HR: 0800h
AN: H21C-1363    [Abstracts]
TI: Some Remarks on the Boussinesq Equation and dQ/dt - Q Recession Analysis
AU: * Rupp, D E
EM: ruppd@lifetime.oregonstate.edu
AF: Dept. of Bioengineering Oregon State University, 116 Gilmore Hall, Corvallis, OR 97331 United States
AU: Selker, J S
EM: selkerj@engr.orst.edi
AF: Dept. of Bioengineering Oregon State University, 116 Gilmore Hall, Corvallis, OR 97331 United States
AB: Various analytical expressions of unconfined aquifer drainage have been derived from the Boussinesq equation. With the exception of the kinematic wave approximation, these solutions require a homogeneous aquifer. Yet many soils show a decrease in saturated hydraulic conductivity (K) with depth. Here new solutions are given to the Boussinesq equation for a horizontal aquifer in which K varies vertically as a power law. For the recession limb of the hydrograph, it is shown how the solutions appear in log(-dQ/dt) - log(Q) space, where Q is discharge. Though plotting recession data as dQ/dt versus Q can be an informative analysis technique, care must be taken to avoid misinterpretation. We discuss how use of a constant time step when approximating the slope of the recession limb can lead to artifacts in graphs of log(-dQ/dt) versus log(Q), and present improved methods for calculating dQ/dt.
DE: 1829 Groundwater hydrology
DE: 1847 Modeling
DE: 1860 Streamflow
SC: Hydrology [H]
MN: Fall Meeting 2005