Author(s): Masayuki Nitta; Muneyuki Aoki; Mitsuru Ohira

Linked Author(s): Muneyuki AOKI, Masayuki Nitta

Keywords: Cultural ecosystem services; River environments; RHS and HQA; Recreational use; Environmental assessment

Abstract: Assessment of aquatic habitat and recreational use is required toward managing cultural ecosystem services in rivers. This study aimed to evaluate the river environments from viewpoints of both aquatic habitat and the potential for recreational use. RHS and HQA were applied in the Koaze River in the Arakawa River system, Japan, and HQA score was calculated. Recreational use potentials were evaluated assuming child use from the viewpoints of water quality, biotic conditions and hydraulic characteristics of the sites, and child-use potentials (CUP) were calculated. As the results, HQA score showed the greatest variation in flow types among the evaluation items. CUP score showed a large variation in hydraulics and organisms among the variables. Regression analysis showed no correlation between HQA and CUP scores (R2=0.0005). This was because the HQA emphasized the degree of development of reach structure (i. e. environmental heterogeneity derived from differences among units), whereas the CUP was based on a certain environmental range and specific fish species. However, higher scored reaches by HQA and CUP, commonly had high values of channel morphology, riverbed materials, and vegetation cover. This indicated that the developed channel morphology (high HQA) included slow and shallow flow environments and related richness of aquatic organism (high CUP). The representative reach of such environment has a gravel bar which contributes to channel meandering and creating natural bank and vegetation. Therefore, gravel bar induced channel morphology development can be a key for habitat formation and recreational use.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0298-cd

Year: 2023