Mandi: Mandi’s renowned Rewalsar Lake has once again fallen victim to neglect and rapid sedimentation, jeopardizing its once-pristine beauty. In the past decade, the lake has experienced muddy waters, resulting in the unfortunate death of numerous fish due to low oxygen levels. Concerns are now escalating as the water turns murky once more.
To address this issue, a team from the pollution control board recently visited the lake to conduct water tests and assess pollution levels. Initial reports indicate a significantly low dissolved oxygen level of 2.5mg/l, well below the recommended concentration of 5mg/l for aquatic life. Mortality is expected to occur at levels below 2mg/l.
The deteriorating state of Rewalsar Lake has been attributed to various factors, including sedimentation, pollution, sewage flow, unseasonal rains, mud and muck accumulation from connecting rivulets, littering, fish feeding by visitors, excessive weed growth, and the absence of proper channelization of rivulets. These issues were highlighted in a recent news article by TNR, shedding light on the lake’s decline.
Local NGO, Development Action Group (DAG), has been actively involved in year-round lake cleaning efforts. Naresh Kumar Sharma, DAG’s president, expressed frustration with the district administration and the Nagar Panchayat, blaming their indifference for the lake’s worsening condition. Despite requests from the state wetland authority for a detailed conservation and preservation proposal, both departments have neglected their responsibilities. Presently, funds allocated by the authority are solely directed to the forest department for catchment area projects, neglecting the lake itself.
When contacted, Smritika Negi, SDM Balh and Chairman of the Rewalsar Development Committee, confirmed that water samples had been taken and emphasized the need to wait for the report’s findings.
Rewalsar Lake’s struggles are not isolated. Pristine Himalayan lakes face threats from increased sedimentation, ecological degradation, and pollution, primarily due to human interference. A study conducted by the Wadia Institute of Himalayan Geology revealed that Rewalsar Lake experienced the highest sedimentation rate of 3.35 cm/year over the last 50 years compared to other lakes in the northwestern Himalayan region. The study attributed this rapid sedimentation to human activities, such as civil constructions and township growth in the lake’s catchment area.
Scientists concluded that natural parameters like lithology and rainfall were not significant factors in the sedimentation rate. Instead, human interference emerged as the primary cause. The construction of a barricade around the lake after 1995 AD appeared to have reduced sedimentation, but the current rate remains much higher than other lakes in the region. Urgent action is required to address the alarming sedimentation rate and safeguard Rewalsar Lake from further degradation.
The Rewalsar Lake lies within the Siwalik sedimentary basin, surrounded by late-Quaternary deposits prone to weathering and erosion. Consequently, the lithology alone cannot be blamed for the sedimentation issues observed in the lake.
It is imperative that authorities take immediate action to restore and protect the once-pristine Rewalsar Lake, preventing its further decline and preserving its natural beauty for future generations.
