Author(s): Bin Li; Joeselle Serrana; Kozo Watanabe
Linked Author(s):
Keywords: Dam; Gravel bar; Macroinvertebrate; Water quality; River restoration
Abstract: Dam construction obstructed migration pathways of organism and trapped sediment which brought many adverse effect on the ecosystem downstream the dam. Artificial gravel bars was one of the most widely applied restoration activities to improve degraded waterways. In order to evaluate the restoration performance of artificial gravel bars, we investigate the macroinvertebrate community and biodiversity using Throughput Sequencing (HTS) technologies and assess the water quality purification function of the artificial gravel bars by comparing water quality in bar head and tail in Trinity River downstream of the Lewiston Dam in August 2017. Six gravel bars in the main channel downstream of the Trinity River were selected. As a basis of comparison, 2 reference free flowing segments in the main channel downstream of the dam, 2 gravel bars and 2 free flowing river segments in a tributary without dam influence were investigated. Overall, DO showed a relative reduction trend from the down-to upwelling zone observed on both gravel bars in the main river channel and reference site although significant difference was only observed on 2 gravel bars from the main channel (i. e. GB01 and GB03). There was no clear difference of conductivity within and against the gravel bars in the main channel except for GB04. Rush Creek (GB07, FF01) showed a significantly high conductivity, while Canyon Creek (GB08, FF02) showed significantly low conductivity compared to the gravel bars in the main river channel (p< 0.05). For the water temperature within the site, significant difference was shown in GB01 and GB02. But tributary sites showed significantly higher water temperature than gravel bars in the main channel (p< 0.05). showed a reduction trend from down-to upwelling for both the main river channel and reference sites except for one free flowing segment in the tributary (Rush creek, FF01). For the AFDM, sites in the tributary showed extremely high value while there was an increasing trend in the gravel bars in main channel. A total of 44genera macroinvertebrate from 35 families were identified. As a preliminary analysis, taxa richness was used to evaluate macroinvertebrate community. Generally, the taxa richness was more or less similar between the down-and upwelling zones except several sites that have distinct habitat types between them (e. g. GB04, GB06). Relatively, the reference sites in the tributary have higher taxa richness.
Year: 2018