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| American Samoa Water Quality Projects |
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To help prevent watershed degradation and to assess restorative measures, a rapid, accurate, cost-effective water quality monitoring program is essential. |
| Multimetric indices of biotic integrity (IBI) are an effective tool used worldwide and are currently being applied to streams in American Samoa. ASCC Water Quality research program manages the project and all laboratory work is conducted at ASCC. |
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Project background
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| An unchecked population growth rate of 3.7%, coupled with periodic El Niño-induced droughts, make American Samoa’s reliance on an adequate, safe drinking water supply increasingly important. While little can be done to increase supply, much can be done to ensure that existing water resources for the territory’s rural communities are optimally available. |
| Clean water is the product of a healthy watershed. Its degradation usually begins where human activity, particularly agriculture, alters the plant cover and increases watershed discharge. Change in habitat structure, combined with alterations of the stream channel, diminish the quality of water flowing in the channel as well as the structure and dynamics of the channel. These, in turn, may disrupt biotic interactions in the stream and its adjacent riparian corridor. |
| To help prevent watershed degradation and to assess restorative measures, a rapid, accurate, cost-effective water quality monitoring program is essential. Multimetric indices of biotic integrity (IBI) meet this need. |
| A metric is a measure of a biological attribute, eg., number of species, that reflects a specific and consistent response to human activities. An IBI produces a score, based on several metrics, for each sample site. This score allows a comparison of environmental conditions at one site with conditions at other sites. Scores can be monitored at a single site over time or at several sites within a carefully defined geographical area for which the metrics and the scoring criteria have been developed. |
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| As mandated by The Clean Water Action Plan of 1998, the American Samoa Environmental Protection Agency assessed 38 watersheds of the territory’s five inhabited islands and assigned each to one of three categories (American Samoa EPA 1998). For the main island, Tutuila, 30 of 163 principal watersheds were categorized as follows: |
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I. In need of restoration (5)
II. Meeting goals but needing action to sustain water quality (24)
III. With pristine or sensitive aquatic conditions (1) |
| Categories were based primarily on land use data and practices, waste disposal practices, and soils information supplemented, where available, by chemical or physical water quality parameters. |
| Owing to expense few parameters were measured, and these were usually unreplicated or outdated for most streams. |
| Biological assessments, on the other hand, can economically diagnose chemical, physical, and biological impacts as well as their cumulative effects. Coupled with specific chemical toxicity testing, they can serve many kinds of environmental and regulatory programs. |
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