Assessing the effectiveness of the Drainage System in Kalerwe, Kawempe Division, Kampala

Abstract

Floods are a big problem in the low lying areas of Kampala such as Kalerwe and Bwaise which leads to loss of lives, increases disease incidences and destruction of properties. The effectiveness of the drainage channels to convey water was examined and assessed after a heavy downpour to identify problem channels, the chocked points and the causes of choking, and the GPS coordinates of these points were taken. The coordinates were entered into a google earth map. In addition, the depth and width of the channels causing flooding were measured. Interviews were held with 60 randomly selected residents from Kalerwe to obtain their perceptions of flooding. Results showed that undersized and poorly constructed channels were the major causes of flooding in Kalerwe. These were followed by poor channel maintenance and indiscriminate refuse dumping. Chocked Point B of the channel was causes by increased silt due to delayed desilting and cleaning of the channels, unplanned construction with in the area leaving no space for channel expansion. The width of the channel was 152.3cm and depth 42.6 cm. Chocked Point A of the channel was caused by undersized channel and unplanned construction of structures such as houses which leaves no space for drainage channel expansion. The depth and width of the channel were too small with increased chokings and silt (mud) hence back flow of water. The width of the channel was 167.6cm and the depth 121.9cm. Chocked point C of the channel was caused by small sized channel and Unplanned activities such as Gaulage which reduce the size of channels during the creation of a space for activity operation. Chocking was also caused by indiscriminate refuse dumping in the drainage channel. The width of the channel was 121.9cm and depth 50.9cm. Chocking point D of the channel was caused by undersized channel as compared to the amount of water collected from different places such as Mulago, Kyebando and Nsooba. It was also caused by poor waste disposal in the drainage channel. Poor road construction planning with small sized and shallow pipes than navigate storm water from the village to the main Nsooba channel increase the back flow of water. The width of the channel was 762.2cm and depth 91.44cm. Chocked Point F of the channel was caused by increased dumping of wastes in the drainage channel by the residents of Kalerwe village. Wastes from the village are collected near the channel (Nsooba channel) and not taken away, when it rains, the same wastes get back into the channel resulting into blockage. The width was 213.4cm and depth 91.4cm.