Evaluation of the Limnological Status of Beeshazar Lake, a Ramsar Site in Central Nepal

摘要

Lack of monitoring and implementation of appropriate management practices and strategies in compliance with the Ramsar Convention obligations have been contributing to severe degradation of Beeshazar Lake, a Ramsar site in central Nepal. The surface water quality and characteristics of underlying sediments were studied to determine the limnological status of the lake. Water quality in Beeshazar Lake was found less favorable to aquatic organisms, with low pH and transparency, low dissolved oxygen (DO), and high nutrient concentrations (Nitrogen and Phosphorus), challenging the conservation of critically endangered gharial, a vulnerable marsh crocodile and many fish species. The lake was found eutrophic in nature by nitrogen concentration and transparency and hyper-eutrophic by phosphorus criteria. Lake sediments were high in organic matter content and nutrient concentrations, signifying a potential internal source of nutrient loading in the overlying water. There were no significant variations in the water and sediment quality between sampling sites except for transparency, sedimentary organic matter content (OM) and total nitrogen concentration (TN). This study provided useful information for decision makers aimed to the conservation and sustainable management of the lake.