The study was conducted between January and December, 2018. The objective of the study was to assess the current status of physicochemical water quality parameters of Lake Hayq. An integrated water sampling method was used. Water quality parameters such as Dissolved Oxygen, pH, Temperature, conductivity, turbidity and Secchi-disk depth were measured in situ using digital water quality parameters and Secchi disk. Other nutrients, Nitrate, Ammonia, Total Phosphorous, Soluble Reactive Phosphorus, Silicon dioxide, Chlorophyll-a, and total alkalinity were
analyzed in Addis Ababa University Limnological laboratory. Ammonium ion was analyzed in the Addis Ababa University Isotope laboratory. The collected data were analyzed using Two Way ANOVA through the application of SPSS Version 16 Software. In Lake Hayq, the mean physicochemical water quality parameters, temperature (23°C), pH (8.8), Secchi disk depth (3.5m), turbidity (4.5 NTU), total alkalinity (8.8 meqL-1),Total Phosphorous (39 μgL-1), Soluble Reactive Phosphorus (8.3 μgL-1), Nitrate (160.90 μgL-1), Ammonium ion (210 μgL-1), Silicon dioxide (142.3 μgL-1), Chlorophyll-a (4.03 μgL-1), and conductivity (920 μS cm-1) were recorded. Based on Carlson’s index of
trophic state (TSIC), Lake Hayq is mesotrophic (TSIC= 40.03). Lake Hayq has more inorganic nutrient value due to nutrient enrichment through runoff, siltation and point source of pollution from nearby Lodges which will accelerate the eutrophication process in the lake shortly. Therefore, integrated waste management and watershed management should be implemented to minimize the nutrient load and restore Lake Hayq.