The chemical environmental factors of several artifical reservoir in the Kang won and Chung chong buck do are investigated during spring season, 1969. The thermal stratification is formed when the wide surface of the shallow ground water has come into contact with the atomosphere, the temperature of which is higher than that of ground water in the day time. The amounts of COD, Cl^-, SiO₂, Total hardness and Alkalinity in the bottom layer water inclined to increase than in the upper layer water. Regarding the amounts of chemical constituents in those artifical reservoirs its belong to oligotropic lake with characterless.