The changing water quality of lakes—a case study of Dal Lake, Kashmir Valley

Lakes throughout the globe have been gravely altered or degraded at a pace much more significant than their restoration. In the heart of Srinagar, the summer capital of Jammu and Kashmir, Dal Lake, has witnessed extreme loss in water quality during the last four decades because of anthropogenic pressures. The lake is unique in that over 50,000 people inhabit the lake itself in houseboats, dongas, or islands within the lake. These people derive their livelihood from the lake in terms of tourism, agriculture, fishing, and vegetable farming. The countless ways people use the lake have led to an extreme load of pollution in the lake. Encroachment in and around the lake has led to the loss of volume of water in the lake and consequently increased the concentration of pollutants. Discharge of untreated sewage, agricultural runoff, and sediments from adjoining catchments have further degraded the lake water quality. The changes in water quality are clear from the physio-chemical properties of the lake waters. While transparency and dissolved oxygen in the lake have decreased drastically during the last 40 years, the concentration of harmful substances like phosphates, nitrates, and chlorides has increased. The hardness of water has also increased due to higher levels of carbonates and bicarbonates in the lake. This paper details the changes in the water quality of Dal Lake over the recent past. The paper analyses the strategies that can be implemented to manage the lake and restore its quality if appropriately implemented.