The restoration of damaged mire is important as it comprises of unique habitat which rarely found anywhere else. Among many techniques, damming has gained widespread use in mire restoration. However, its effect on the restoration of water quality has yet to be examined, because the objectives of damming have been mainly hydrological. This study attempts to clarify how dams affect the water quality in a bog-mire wetland by comparison with previously gathered data from a point of natural conditions and two points of disturbed conditions. The effect of the dams in re-establishing the natural vegetation was also studied.