Evaluating the influences of bed sediments on pollution status of Chaktai and Rajakhali Canal, an experimental approach

With the ongoing growth of rapid urbanization, likewise surface water in many developing countries, surface water resources in Bangladesh are also being polluted day by day from various anthropogenic sources in terms of water quality. In Chattogram’s urban drainage system, Chaktai and Rajakhali canals, are considered the two most key canals among the thirty-six canals that are mainly pathways the urban drainage discharge into the tidal Karnaphuli river. The purpose of this study was to investigate the contemporary status quo of surface water of the Chaktai and Rajakhali canals and to evaluate the impact of bottom bed materials in reducing pollution levels in context of sustainable urban drainage. Surface water quality for the selected two canals was investigated during the ebb and tide phases measuring the key physical and chemical parameters of water quality. The statistical tool SPSS was used to perform the descriptive statistics, correlation analysis, and the whisker-box plot analysis. Furthermore, the trend analysis was also carried out using the Mann-Kendall test and Sen’s slope estimator. Additionally, the efficacy of nine canal bed prototype configurations (made from locally available materials) was examined in treating water from the common point of two canals. The average value of temperature, pH, TDS, DO, EC, and turbidity was found as 27.63°C, 6.92, 1050.75 mg/L, 1.65 mg/L, 2.30 mS/cm and 250.22 NTU, respectively. The overall pollution status quo for canals is very poor to poor during ebb and tidal period, respectively. The scattered association among parameters studied indicate a rapid monitoring a promise. Although a disperse results in improvement of bed materials is found, the potential influences with bed materials in a combination are found. Among nine physical models tested, a few combination with natural soil, stone, charcoal was seen to play a substantial role in reducing the overall canal water pollution level offering onsite and local treatment.