HR: 0800h
AN: H11F-0375 [Abstracts]
TI: Similarity Analysis of Subsurface Flow Response of Hillslopes With Complex Geometry
AU: * Berne, A
EM: Alexis.Berne@wur.nl
AF: Wageningen University, Nieuwe Kanaal 11, Wageningen, 6709 PA
AU: Uijlenhoet, R
EM: Remko.Uijlenhoet
AF: Wageningen University, Nieuwe Kanaal 11, Wageningen, 6709 PA
AU: Troch, P A
EM: Peter.Troch@wur.nl
AF: Wageningen University, Nieuwe Kanaal 11, Wageningen, 6709 PA
AB:
Recently, Troch et al (2003) introduced the hillslope-storage Boussinesq (hsB) equation to describe subsurface flow and
saturation along complex hillslopes. The hsB equation can be linearized and further reduced to a diffusion-advection equation
for hillslopes with constant bedrock slopes and exponential width functions. This paper presents a dimensional analysis of
the latter equation in order to study the pure drainage flow response, which, once normalized by the flow volume, is defined
as the characteristic response time distribution (CRTD). In the Laplace domain, an analytical expression for the discharge is
obtained and used as moment generating function to derive the analytical expressions for the CRTD moments. These moments, in
a dimensionless form, can be expressed as function of a subsurface flow similarity parameter, hereafter called the hillslope
P\'eclet number, and a group of dimensionless numbers accounting for the initial condition effects. The analysis of their
respective influences on the first four CRTD central moments shows that the first studied type of initial condition (uniform
water table depth) has a strong impact on the dimensionless mean response time of the CRTD but negligible effect on the
higher order moments, while the second studied type of initial condition (steady state water table profile) has a limited
effect on all first four CRTD moments and hence, in this case, the hillslope P\'eclet number completely defines the
subsurface flow similarity between hillslopes.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1869 Stochastic processes
DE: 1625 Geomorphology and weathering (1824, 1886)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting