Floods persist despite costly cleanup efforts

Thiruvananthapuram: One reason for flooding in Thiruvananthapuram is the overflowing of canals clogged with waste, delta formation, and shrubs and trees. Although over Rs 4.3 crore has been spent in the past five years cleaning five waterbodies (Pazhavangadi thodu, Ulloor thodu, Thekkanakkara canal, Killi river, and Karamana river), the city continues to experience floods during rain.According to an RTI reply from the department of irrigation, the highest amount was spent on Killi river (Rs 1.84 crore) and Pazhavangadi thodu (Rs 1 crore).
Following flooding in the city in 2021, irrigation department prepared an initial study report on flood mitigation. The study identified around 500 vulnerable points in the waterbodies which required immediate attention. A data bank was created on these points and is being reviewed. Additional chief secretary ( water resources) had directed that each waterbody has to be assigned an officer to identify bottleneck points.
As per the report, frequent cleaning to avoid delta formation inside the waterbodies, identifying waste dumping areas for regular cleaning, steps to be taken by corporation to prevent further dumping of wastes into waterbodies, preventing growth of vegetation inside the waterbody were proposed as steps to be taken on a war footing. Installation of CCTVs and fences were also recommended.
The report noted that the most severe and frequent flooding in the city occurs at Thampanoor, East Fort, Uppidamoodu and Kannammoola. The flooding in these areas occurs three to six times during monsoon. The average water depth is 0.6m to 1.2m and persists for two to 24 hours in the central part and three to four days in the southern part of the city. The drainage network of the city consists of two major rivers namely Karamana and Killi, a few canals, their feeders and lakes, the project report said.
The phase 1 covering various waterbodies was expected to be completed in three months. Emergency side protection works would be undertaken in phase 2. Karamana river covers the longest distance (21km through the city). The project summary on Karamana river shows that the low bund height at various locations along the river causes flooding in nearby areas during monsoon. The damaged bunds which are about to breach may cause bund failure and damage to life and property of people and the formation of deltas due to siltation affects the smooth flow of river course, the report pointed out.