Spatial and Temporal Fluctuations in the Physico-Chemical Limnology of Mangla Dam (Pakistan)

Mangla dam consists of five distinct basins receiving water from two perennial and two non-perennial rivers. Studies were carried out to find spatial and temporal variation in physicochemical characteristics of the surface water in five basins of the dam from January 2009 to December 2010. The result showed that the mean values of temperature, Secchi Depth, pH, Dissolved Oxygen and Conductivity were 22.8 degrees C, 14.5 cm, 7.81, 7.9 mg/L and 441.7 mu S/cm. The mean values for total alkalinity, total hardness and total dissolved solids remained 120.0 mg/L, 195.9 mg/L, and 314.0 mg/L respectively. Mean values for nitrates (2.44 mg/L) resulted in higher phytoplankton count (92/ml) in the dam. In general, the water quality followed a cyclical pattern with summers favoring higher primary productivity. Except for pH and dissolved oxygen, almost all the water quality parameters varied significantly (P<0.0001) among seasons and basins with no interaction amongst them. Spatially, there was more resemblance between Mangla and Khad basins, and Poonch and Jhelum basins Temporally hot season and monsoon show more similar water quality separating them from cold season and post monsoon.