Significance of River Channelization and River Corridor for Surface Water in Terms of Pollution Prevention and Ecological Integration: Evidence From the Awetu River, Ethiopia.

There was a strong relationship between rivers and human settlements from the time human beings started a sedentary lifestyle to the present day. This connection between humans and rivers affects river water quality and its ecology, resulting in human health problems. To solve this problem, river channelization and riverside projects are preferred as primary solutions in different countries. The objective of this study is to assess the significance of river channelization and river corridors for surface water quality and ecological integration. Twelve water quality indicators, namely, temperature, electrical conductivity, pH, dissolved oxygen (DO), BOD, COD, nitrate, phosphate, TDS, TSS, and fecal coliform were analyzed. The findings of this study show that the Awetu River channelization contributed to the improvement of water quality, but it is not at the required quality and standard. Many parameters analyzed in the channelized segment of the river were not within the permissible limits of the WHO and Ethiopian standards for drinking water as well as the Guideline Surface Water Quality Standards. The average values of the channelized segment for most variables were between those of the two unchannelized segments, indicating a lack of significant change in water quality as a result of the project. A comparison of the water quality after the project with previous data revealed improvements in most of the parameters. The project also significantly contributed to flood risk prevention, solid waste, and bad smell reduction. The results of interviews with local stakeholders also support the results of practical studies. All of them believe that the project contributed to water quality improvement and reduction of related risk. However, most of them (96%) believe it is not sufficient to solve the problems. The lack of emphasis on liquid waste prevention, lack of uniformity in riverside free space, and lack of recording baseline data for the water quality status and composition of the ecological flora and fauna constitute the main feedback of the project.