Community watershed management: Does the use of a watershed model affect the process

Nonpoint Source Pollution (NPS) is recognized as a leading cause of water pollution in the United States. The purpose of this research was to introduce a watershed model, N-SPECT (Nonpoint Source Pollution and Erosion Comparison Tool), to estimate NPS given changes in land use and land cover. The model was evaluated by the community to determine its efficacy as an instrument for change in public behavior for community watershed management. The N-SPECT model was applied to the Hilo Bay watershed in Hilo, Hawaii and analyzed for its ability to simulate runoff and pollutant concentration. The calibrated model was able to predict runoff volume on an average annual basis within a 10% error rate from observed runoff. Pollutant concentration error rates varied by site and pollutant. There were noted limitations to the calibration process and validation results highlight these difficulties. Scenarios representing hypothetical changes in land use were derived using the model then incorporated into a multi-media presentation delivered to community groups who were asked to evaluate the N-SPECT tool by completing a survey questionnaire. Results of these surveys indicated that 44%--81% of participants believed the model increased their knowledge of factors affecting water quality, found the model to be a useful tool in water quality management, would use the model as a conflict resolution tool in environmental disputes, and felt access to a tool like this would motivate them to increase their participation in the watershed and community planning processes. There were distinct differences in responses for persons raised in Hawaii, as compared to those who are not, for four key survey questions evaluating the model. The difference in response underscores the need for a clear understanding of the community and how to apply tools in a way that increases their confidence and participation. A model such as N-SPECT contributes to the decision-making process of watershed management by providing community stakeholders with an informative tool for educating the community on how their actions affect water quality and offers them a scientifically-based tool to use when considering different land use change options in their regional planning efforts.