STUDY ON RIVER FACILITIES HARMONIOUS WITH ENVIRONMENT

无水毁河流的开发，对河流自然环境造成了严重破坏。为恢复河流环境，应建设防洪与环保双重功能的设施。本文讨论了丁坝的作用。丁坝的护岸作用是有效的，丁坝周围形成的局部冲刷有利于鱼类的栖息。本文共分三个部分。第一部分建立了二维河床演变的数值计算方法，并通过对弯曲河道的河床演变进行模拟，验证了方法的有效性。然后，将该方法应用于现场数据。预测了该水库的位置和枯水期曲流河的形成。第二部分对丁坝的护岸作用和丁坝局部冲刷（池）形态进行了评价。在不考虑非平衡输沙的情况下，局部冲刷剖面的模拟是不可能的。最后，通过对仙台江的观测，探讨了适合鱼类栖息的池塘条件。较深的底质组成的深池，粒度分布广泛，是鱼类的栖息地。

The development of rivers free from flood damage has resulted in serious ruin of natural river environment. In order to rehabilitate the river environment, we should construct the facilities with both functions on the flood control and the environmental protection. In this paper we have discussed the functions of spur dikes. The spur dike is effective in the protection of bank and the local scour formed around the spur dike will be suitable to the habitat of fishes. This paper is composed of three parts. In first part, the numerical method for 2-dimensional bed evolution is developed and the validity is verified by the simulation of bed evolution in the meandering channel. Then, the method was applied to the field data. The place of the pool and the formation of the meandering streams at the low water were predicted. In second part, using the method the function on the protection of the bank and the profile of the local scour ( pool ) around the spur dike are evaluated. The profile of local scour is not simulated without considering the non-equilibrium sediment transport. In last part the conditions on the pool suitable to the habitat of fishes are discussed from the observation in the Sendai river. The deeper pool composed of the bed material with wide-ranging grain sizes is available for the habitat of fishes.