抄録
In the Barato River, eutrophication has been occurring because of urban effluent and river cutoff improvements. To improve the water quality, additional water has been conveyed into the Barato River since 2007. This study aims to evaluate the effects of such conveyance on water quality. At the Jyobukobon, BOD was found to increase by conveyance from the Sosei River and to decrease by conveyance from the Ishikari River. At the Tarukawa-Goryumae, BOD was found to decrease slightly by water conveyance from the Sosei River but to show no clear changes in the year after conveyance from the Ishikari River. To evaluate the effects of water conveyance,an ecosystem model was developed that enables year-round predictions, including for the freezing season. A water quality simulation for four consecutive years estimated a decrease in BOD by about 1.0 mg/L at the Jyobukobon and about 0.6 mg/L at the Tarukawa-Goryumae. Also, nitrogen density was estimated to decrease by water conveyance.
