从地学的角度出发,选择最适宜的行河边界条件和最小的社会、经济损失为原则,通过对地质、地貌、水文等学科的深入分析,在GIS和数学模型等技术的支撑下,研究了黄河下游洪灾风险的消减问题,探讨在现今黄淮海平原是否存在一条可行的最优后备流路．研究认为,在水沙矛盾不能根除的现实条件下,最优后备流路的识别可选择边界条件较优和社会、经济损失较小的重叠区域．通过对黄河下游地区的地形、构造运动、地壳稳定性,以及社会、经济发展状况的详细分析,运用距离加权函数和最低成本路径函数计算得到最优后备流路．后备流路完全摆脱鲁西中隆起的影响,全线在海黄裂谷中行河,有利于河道的相对稳定;后备流路的比降增加36．2％、长度缩短15．4％、曲率减小12．2％,有利于行水行沙．总之,启用后备流路能较好地缓解现行黄河的洪灾风险．虽然存在部分人口和城镇搬迁,基础设施的重建以及现有流路被废弃地区用水短缺及导致的生态、环境退化等问题,但与国家治黄的巨大累积投入相比较,其绝对数量仍然是可接受的．在被确定的后备流路区域内,由于水资源的充裕和相应需要进行的基础设施建设,将带动地区社会经济发展,获得难得的发展机遇． From the perspective of geosciences, we select the most appropriate boundary conditions and the minimum social and economic losses as the principle. Through the in-depth analysis of the geology, geomorphology and hydrology, we have studied on the support of technologies such as GIS and mathematical models The problem of flood risk reduction in the lower reaches of the Yellow River and whether there is a viable optimal backup flow path in Huang-Huai-Hai Plain today. According to the research, under the realistic condition that the contradiction between water and sediment can not be eradicated, the optimal back-up flow path can be identified by choosing the overlapping area with better boundary conditions and less social and economic losses. Through the detailed analysis of topography, tectonic movement, crustal stability and social and economic development in the lower reaches of the Yellow River, the optimal back-up flow path is calculated by using the distance weighting function and the least-cost path function. The backup flow path is completely out of the influence of the Luxi medium-sized uplift, and all the rivers in the Yellow Sea Rift are conducive to the relative stability of the watercourse. The specific gravity of the backup flow path is increased by 36.2%, the length is shortened by 15.4% and the curvature is decreased 12.2%, is conducive to water line sand. In short, the opening of the backup flow path can better alleviate the current flood risk of the Yellow River. Although there are some population and urban relocation, reconstruction of infrastructure and water shortage in the abandoned areas of the existing roads and the resulting ecological and environmental degradation, the absolute amount compared with the huge accumulated investment by the state in treating yellowing is still acceptable Accepted. In the confirmed reserve flow route area, due to abundant water resources and the corresponding infrastructure construction required, it will drive the socio-economic development in the region and provide rare opportunities for development.