Construction of the sediment transport model covering whole catchment area

Mano对Abukuma河进行了处理，并构建了覆盖整个集水区的500米网格尺寸的通道网络。他们开发了一个系统，通过运动波近似和输入基于AMeDas观测的分布式降雨来计算网络上的径流。然后，他们利用径流分析得到的流场，并考虑侵蚀、沉降和对流的物理过程，在同一网络上建立了一个泥沙输运模型。Izumi对1998年Abukuma河洪水携带的冲刷负荷进行了实地调查，结果表明，溢出的洪水使洪水通道的中央边缘附近出现了明显的沉积，就像天然河岸一样，而且粒度分布向另一边变细。他发展了悬移质输运理论，并证明了观测到的沉积物和粒度分布可以用该理论来解释。长林研究了阿布熊川中氮、磷和浊度物质的输运。其浓度的特点进行了调查，洪水和通常的电流。洪水期间，浊度与总氮、总磷浓度有很高的相关性。溶解组分与总氮和总磷的比率显示出根据这些总量的浓度而显著变化。这表明，比值是有效的，以确定这些负载。

Mano dealt with the Abukuma River and constructed channel network with 500m-grid size covering the whole catchment area. They have developed the system to compute the runoff on the network with the kinematic wave approximation and by inputting the distributed rainfall based on the AMeDas observation. They then have developed a sediment transport model on the same network by using the flow field obtained by the runoff analysis and by considering the physical processes of erosion, settling and convection. The model is shown to have high accuracy through the comparison with the observation.Izumi executed field survey on the wash load carried by the flood of the Abukuma River in 1998 and has shown that spilled flood into the flood channel made significant deposition near the central edge like a natural bank and the grain size distribution became finer toward the other edge. He has developed the theory on the suspended load transport and shown that the observed distributions of sedimentations and grain size are explained by the theory.Nagabayashi studied the transport of nitrogen, phosphorus and turbidity material in the Abukuma River. The characteristics of their concentration are investigated for floods and usual currents. During floods, turbidity has high correlation with the concentration of total nitrogen and total phosphorus. The ratios of the dissolved components to the total nitrogen and total phosphorus are shown to significantly change depending on the concentration of these total quantities. It suggests the ratios are effective to determine these loads.