Evaluation of Seasonal Variations and Water Quality Index at Seti River, Pokhara

Abstract

Purpose: This research investigates the seasonal variations of the Seti River during the dry and wet seasons.
Methods: Water samples were collected from two sample locations (n = 3) between April 2024 and July 2024 representing both wet and dry seasonal conditions. The physiochemical parameters analyzed were pH, Total Suspended Solids, Electric Conductivity, Dissolved Oxygen, Phosphate, Nitrate, Ammonia, Biochemical Oxygen Demand, and Total Hardness using American Public Health Association (APHA) methods. Water Quality Index (WQI) was determined to evaluate the status of water quality during the dry and wet seasons.
Results: Concentration of various physiochemical parameters were analyzed and significant differences in all physiochemical parameters were observed. Five parameters (pH, Total suspended solids, Total hardness as CaCO3, Ammonia and Dissolved oxygen) showed their maximum level during wet season. Other parameters (Electric conductivity, Nitrate, Phosphates and Biochemical oxygen demand) showed their highest value during dry season. The calculated WQI for Hemja and Patneri during dry and wet seasons were 66.1, 44.9, 84.5 and 77.6, respectively.
Conclusion: The analysis of the results indicates a gradual decline in the quality of Seti river. It is worsened, mainly during the rainy season as the river receives increased loads of contaminants including agricultural and surface runoff.