Assessment of drainage capacity of a surface drain in Rajshahi, Bangladesh

The drainage capacity of a community is essential for promoting environmental resilience, effective water management, and fostering a healthy urban lifestyle. The surface drains in Rajshahi City receive a mix of waste, including sanitary wastewater, stormwater runoff, and solid waste from roadsides and households. To improve the drainage facilities of Rajshahi, some new drains have been constructed. This study considered a recently constructed drain in the Rajshahi City Corporation (RCC), running from Talaimari to Chowddopai. The primary objective of this study is to assess the drainage capacity of this drain during both dry and monsoon seasons, ensuring its capability to contain the generated waste. Additionally, the investigation encompasses observing the sludge depth, and clear space of the drain. A field survey was conducted, employing a measuring rod and scale to precisely measure the depth, width, and sludge accumulation. The results show that the total volume of the drainage system is 117670 ft³, while the total volume of solid deposition is 6287.60 ft³. Solid deposition occupies 95% of the entire drainage path, leaving 5% as clear space. The total solid deposition volume represents approximately 5.34% of the total volume of the drainage system (6287.60 ft³ of 117670 ft³). This study revealed that during typical rainfall intensity in Rajshahi City, the portions of drains from Talaimari to Octroimor and from Rajshahi University main gate to Chowddopai have sufficient open space to prevent water overflow, but the capacity of the drains in the portion between Kajla and Rajshahi University main gate is inadequate.