Geoscience Reference
In-Depth Information
Figure 5.13
Results of modelling the 4.4 ha Lucky Hills LH-104 catchment using KINEROS with differ-
ent numbers of raingauges to determine catchment inputs (after Faur es et al., 1995, with kind permission
of Elsevier).
More recently, Goodrich
et al.
(1997) have used data from all 29 nested subcatchments within Walnut
Gulch, with drainage areas ranging from 0.2 to 13 100 ha, to investigate the effects of storm area and
catchment scale on runoff coefficients. They conclude that, unlike in humid areas, there is a tendency
for runoff responses to become more nonlinear with increasing catchment scale in this type of semiarid
catchment as a result of the loss of water into the bed of ephemeral channels and the decreasing relative size
of rainstorm coverage with catchment area for any individual event. Detailed modelling studies were made
using KINEROS for three of the catchments, LH-106 (0.34 ha), LH-104 (4.4 ha), and WG-11 (6.31 km
2
).
The model was calibrated by adjusting three multipliers applied to the distributed patterns of overland flow
roughness, mean soil hydraulic conductivity and the coefficient of variation of hydraulic conductivity,
which is allowed to be heterogeneous with a log normal distribution (Woolhiser and Goodrich, 1988;
Smith and Goodrich, 2000), to improve the predictions for 10 calibration events. Twenty additional
events were used to evaluate the calibrated models. The model was relatively successful in predicting the
responses for the two small catchments, less so for WG-11 where the performance on the validation events
was much worse than in calibration. The results, however, confirmed the tendency towards increasing
nonlinearity at the larger scale.
KINEROS has continued to be applied at Walnut Gulch, including the modelling of sediment yield
(Lopes and Canfield, 2004). One study of interest is that of Canfield and Goodrich (2006) who looked
at the effect of both parameter and geometric simplifications of KINEROS in predicting both runoff
and sediment yield for the LH-104 catchment. Their conclusion was that parameter simplification, by
