Crack in Vamanapuram River Salt Barrier Wall Puts Drinking Water Supply at Risk
A concerning crack has developed in the critical salt exclusion barrier wall located near the Poovanpara dam on the Vamanapuram River, raising significant alarms over the safety and reliability of drinking water supply to lakhs of residents in Chirayinkeezhu and Varkala taluks. This issue emerges as river flow levels are already declining in anticipation of the upcoming summer season, compounding the potential crisis.
Damage Near Intake Points and Lack of Repairs
The damage has been specifically reported on the northern side of the protection wall, dangerously close to the intake points of several key drinking water projects. Officials have confirmed that no repair work has been carried out so far, which heightens fears of erosion and possible weakening of the riverbank. This risk is particularly acute if water levels rise or if there are changes in flow patterns, which could exacerbate the structural integrity of the area.
Purpose of the Salt Exclusion Wall and Risks of Saline Intrusion
The salt exclusion wall was originally constructed to serve a vital purpose: preventing seawater intrusion and protecting the downstream stretch of the Vamanapuram River. This river is tidal in nature due to its connection with the Anchuthengu backwaters. During high tide and the summer months, saline water typically moves upstream, increasing salinity levels and accelerating riverbank erosion. Sources within the Kerala Water Authority (KWA) have warned that damage to this wall could allow saline water to enter the freshwater stretch of the river.
They further cautioned that an increase in salinity could affect the stability of the dam and the intake points. This scenario poses a serious threat of disrupting drinking water supply during peak summer, a time when river flow is already at its lowest, making the situation even more precarious.
Impact on Water Supply and Temporary Measures
The Poovanpara dam is a crucial source of drinking water, supplying more than 2.5 lakh domestic connections across several panchayats in Chirayinkeezhu and Varkala taluks. Collectively, these schemes draw over three crore litres of water daily from the Vamanapuram River. Officials have noted that river flow has already reduced significantly, underscoring the urgency of addressing the wall damage.
As a temporary measure to mitigate the situation, steps have been taken to increase the height of the dam using soil-filled bags and tarpaulin sheets. This practice is followed annually to retain water for drinking purposes, but it is only a stopgap solution that does not address the underlying structural issue with the salt exclusion wall.
History of the Crack and Delayed Repairs
An assistant executive engineer with the minor irrigation department revealed that the crack was first noticed as far back as 2019. Although a contractor was engaged to carry out repairs at that time, the work was not completed, and the contract was later terminated. The official stated that the department would now have to retender the work, and the timeline for starting repairs could not be specified at present. This delay highlights ongoing challenges in infrastructure maintenance and the potential for prolonged risks to water security.
