Seasonal Changes in Water Quality Parameters and Sediment Nutrients in Jagadishpur Reservoir, a Ramsar Site in Nepal

Abstract

Physical and chemical characteristics of waters in reservoirs are influenced by seasonal fluctuations in water and also by agricultural runoff. Such fluctuations are more frequent in Jagadishpur reservoir where rain events are strongly seasonal. To carry out the study, water samples were collected from six sites where as the soil samples were taken from four sites in four seasons (winter, spring, monsoon and autumn) in 2006. The soil and water nutrients both varied seasonally affecting the productivity of the reservoir. The productivity of the reservoir was maximum in monsoon and minimum in autumn. The release of phosphorus and nitrogen from the lake sediment to water column plays a key role in determining the nutrient level in reservoirs. The reservoir was found to be polytrophic: eutrophic on the basis of transparency and total nitrogen and hypereutrophic on the basis of phosphate concentration.

Key words: productivity; polytrophic; eutrophic; hypereutrophic

DOI: 10.3126/njst.v9i0.3180

Nepal Journal of Science and Technology 9 (2008) 149-156