淮北平原农田暴雨径流过程的尺度效应

Scale effects of storm-runoff processes in agricultural areas in Huaibei Plain

基于1997-2007年汛期11场暴雨径流观测数据,对比淮北平原不同集水面积(1 600 m2、6 hm2、和1.36 km2)尺度下的农田暴雨产流过程差异,并分析其主要影响因素,探索农田暴雨径流过程尺度效应。结果表明,相同次暴雨下小尺度单位面积上的洪峰流量明显高于大尺度和中尺度,而径流深小于后两者,引起该差异的主要因素可能在于小尺度下缺乏地下水出流条件且植被截留能力相对较强。中尺度和大尺度间的暴雨径流过程相似,但中尺度下的径流深和单位面积洪峰流量都大于大尺度,大尺度径流场对径流的滞蓄能力相对较强可能是其主要原因。

Based on the observed rainfall and runoff data in 11 rainstorm events during the flood season from 1997 to 2007 at three different spatial scales（plot： 1600m2,field： 6 hm2 and small catchment： 1.36km2） in Huaibei Plain,China,the scale effects of storm-runoff processes in agricultural areas of Huaibei Plain were analyzed.The differences in storm-runoff processes and their main influences at different scales in agricultural area were evaluated.Results showed the storm-runoff process at the small plot was obviously different from that in the other two catchments,and the runoff depth is smaller and flood peak modulus is larger in the small plot than in the field and two catchments during same rainstorm event.At the plot scale,there is no lateral groundwater discharge process,which may be the main reason for the different storm-runoff processes.The runoff processes in the 6 hm2 field and 1.36 km2 catchments were similar,but the runoff depth and flood peak modulus at the catchment 1.36 km2 is smaller than that at the middle scale.This research indicated that storage capacity in the large scale may be the main reason for the smaller runoff depth and flood peak modulus.