2017年汉江秋季洪水特性及预报调度分析

2013年丹江口大坝加高工程完成后，遭遇连续枯水，各年度蓄水严重不足，2017年发生明显秋汛，防汛部门科学调度，取得了统筹防洪、大坝蓄水安全与监测试验等多目标共赢的成果。通过分析汉江2017年秋汛的水雨情发展、洪水地区组成、水情预报及水库调度等，解析了汉江此次秋汛过程的降雨、洪水特性，水情预报精度水平及水库调度的成效。分析表明：汉江9月上中旬降雨起筑底作用，9月23日开始的连续强降雨过程累计雨量大、覆盖面积广，直接导致汉江连续涨水过程；丹江口入库洪水最大15 d洪量接近秋季10 a一遇，丹皇区间最大7 d洪量超过秋季20 a一遇；丹江口水库实施拦洪削峰调度，削峰率均在50%以上，削减中游干流主要站洪峰水位约2 m，避免了中下游分洪民垸和杜家台分洪。

Autumnal flood analysis and forecast operation of Hanjiang River in 2017

After the completion of Danjiangkou reservoir dam heightening project in 2013, the reservoir suffered a continuous low water, and the annual water storage was seriously deficient. In the autumn 2017, there occurred an obvious seasonal flood, with the scientific operation, the flood control department achieved a multi-objective win-win results in the aspects of flood control, and dam safety monitoring test. Through the analysis of the rain and flood process development, flood region composition, hydrological forecasting of 2017 autumnal flood, this paper summarizes the rainfall process, flood characteristics, flood forecast accuracy and the achievements of reservoir operation. The results show that the rainfall in the Hanjiang River Basin in mid-September formed the foundation of the flood, since 23rd Sept., the subsequent heavy rainfall with a large accumulated rainfall and coverage directly caused the flooding process of the Hanjiang River; the max. 15d flood volume into Danjiangkou Reservoir closed to 10 years frequency of autumnal flood, the max. 7d flood volume of the Dan-Huang interval area was over 20 years frequency of autumnal flood. The reservoir implemented an operation way of flood detention and peak reduction, by which, the peak-reduced rate was more than 50% with the flood peak water level reduced in about 2 m at the lower reaches' stations of the reservoir, and the operation of flood diversion polders and Dujiatai flood detention zone in the mid-low reach were avoided.