Geoscience Reference
In-Depth Information
and Loague, 2001). QPBRRM has many similarities to KINEROS but uses a 1-D analytical infiltration
component based on the Philip equation (see Box 5.2); a 1-D kinematic wave overland flow component
applied on a constant width hillslope plane discretisation of the catchment; and a 1-D kinematic wave
channel network routing algorithm. The model takes account of spatially variable runoff generation by
an infiltration excess mechanism and the downslope infiltration of runoff as runon onto areas that are not
yet saturated. The requirements of the model are therefore the spatially variable infiltration parameters
for every point in the catchment and the effective parameters of the storage-discharge relationship for the
overland and channel flow model components. InHM is a finite element solution of the coupled surface-
subsurface equations in three dimensions and can incorporate heterogeneity of soil characteristics at the
element scale.
The story starts with Keith Loague's PhD research, when he applied the QPBRRM model to the R-5
catchment (as well as several other catchments of different types) using data on soil charactersitics for
the three main soil types as reported by Sharma
et al.
(1980) (see Loague and Freeze, 1985). Loague and
Gander (1990) then added a further 247 infiltration measurements (see Figure 5.14), based on a grid of
25 m spacing (157 sites) and two transects with measurements at spacings of 2 m and 5 m. Loague and
Kyriakidis (1997) used a geostatistical kriging analysis to interpolate these data to any 1 m
2
grid point in
the catchment, taking account of the effects of temperature on the density and viscosity of the infiltrating
water that had been ignored in a similar interpolation by Loague and Gander (1990) and the modelling
Figure 5.14
Patterns of infiltration capacity on the R-5 catchment at Chickasha, OK: (a) distribution of
247 point measurements of infiltration rates; (b) distribution of derived values of intrinsic permeability with
correction to standard temperature; (c) pattern of saturated hydraulic conductivity derived using a kriging
interpolator; (d) pattern of permeability derived using kriging interpolator (after Loague and Kyriakidis, 1997,
with kind permission of the American Geophysical Union).
