Characteristics of Surface Flow on the Forest Fire Sites by Using Rainfall Simulator

摘要

For the purpose of this study, the characteristics of surface flow through the survey of rainfall intensity and degree of slope on fire sites by using rainfall simulator was examined and analysed. And also the relationship between the amount of surface flow and rainfall intensity, degree of slope and elapsed year after forest fire occurrence influencing on the surface flow were analysed. The results obtained were as follows: 1. The amount of surface flow by year of occurrence of forest fire was increased 2.2 to 3.2 times as rainfall intensity was increased by 30 mm/hr, and 1.5 to 1.9 times as degree of slope was increased by 10°. 2. Even though ground vegetation in forest fire sites was recovered more than 80%, the amount of surface flow in initialrainfall was relatively much and it seemed that vegetation didn't play substantial roles in reducing runoff. 3. The amount of surface flow by rainfall intensity and degree of slope in accordance with elapsed years after forest fire was reduced 22.3% to41.8% in three years after fire as compared to the first year of fire occurrence. The amount of surface flow were significantly differentiated by rainfall intensity and degree of slope in the first year of fire occurrence and the difference were gradually reduced afterwards. 4. In the analysis on influences of each factors on the amount of surface flow on forest fire sites, the amount of surface flow was significant differences in major impacts of each rainfall intensity, degree of slope and elapsed year after fire and interaction of rainfall intensity X degree of slope and rainfall intensity X elapsed year after fire, but no differences were observed in interaction of degree of slope X elapsed year after fire and rainfall intensity X degree of slope Xelapsed year after fire. Rainfall intensity was the most affecting factor on the amount of surface flow and followed by degree of slope and elapsed year after fire.