Trophic status of Dal Lake, Kashmir, India

The study was conducted in the Dal lake, which is situated on the northeast of Srinagar at latitude 340,07/ N and longitude 740, 52/ E on the right bank of river Jhelum. Four water- sampling sites (Viz: Hazratbal, Nishat, Nehru park and Nigeen) were selected for study. The water samples were analyzed for pH, conductivity, turbidity, dissolved oxygen, chemical oxygen demand, chlorine, hardness, total alkalinity, ammonium nitrogen, sulphate and phosphorus on fortnightly basis for six months. The results showed that the maximum value of pH was observed at Nehru Park (DD3) 10.66±0.21 mg/1 and the minimum 8.14±0.01 mg/1 at Telbal Nallah (DH4) respectively. The conductivity value, an indication of total nutrient concentration, was notably higher at various sites of Dal Lake. The maximum value of conductivity is 426.3±10.12µs/cm and the minimum 186.3±7.11µS/cm at Telbal Nalah (DH4) and near Heemal Hotel (DD2) respectively. The D.O. ranged between 10.31±0.01 mg/l at Centaur hotel (DD4) to 5.0±0.01 mg/1at Telbal nallah (DH4).The turbidity value was recorded to be maximum of 45.02±0.01 at Dhobighat (DH1) and minimum of 1.90±0.00 mg/1 at Central site (DH2). The higher values of C.O.D prevail over the entire lake water, particularly at DH4 of Telbal Nalah 84.33±1.9 mg/1 and the lowest value at DD3 of Nehru park (42.40±6.1 mg/1) respectively. The maximum value of chloride, hardness, total alkalinity, ammonium, nitrogen sulphate and phosphorus was observed at Hazratbal basin. This study has clearly demonstrated that the Hazratbal basin of Dal Lake is highly polluted in comparison to other sites owing to regular addition of urine and human waste dumped into the lake along with run off of chemical fertilizers from the waste drainage basin around it.