Assessing the influence of stream flow and precipitation regimes on water quality of the major inflow stream of Wular Lake in Kashmir Himalaya

Abstract

Wular Lake in the Kashmir Himalayan part of the Indian subcontinent is facing severe eutrophication due to the enhanced nutrient loads from its catchment. For holistic management of this lake, quantifying the nutrient loads from all of its inflow streams is compulsory for establishing a scientific basis for managing its highest loading watersheds. The present work has been carried out in the Sukhnag stream and is one of the major inflow streams of the Wular Lake. The analyses presented hereof are the initial results of the comprehensive assessment taking place in all the other inflow streams of this lake. Here, we present an analysis of the 12-month water quality data of this stream at five different locations, whereof we have estimated the concentration and export coefficients of the nutrients and major ions and their relation with the discharge and precipitation regimes. The results revealed statistically significant relationship of stream flow with ortho-phosphorus, total phosphorus, NO3-N, Ca2+, Na+, total suspended solid (TSS), and total dissolved solid (TDS) and insignificant relationship with NO2-N, NH4-N, organic nitrogen, and total nitrogen. Seasonal variation in nutrient load and export coefficients showed a linear relationship with high concentrations during spring and summer and low concentrations during autumn and winter. Further, the results showed that this stream during the observational period loaded 0.15 × 108 g of ortho-phosphorus, 0.53 × 108 g of total phosphorus, 0.96 × 108 g of NO3-N, 0.05 × 108 g of NO2-N, 0.14 × 108 g of NH4-N, 0.61 × 108 g of organic nitrogen, 1.75 × 108 g of total nitrogen, 22.9 × 108 g of Cl−, 60.4 × 108 g of Ca2+, 13.4 × 108 g of Mg2+, 20.7 × 108 g of Na+, 4.88 × 108 g of K+, 112.2 × 108 g of TSS, and 435.5 × 108 g of TDS into the Wular Lake. Seasonally, spring contributed the maximum average loads of about 62.18 % followed by summer (18.86 %) while as winter and autumn contributed about 9.61 and 9.35 %, respectively. This analysis on the Sukhnag stream is the first and key step toward a complete nutrient load analysis of all the inflow streams of the Wular Lake.