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Evaluation of a distributed catchment scale water balance model
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Mancini, Marco Paniconi, Claudio Wood, Eric F. Troch, Peter A. |
| Copyright Year | 1993 |
| Description | The validity of some of the simplifying assumptions in a conceptual water balance model is investigated by comparing simulation results from the conceptual model with simulation results from a three-dimensional physically based numerical model and with field observations. We examine, in particular, assumptions and simplifications related to water table dynamics, vertical soil moisture and pressure head distributions, and subsurface flow contributions to stream discharge. The conceptual model relies on a topographic index to predict saturation excess runoff and on Philip's infiltration equation to predict infiltration excess runoff. The numerical model solves the three-dimensional Richards equation describing flow in variably saturated porous media, and handles seepage face boundaries, infiltration excess and saturation excess runoff production, and soil driven and atmosphere driven surface fluxes. The study catchments (a 7.2 sq km catchment and a 0.64 sq km subcatchment) are located in the North Appalachian ridge and valley region of eastern Pennsylvania. Hydrologic data collected during the MACHYDRO 90 field experiment are used to calibrate the models and to evaluate simulation results. It is found that water table dynamics as predicted by the conceptual model are close to the observations in a shallow water well and therefore, that a linear relationship between a topographic index and the local water table depth is found to be a reasonable assumption for catchment scale modeling. However, the hydraulic equilibrium assumption is not valid for the upper 100 cm layer of the unsaturated zone and a conceptual model that incorporates a root zone is suggested. Furthermore, theoretical subsurface flow characteristics from the conceptual model are found to be different from field observations, numerical simulation results, and theoretical baseflow recession characteristics based on Boussinesq's groundwater equation. |
| File Size | 1226232 |
| Page Count | 14 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19940011558 |
| Archival Resource Key | ark:/13960/t70w3db3q |
| Language | English |
| Publisher Date | 1993-01-01 |
| Access Restriction | Open |
| Subject Keyword | Earth Resources And Remote Sensing Seepage Structural Basins Scale Models Soil Moisture Pressure Heads Saturation Hydrodynamic Equations Water Flow Water Balance Precipitation Meteorology Drainage Topography Boussinesq Approximation Mathematical Models Infiltration Water Tables Hydrology Models Ground Water Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
