Accession Number : ADA293825

Title :   Groundwater Model Parameter Estimation Using Response Surface Methodology.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Cotman, Richard M.

PDF Url : ADA293825

Report Date : MAR 1995

Pagination or Media Count : 116

Abstract : This thesis examined the use of response surface methodology (RSM) to estimate the parameters of a finite-element groundwater model. An existing two-dimensional, steady-state flow model of a fractured carbonate groundwater system in southwestern Ohio served as the calibration target data set. A Plackett-Burman screening design showed that only four of the ten hydraulic conductivity zones significantly contributed to the output of the finite-element model. Also, the effective porosity parameter did not significantly affect the model's output. Using only the four significant hydraulic conductivity parameters; four two-level, four-factor designed experiments were conducted to exploit the first-order response surface defined by a residual sum of squares function. Additionally, a central composite design and ridge analysis were used to adjust the four parameters and finally arrive at a calibrated model in a grand total of 146 runs. The final calibrated model, which had an average head elevation of 292 meters, matched the calibration target data set with a mean absolute error of only 7 mm over all 524 nodes of the model. RSM provided an effective calibration technique to estimate groundwater flow parameters. (AN)

Descriptors :   *MATHEMATICAL MODELS, *WATER FLOW, *FINITE ELEMENT ANALYSIS, *GROUND WATER, DATA BASES, COMPUTERIZED SIMULATION, EXPERIMENTAL DATA, PARAMETRIC ANALYSIS, PARAMETERS, OHIO, THESES, INPUT OUTPUT PROCESSING, POROSITY, MATHEMATICAL PROGRAMMING, ESTIMATES, REGRESSION ANALYSIS, FORTRAN, ERRORS, CALIBRATION, TWO DIMENSIONAL FLOW, ELEVATION, COMPUTER FILES, HYDRAULICS, STEADY FLOW, RIDGES, CARBONATES.

Subject Categories : Hydrology, Limnology and Potamology
      Operations Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE