Prediction of runoff hydrographs in ungauged basins - Runoff Prediction in Ungauged Basins: Synthesis across Processes, Places and Scales - page 231

Figure 10.4. Comparison of the catchment of a losing stream in an arid climate (Walnut Gulch, Arizona, top) and a slightly gaining stream in a
humid climate (Taffa, Austria, bottom). Photos: D. Goodrich, C. Reszler.

the prairies have been swampy and most of the area has
been tile drained for agricultural purposes (Herget, 1978 ;
Hay and Stall, 1974 ). The flow paths tend to be very short:
macropore flow from the surface into the tile drains, which
are connected efficiently to the drainage channels. The
runoff response is therefore very flashy. In contrast, the
Gurk catchment has event response times of a few days,
even though the catchment area is much smaller than that
of the Vermilion. This is due to large subsurface contribu-
tions to stormflow as a result of the highly permeable
rock (weathered phyllites) (see Gaál et al., 2012 , and
Section 9.2.2 ).
When water reaches the channels, channel routing takes
place. The movement of the water in the channel is con-
trolled by the stream geometry, the roughness and the
water level itself. Often there is a complex interaction
between the stream water and the aquifer (e.g., Derx
et al., 2010 ). Depending on the relative water levels of
the stream and the aquifer, the stream may lose or gain

water from the aquifer and this may vary with time. Typic-
ally, arid climates often have losing streams, while in
humid climates gaining streams prevail, but almost always
this varies very much along the reach over short distances
( Section 2.2.2 ). An example of streams in arid and humid
climates is given in Figure 10.4 .
So far, the processes involved in producing the runoff
hydrographs have been discussed from a Newtonian per-
spective, in the spirit of Freeze and Harlan s( 1969 ) blue-

print for a physically based, digitally simulated
hydrological response model. As discussed in Section
2.1.1 , catchments are complex systems resulting from the
co-evolution of climate, geology, soils, topography and
vegetation, so there may be interdependencies among the
characteristics across a wide range of time scales that go
beyond the description above. For example, the slow
response of the Gurk catchment in Figure 10.2 is a
result of the co-evolution of landform and hydrological
processes where the large subsurface contributions lead

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