METHOD AND SYSTEM FOR RETURNING DAM DEPOSIT DOWNSTREAM

To provide a method and a system for returning a dam deposit downstream, which does not adversely affect downstream rivers even if silt clay contained in the dam reservoir deposit is supplied downstream of the dam.SOLUTION: This method for returning a dam deposit downstream is a method for returning a dam deposit downstream that supplies deposit of a dam reservoir to the downstream of a dam, and comprises a step of classifying the deposit dredged from a reservoir 2 in a normal state into a silt clay component having a predetermined particle size or less and sand having a predetermined particle size, a step of sending the classified silt clay to a sludge reservoir 12, a step of storing and precipitating silt clay in the sludge reservoir, a step of supplying water from the reservoir to the sludge reservoir during floods, a step of stirring the precipitated silt clay to make mud water, and a step of supplying mud water downstream of the dam based on the discharge rate (m/sec) of the dam.SELECTED DRAWING: Figure 1 【課題】ダムの貯水池の堆積物に含まれるシルト粘土分をダムの下流に供給しても下流の河川へ悪影響を及ぼさないダム堆積物下流還元方法およびシステムを提供する。【解決手段】このダム堆積物下流還元方法は、ダムの貯水池の堆積物をダムの下流に供給するダム堆積物下流還元方法であって、平常時に貯水池２から浚渫された堆積物を所定粒径以下のシルト粘土分と所定粒径を超えた砂とに分級し、分級されたシルト粘土分を排泥貯留部１２に送り、排泥貯留部でシルト粘土分を貯留し沈殿させ、洪水時に貯水池から排泥貯留部に給水し、沈殿したシルト粘土分を攪拌して泥水とし、ダムの放流量（ｍ3／秒）に基づいて泥水をダムの下流に供給する。【選択図】図１