洪水资源化是实施渭河流域关中段流域资源综合管理和实现区域经济可持续发展的必然要求和重要途径。通过对渭河流域关中段来水来沙丰枯变化规律和河道冲淤特性的分析,从有利于输水输沙减少泥沙淤积考虑,确定渭河中游洪峰2000m³/s、渭河下游段3000m³/s为洪水利用起算标准;依据这一标准,计算出林家村—魏家堡河段平均年可利用洪水水量、洪水沙量分别为4.038×10⁷m³、6.83×10⁶t,魏家堡—咸阳河段平均年可利用洪水水量、洪水沙量分别为为9.139×10⁷m³、6.05×10⁶t,咸阳—华县河段平均年可利用洪水水量、洪水沙量分别为1.617×10⁸m³、1.843×10⁷t;流域综合管理过程中,必须引入风险管理机制,利用优化理论寻找平衡机制,实现流域防洪、供水和生态保护兼顾的最佳效益。

Water shortage, flood prevention and disaster mitigation are important problems awaiting to be dealt with in the Weihe River of Shaanxi Province. Under this situation, floodwater utilization would become an important way to realize comprehensive management of resources and the sustainable development of regional economy.In Guanzhong area which is located at the lower reaches of the Weihe River. The Weihe River is the biggest branch of the Yellow River, passing through Gansu, Ningxia and Shaanxi provinces. The middle reaches of the Weihe River is located in Shaanxi Province, with broad water ways, many shoals and scattered water flow. The lower reaches of the Weihe River is located in Xianyang, with serious channel siltation and small gradient. The flood resulted from heavy rain is the major disaster in these two areas. In general, the floodwater takes up about 33.1%-39.3% of the total runoff annually; the silt is about 60.1%-74.3%, where all data are mean values. It can be seen that a great deal of water and silt comes from the floodwater. By analyzing features of water, the quantity of silt coming from the upper reaches of the Weihe River, and the channel siltation, we establish the criteria as the initial values to evaluate the floodwater utilization; that is, the flood peak with a velocity of 2000m³/s in the middle reaches of the Weihe River, and that of 3000m³/s in the lower reaches of the Weihe River. According to these criteria, based on calculations we obtain the annual average quantlity of the available floodwater and silt from Linjiacun to Wijiabao is 4.038×10⁷m³, and 6.83×10⁶ t respectively, the quantlity of the available floodwater and silt from Weijiabao to Xianyang is 9.139×10⁷m³, and 6.05×10⁶ t respectively, and the quantlity of the available floodwater and silt from Xianyang to Huaxian is 1.617×10⁸m³, and 1.843×10⁷t, respectively. It is necessary to establish the risk management system to gain the optimal effects of flood prevention, water supply and ecological protection.