Responses of Physico-chemical Variables to Hypolimnetic Aeration in Lake Naukuchiyatal, Central Himalaya, India

Abstract

The effect of hypolimnetic aeration on the water quality of Lake Naukuchiyatal , Central Himalaya was studied during 2017-2018 with the objective of determining the changes in physico-chemical variables of the lake due to aeration. It was noticed that aeration destroyed the thermal stratification and changed the anoxic hypolimnion into oxic zone. The pattern of clinograde distribution of oxygen during pre – aeration, was altered during aeration. The dissolved oxygen was distributed throughout the water column. As a result of aeration, the secchi disc transparency was increased considerably while the hydrogen ion concentration declined significantly. The BOD and the concentration of free carbon dioxide got reduced as a result of aeration. The concentrations of phosphate - phosphorus and nitrate - nitrogen were increased while the concentration of ammonium nitrogen and nitrite nitrogen were dropped. The N:P ratio was also reduced during aeration as compared to unaerated time.