Effects of wildfire on overland flow and erosion in the Macalister River watershed.  D.F. Williams, L.J. Bren and F.G. Craig.  January 1973.  16 pp. (unpubl.)

SUMMARY

The effects of wildfire upon overland flow and erosion were studied using plots established in two comment ecotypes of the Macalister River Watershed. The Tamboritha site was steep, rocky, and had an impermeable shallow soil. Eucalyptus macrorrhyncha, E. melliodora and E. polyanthemos were the dominant eucalypts. The Bull Plain site was also steep, but the soil was a brown loam which was deeper and more permeable than at Tamboritha. The dominant eucalypts were E. rubida and E. radiata.

Wildfire was found to increase overland flow both at Tamboritha and at Bull Plain, but the absolute magnitude of the increase was far less at Bull Plain. Erosion at Tamboritha did not appear to be affected by the fire, but was markedly increased at Bull Plain although the absolute level of increase was not high.

Ground vegetation and the litter layers at the study sites recovered in about four years. Hence any ameliorative treatments contemplated would have to last for approximately this period.

Rainfall intensity, throughfall quantity, and slope appeared to be more important variables controlling the amount of overland flow in the Macalister Catchment.