On the use of monitoring data of neighboring river in physical habitat simulation

Sung-Uk Choi, Byungwoong Choi

Tuesday 30 june 2015

15:20 - 15:35h at Amazon (level 1)

Themes: (T) Hydro-environment, (ST) Ecohydraulics and ecohydrology

Parallel session: 6G. Environment - Ecosystem

The physical habitat simulation is a useful tool to evaluate the impact of river improvement or restoration on the river ecosystem before the river works. However, the simulation heavily depends on the monitoring data of the target species. In general, in case when the data are not present nor sufficient, the monitoring data of neighboring streams are to be used. This happens frequently in reality. However, for streams in similar watersheds, the pattern (or distribution) of the monitoring data can differ greatly. Therefore, the transferability of the monitoring data should be assessed a priori if the data of neighboring streams have to be used. This study investigated the impact of using the monitoring data of neighboring streams and assessed the transferability of the data to the study area for the physical habitat simulation. A 2.5 km long reach located downstream of a dam in the Dal River, Korea was selected as a study reach. Zacco platypus was found to be a dominant species in the study area. For the physical habitat simulation, CCHE2D model and Genetic Expression Programming model were used for hydraulic and habitat simulations, respectively. Different datasets collected in three neighbouring streams were used to predict the composite suitability index. The datasets include the monitoring data in the Chogang Stream, the Geum River, and the Hongcheon River, all of which are located closely to the Dal River. The distribution of the physical habitat variables in the dataset of the Chogang Stream appeared to be similar to that in the dataset of the Dal River. The distribution of the composite suitability index predicted using the neighboring stream was compared with that predicted using the monitoring data in the Dal River. The impact of using the neighboring data was assessed by the mean average percentage error. The error ranged from 28.47 – 98.38%. The principal component analysis was also carried out to investigate the transferability of the dataset to the neighboring stream. It was revealed that the connectivity of the dataset of the Chogang Stream is most similar to that of the Dal River. Then, the Geum River and the Hongcheon River follows.