Simulating shallow tubewell drawdown in the Philippines using a three-dimensional finite difference groundwater model

Issue Date

1-2005

Abstract

A three-dimensional numerical groundwater model was developed using USGS-MODFLOW to simulate shallow tubewell drawdown in a typical aquifer system in the Philippines. The model was calibrated and validated under transient conditions using pumping and recovery test data. Model calibration yielded values of mean error, mean absolute error and root mean square error of -0.19 to -0.11 m, 0.11 to 0.19 m and 0.12 to 0.23 m, respectively indicating satisfactory agreement between simulated and observed drawdowns. Model validation also showed reasonable fit between observed and simulated values with a mean error, mean absolute error and root mean square error of 0.01 to 0.44 m, 0.02 to 0.44 m and 0.02 to 0.44 m respectively. Sensitivity analysis showed that the hydraulic conductivity of the coarse sand layer, where the pumped well screen is located, is the most sensitive parameter. Model simulations performed under various pumping scenarios indicate that significant well interference is induced at closer well spacing, increased discharge, depth and well screen and increased number of units pumping simultaneously. Simulation results could serve as basis for developing sustainable well installation and pumping strategies and for sound policy formulation on groundwater utilization in similar aquifer systems in the Philippines. © 2005 AAAE.

Source or Periodical Title

International Agricultural Engineering Journal

ISSN

8582114

Volume

14

Issue

4

Page

175-186

Document Type

Article

Language

English

Subject

Groundwater management, Numerical model, Shallow aquifer, USGS-MODFLOW, Well interference

Digital Copy

none

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