祖厉河流域最大暴雨洪水特性研究

Study on the Characteristics of Maximum Rainstorm and Flood in the Zuli River Basin

依据祖厉河流域实测水文资料,利用水文学、数理统计学等理论和方法,分析了流域暴雨、洪水的时空分布规律,拟合了最大暴雨量P随暴雨历时T变化的平均关系曲线及外包线,选取上下游水文站4场相应典型洪水过程,分析其变化特性和暴雨成因。结果表明:流域10 min、30 min、1 h、3 h、6 h、24 h最大暴雨量多年平均值分别为7.9、13.3、16.6、23.3、27.6、38.2 mm,暴雨量最大值主要发生在关川河流域,最小值均发生在最下游的靖远站;最大暴雨和洪水年内分布主要集中在汛期,历年最大暴雨量除会宁站30 min略有增加外,其余站点各时段最大暴雨量均呈减小趋势,年最大流量总体呈持续减小趋势,发生大洪水的频次在减少;会宁、郭城驿、靖远站历年最大流量均值分别为248、415、474 m3/s,100 a一遇洪峰流量分别为1263、1525、2395 m3/s,50 a一遇洪峰流量分别为1026、1297、1969 m3/s;流域洪水过程与暴雨量及其时空分布有关,较大洪水一般是全流域普遍发生大暴雨所致,中下游水文站控制断面洪水过程经常发生连续涨落的复式洪峰;干流洪水传播时间与洪峰流量大小和河道比降有关,会宁—郭城驿段洪峰传播时间为5.0~13.0 h,郭城驿—靖远段洪峰传播时间为4.6~11.1 h。

Based on the measured hydrological data of the Zuli River basin,by using theories and methods such as hydrology,mathematical statistics,the spatial and temporal distribution law of rainstorm and flood in the basin was analyzed,and the average relationship curve and outsourcing line of the maximum amount of rainstorm P with the T that changed following rainstorm time were fitted.The 4 corresponding typi cal flood processes of the upstream and downstream hydrological stations were selected to analyze its changing characteristics and the causes of rainstorms.The results show that the multi year averages of the maximum rainfall of 10 min,30 min,1 h,3 h,6 h and 24 h in the basin are 7.9,13.3,16.6,23.3,27.6 and 38.2 mm respectively and the maximum amount of rainstorms occur mainly in the Guanchuan River basin but the minimum value are all aroused in the lowest reaches of Jingyuan Station;The distribution of the maximum rainstorms and floods dur ing the year are mainly concentrated in the flood season,the maximum amount of heavy rain,annual maximum flow rate and the frequency of major floods in the sites at all times are all show decreased trends except Huining Station with slight increase in 30 min.The average of the maximum discharge of Huining,Guocheng and Jingyuan stations is 248,415 and 474 m3/s respectively.Besides,the 100 year frequency flood peak discharge is 1263,1525 and 2395 m3/s respectively and 50 year frequency flood peak discharge is 1026,1297 and 1969 m3/s respectively for the three different stations.The flood process of the basin is related to the amount of rainstorm and its spatial and temporal distribution,and the larger flood is generally due to the heavy rain occurred in the whole basin,the middle and lower reaches of the hydrolog ic station control section flood process often occurs continuous rise and fall of double flood peak,the main flow flood transmission time is re lated to the flood peak discharge size and channel slope,the travel time at the section between Huining and Guocheng is 5.0-13.0 h and the travel time of peak flow in Guocheng-Jingyuan section is between 4.6-11.1 h.