经验方法研究下垫面变化对洪水的影响

1980s以来,人类活动对下垫面的影响加剧,研究下垫面变化对流域产汇流规律的影响具有重要意义.通过对海河流域中紫荆关、阜平两个流域分别用经验方法进行洪水模拟演算,并把洪水资料按照年代不同分时段,建立P+Pa～Rs相关关系图,分析流域下垫面变化对降雨径流相关关系的影响.建立产流量R与洪峰Qm之间的相关关系,通过统计比较不同年代的趋势线发现,在产流量相同情况下,1980s后的洪峰流量较1980s前有所减少,说明海河流域的调蓄作用有增强的趋势.同时建立流域下垫面条件改变后产流量与洪峰变化幅度的相关关系,发现流域产流量变化与洪峰变化呈正相关关系.

Impacts of altered basin landscape on floods using an empirical method

Since 1980s,with the increasing impacts of human activities on the river basin landscape,it is significant to investigate the impact of landscape changes on the rainfall-runoff regime.This paper simulated the floods occurred in the Zijingguan and Fuping catchments of the Haihe Basin using an empirical method.The flood data were segmented by time for creating the P+Pa-Rs curve to analyse the influence of the altered catchment landscapes on surface flow regime.Based on the unit hydrograph method,the relationship between the runoff R and peak discharge Qm was established.The results show that by comparison of the trendlines in different time periods,with the same runoff volume,the peak discharge after 1980s is less than that before 1980s.It indicates that the water regulation function of Haihe Basin was enhanced.Based on the relationship between the changes of runoff and peak discharge induced by the altered basin landscapes,it is found that there is a positive correlation between them.