Abstract:
Peraru, Nochchimoddai and Mamaduwa are the three village tanks lying in a cascade line
in Vavuniya district. The water resource of Peraru village reservoir was treated by National Water
Supply and Drainage Board of Vavuniya, distributed to the local public. The objective of the study
was to analyze the physical and chemical characteristics of water in the village reservoirs of Peraru,
Nochchimoddai and Mamaduwa. Water samples were collected at the selected three locations of
each reservoir weekly from March to April 2021 to determine the physico-chemical parameters such
as Dissolved Oxygen (DO), pH, Electrical Conductivity (EC), turbidity, temperature, nitrate and
phosphate. The results of physico-chemical parameters of selected tanks were statistically tested using
ANOVA and compared among the three village tanks and with the standard water quality guidelines
for inland surface water. When comparing the physico-chemical parameters of water among the
selected tanks, DO and EC were significantly high in the Peraru village tank. Nitrate was significantly
high in Nochchimoddai village tank whereas phosphate was significantly high in Mamaduwa village
tank. Although not showed significant differences, the turbidity of the Nochchimoddai village tank
was slightly higher than that of the other two tanks. Higher turbidity and nitrate levels and lower
DO levels than standard values in Nochchimoddai tank were caused by the presence of floating
aquatic weeds. According to the standards, phosphate levels of the selected three tanks recorded
higher values. Contamination of fertilizers and detergents might be the reason for the increased
level of phosphate and continuous contamination of phosphate could lead to eutrophication in the
future. A high concentration of dissolved salts in the Peraru tank leads to an increase in the EC.
Water temperature and pH did not show significant differences among Peraru, Nochchimoddai and
Mamaduwa village tanks. Meanwhile, pH of water in the three tanks was found to be neutral.
