A Regional Analysis of the Controls on the Variability of Event-based Runoff Coefficient in Indiana
Abstract
Event-based runoff coefficient, the ratio between direct runoff and precipitation volume, is an indication of hydrological response of a watershed to the rainfall input. The spatial and temporal variability in runoff coefficient is caused by several climate and watershed related characteristics such as annual rainfall, land use, rainfall intensity, and antecedent soil moisture. This study analyzes the role of different controls on the variability of event runoff coefficient. A total number of 2000 rainfall-runoff events from six watersheds in Indiana from 1991 to 2020 were used to analyze the factors affecting the runoff coefficient. Graphical analysis using violin plots shows that antecedent soil moisture is positively related to runoff coefficient; whereas rainfall intensity is inversely related to runoff coefficient. However, there is no significant relationship between rainfall amount and direct runoff. Moreover, the results of seasonal analysis using the correlation method reveal that the influence of initial soil moisture conditions on runoff coefficient is even stronger during dry seasons. The spatial variability is analyzed in terms of factorial-ANOVA. It indicates that land use plays an important role in rainfall-runoff process, especially the percentage of impermeable land cover but soil groups do not seem to exert a major control on runoff generation.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.H15K0919X