To evaluate the bottom sediment and water quality change of dam reservoirs, laboratory column experiments using dredged bottom sediment and water of the dam reservoir were conducted for 18 months. The environmental, microbiological and mineralogical changes of the sediment and water in the columns were investigated. Nitrate-reducing and iron-reducing reactions occurred in the 10-12cm depth of the column, and the environment became anaerobic. Denitrification and methane generation due to microorganisms similar to paddy field were observed in the layer, however, the activity of sulfate-reducing bacteria was low. It showed the absence of the sulfate and supply of energy sources in the sediments. No mineralogical change in the sediments was observed under the anaerobic condition.
