ブランタス川中流域の河床変動

Abstract

インドネシア東部のブランタス川中流域の土砂および洪水災害対策を考えるに当って, まず河床変動特性を明らかにすることが重要である。ブランタス川の河床変動にはクルー山の噴火に伴う土砂流出と上流に築造されたダム堆砂が大きな影響を与えている。ここでは, 過去の河床形状の調査結果に基づき1990年の噴火前後の河道の土砂収支を調べ, 河床変動に及ぼす噴火やダムの影響を調べるとともに, 一次元数値計算によって河床変動のシミュレーションを行った。

The topographical changes of Brantas River are principally dependent upon four factors. First factor is the huge volcanic eruption of Mt.Kelud. The tremendous production of sediment results in the sever bed aggradation. Second factor is the development of sediment erosion control works in the tributaries. In fact, a lot of sabo facilities have mitigated the sediment inflow to Brantas River. Third factor is the construction of damas and weirs. Several multipurpose dams and weirs have already completed. They must cause the bed degradation downstream of them. The last factor is the sediment excavation. In this paper we have investigated the effects of these factors on the bed variation of Brantas middle reach from Mojokerto to Kediri and simulated the bed variation using an one-dimensional model.