Water: Nonpoint Source Success Stories
Hawaii: Section 319 Success Stories, Vol. III
Friends of He'eia State Park
|Primary Sources of Pollution:|
|erosion from alien coastal plants|
|Primary NPS Pollutants:|
|removal of alien plants|
|planting of native species|
|projected decrease in sediments and nutrients|
Friends of He'eia State Park is a nonprofit educational institution that offers interpretive programs in the sciences and Hawaiian culture. The park sits on an elevated peninsula on the shores of Kaneohe Bay. Bordering the park are a unique fringing reef, a mountain stream, and an ancient Hawaiian fishpond. This project was part of a larger master planning effort to rehabilitate portions of the entire He'eia watershed.
The state's Department of Health has designated Kaneohe Bay a Water Quality Limited Segment because of the nonpoint source pollution, specifically sediments and nutrients. Kaneohe Bay and He'eia Stream are part of Koolaupoko watershed, designated a priority watershed in need of restoration by Hawaii's Unified Watershed Assessment Plan. Alien coastal plants were causing problems by preventing adequate filtering of waters that emanate from the watershed above before they entered the bay.
Replacing alien plants with native species
The major goal of this project was to expand and enhance the He'eia Stream and coastal area by replacing existing alien coastal plants with native strand species. The area was surveyed, and plans were developed for the removal of the alien plants. Two 40-square-foot test plots were identified to be cleared and planted with native species. Some of the trees removed were 60 feet tall with 16-inch diameters. The trees were cut at the top of the prop roots so the remaining roots could serve as traps or filters.
The project was very successful in removing alien flora from the streambanks and in planting native species such as milo, naupaka, kukui, kou and puhala in their place. The native species are expected to provide continuous protection to Kaneohe Bay by filtering the waters that come from the watershed above. Thousands of people from community groups, schools, service clubs, businesses, and prison work teams provided labor for the project.
Benefits to waters and the community
Students and professors from Windward Community College monitored the water quality of He’eia Stream at five sites in the watershed. The community benefited from this project through the many formal presentations made to the public and from the Hawaiian Lecture Series, which focused on the cultural relationship of the land to the sea. The success of this project has given Friends of He’eia State Park a huge boost in their continuing efforts throughout the watershed.The total cost of this project was $155,000; funding included $60,000 in 319 grant funds.
Department of Land and Natural Resources
3060 Elwa Street
Lihue, HI 96766
|Primary Sources of Pollution:|
|Primary NPS Pollutants:|
|dissolved chemical fertilizers|
|high-nutrient-content aquaculture effluents|
|total dissolved solids|
|integration of aquaculture with taro production|
|reduced levels of ammonia, nitrate, phosphate, and BOD|
Both aquaculture and taro production play important roles in the Hawaiian culture but can sometimes result in significant nonpoint source pollution. Puali Stream and Nawiliwili Bay have been particularly affected by agricultural discharges of dissolved chemical fertilizers, high-nutrient-content aquaculture effluents, sediment, total dissolved solids, and pesticides.
Hawaii initiated a 319 project to demonstrate that the integration of aquaculture with taro production systems can significantly reduce nonpoint source water pollution. The goal of the project was to demonstrate that the application of various best management practices (BMPs) to integrated aquaculture (fish)—agriculture (taro) production systems can result in significant ecological and economic advantages, including, ultimately, the reduction of nonpoint source pollution. Equally important was the goal that the project result in the improvement of the social and economic conditions of taro growers and aquaculturists throughout the state.
New approaches to production
The project involved stocking four pairs of fish tanks with both tilapia and Chinese catfish. Each taro treatment then received the effluent from two fish tanks. Each pair of tanks that discharged into each loi (pondfield) was integrated with four treatment taro pondfields planted with lehua maoli, which then drained into adjacent fields planted with bun long. Two taro controls were integrated with, and discharged into, a wastewater polyculture pond. One was solarized and one was not. The polyculture pond was stocked with fish, taro, and aquatic plants, dependent on waste products from the two controls for their nutritional needs. The system was expected to control eutrophication, recycle organic and inorganic wastes, decrease soil erosion, and abate water pollution.
Quantitative water quality data were collected bimonthly with the use of a Hydrolab and other water quality testing equipment to monitor the following parameters: dissolved oxygen, percent saturation, pH, conductivity, temperature, turbidity, total dissolved solids, total nitrate, total phosphate, total ammonia, and biological oxygen demand (BOD). The purpose of the monitoring was to assess which BMPs and integrated methods are most effective as pollution abatement techniques.
Increased water quality without affecting crop yieldsThis project was successful in demonstrating that the traditional Hawaiian cultural practice of taro production can efficiently meet today's standards of water quality without affecting taro yield. Although the growth rate of the tilapia and Chinese catfish were considered relatively slow, it must be considered that two crops (fish and taro) are being grown and the goal is to optimize the production of both while at the same time protecting the quality of receiving waters. The taro functioned well as a "biofilter" to recover nutrients in aquaculture effluent. Overall levels of ammonia, nitrate, phosphate, and BOD were significantly reduced after the aquaculture effluent flowed through the taro loi.