Vegetation Characteristics and their Effect on Runoff and Peak Rates from Small Watersheds

Two small brush wood watersheds W₁F (1.45 ha) and W₂F (.87 ha) were calibrated between 1961-68 and W₁F was clearfelled and planted up with two species of Eucalyptus in 1969. Analyis of precalibration data 1961-68 indicated that W₂F gave 18% less runoff & 63% lower peak rates as compared to W₁F. Data analysis for the post treatment period 1969-74 indicated that W₁F now gives 28% less runoff and 73% lower peak rates as compared to W₂F. In order to find out the causes for this reduction, the vegetation in the two watersheds was surveyed and it was found out that W₁F has 21 % more ground cover, 24% more trees, 39% more leaf litter, 68% more above ground and 11 % more under ground phytomass.