Stream sediments cannot settle out and are instead deposited directly into bays. Preliminary data indicate that nutrients and contaminants are present, and that sediment may be toxic. "By binding onto sediment, contaminants may exert effects yet escape detection," said Dr. Janik.
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According to the 1993 DOH "Hawaii Ambient Water Quality Monitoring Program Report (WQM)" fecal bacteria are a continuing problem. Sources are not identified. Leptospirosis and giardiasis bacteria are [once again]considered by DOH to be endemic.
WQM turbidity levels in both bays are hundreds to millions of times higher than allowed. Turbidity, to some extent, reflects sediment loads. Dissolved oxygen (DO) levels have slowly diminished since 1990. DO is necessary for marine animals to "breathe." Nutrients like nitrate and phosphorus continue to exceed DOH criteria. Alpha-chlorophyll (a measure of algal presence or "bloom") is decreasing but still exceeds criteria by hundreds of millions of times. Proprietary tests using bacteria to ascertain toxicity indicate that water and sediment may be toxic to some species. DOH has designated both bays "Water Quality Limited Segments (WQLS)." WQLS's do not meet and are considered not likely to meet minimum water quality criteria.
Groundwater from 11 wells within KW HUA have been found to contain identifiable contaminants (see And More on Groundwater Contamination, KW HUA News Vol 2 #2). At four
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sites, water would require treatment before drinking. According to DOH, our drinking water is and is expected to continue to be safe. Some contaminants are reportedly no longer used, while others, like nitrogen fertilizers, are still in use. The extent, progression and source(s) of most of groundwater contaminants are still not well known. Their effects on animals, plants, soil microbiology, ecology and receiving waters within the HUA have yet to be studied.
Humans versus Nature
KW HUA is subject to intermittent heavy rainfall and tidal action making it difficult to separate out the effects of human versus nature. However, Hurricane Iniki recently provided some insight Hawaii Department of Land and Natural Resources (DLNR) recently reported a study of Iniki's impact on Big Island O'opu. The O'opu is a fish native to KW HUA streams and estuaries, and a candidate for the federal endangered species list.
After Iniki, selected stream beds experienced severe erosion and loss of biological diversity, not dissimilar to KW HUA streams during heavy rains, with disruption of O'opu behavior and reproduction. Within 6 months, the O'opu's were back to normal.
"This proves that streams are very resilient. They can take natural changes, even disasters, and rebound. It is the man-made changes that really threaten the health of stream ecosystems," DLNR Aquatic Biologist Robert Nishimoto said. "Erosion, grading, siltation, leaching, nonpoint-source pollution - these are the real dangers to our aquatic environment"
DLNR Aquatic Biologist Don Heacock made similar observations regarding Kauai's post-Iniki coral reef ecology. Very shallow reef ecosystems showed initial impacts. For several months Poipu was ringed with dark brown, turbid water. But the water cleared up and marine life returned within months. Persisting effects were due to NPS contamination from renewed human activities.
Nishimoto and Heacock hypothesize that over millennia, Hawaiian ecosystems have developed effective ways to cope with natural events. From an ecological perspective, human-related NPS effects are less intense, but unremitting and compound rapidly making it difficult for ecosystems to readjust.
The KW HUA Project comes at a critical time for this watershed. Issues such as diversification of agriculture, development of agricultural and remaining wet lands, conversion from cesspool/septic systems to centralized wastewater treatment facilities, storm water desedimentation and recycling all directly impact water quality. "We've come a long, long way the last 20 years," agree Bernice Arakawa and George Nakasato, current and former administrators for UHM Oahu County Cooperative Extension Service respectively. "More and more people are becoming aware of the importance of water quality in their daily lives."
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