Study on Spatial Variability of Rainfall–Runoff and Rainstorm–Flood Relationships in Mountainous Area of the Daqing River Basin

Abstract

Spatial variability of rainfall–runoff and rainstorm–flood relationships are very important to water planning and utilization. Taking the mountainous area of Daqing River basin as the studied area, this paper reveals the variability point and inconsistency characteristics of rainfall–runoff and rainstorm–flood and presents a new approach using a copula function and geostatistical method to show spatial variability of rainfall–runoff and rainstorm–flood with the proposed virtual runoff and virtual flood. The results demonstrate that rainfall–runoff and rainstorm–flood relationships exist during great changes before and after variation point. Especially after the variation point, rainfall–runoff and rainstorm–flood relationships show more inconsistency with moderate and strong spatial variability, which are mostly in the northern area of the basin. Meanwhile, spatial variability in the rainfall–runoff relationship is similar to that in the rainstorm–flood relationship.