Prediction of runoff hydrographs in ungauged basins - Runoff Prediction in Ungauged Basins: Synthesis across Processes, Places and Scales - page 250

Figure 10.22. Hydraulic geometry from field surveys in the Trisanna catchment, Tirol, Austria; area 98 km². From Kohl ( 2011 ).

same sites, the first time in spring and the second time in
late summer or autumn. For most of the sites the summer
and autumn runoff coefficients were found to be much
larger than the spring ones, in some instances by a factor
of 10. The sites were located on pastures where grazing by
cattle during summer leads to soil compaction and
increased runoff. During winter, earthworms and other

animal activities increase the soil permeability, thereby
lowering the spring runoff coefficient, before another cycle
of compaction follows. A detailed process model would
have to model the cattle activity (with data on the number
of head per unit area) and earthworm activity. Clearly, one
cannot hope to reduce all uncertainty by including more
detail into the models.