River Recreational Activity Vulnerability Assessment and the Hydraulic Index Proposal

In this study, a vulnerability index and hydraulic index for recreational activities were developed for assessments in riverside areas to provide water quality and hydraulic information to the public. These novel indices consist of several river recreation activities such as swimming, water skiing, canoeing, etc., and are calculated using hydraulic information. The hydraulic information is integrated with fuzzy synthetic evaluation, with parameters such as velocity, water surface elevation, and water surface width. Also, a water quality index was created using information integrated with parameters such as DO, pH, and chlorophyll a, and then these parameters were combined into the vulnerability index. The proposed vulnerability index and hydraulic index were applied to the Nakdong River, downstream of a large weir. The hydraulic index was also combined with the results from a two-dimensional flow model for the spatial representation of the index for the categorization of safe recreational acceptability levels in the river. The results showed that the calculated index was sufficient to reflect changes in the hydraulic parameters, shown with spatial data, with comparisons to the index calculation from the gauge site measured data, with differences ranging from 0.8% to 6.5%.