Hydrologic effects of a stretch of forest road.  L. J. Bren and C. J. Leitch.  May 1985.  17 pp. (unpubl.)

SUMMARY

Runoff from a stretch of forest road was measured continuously both before and after passage across a section of undisturbed forest.

The volume of storm runoff (‘stormflow’) per unit road area was found to be best predicted by the depth of rainfall, whereas the peakflow per unit road area was best predicted by the maximum 60-minute rainfall intensity. The results were compared with models of stormflow and peakflow generation derived from flow data from a small forested catchment near the road stretch. This showed that the presence of a length of road in this catchment would lead to more stormflow for small and moderate storms but would make little difference for larger storms. However, the road would possibly make a substantial contribution to the peakflow for all storm sizes, although there could be timing differences in reaching peaks. The passage of runoff across a short length of natural forest slope appeared to make little difference to the flow.

Thus, if the outflow of road culverts is to infiltrate slopes, then special measures may be necessary to adequately distribute the water over the slope and to maintain infiltration pathways.

Also published:

Bren, L.J. and Leitch, C.J. (1985)  Hydrologic effects of a stretch of forest road.  Aust. For. Res. 15(2): 183-94.