Program Developments For Modeling Groundwater Flow In Three-Dimensional Heterogeneous Aquifers With MODFLOW And MODFLOWP.

摘要

This report documents (1) a number of stand-alone utilities to assist with input to MODFLOW and (2) code modifications internal to MODFLOW and MODFLOWP. These were developed to improve ease of use of MODFLOW and MODFLOWP for modeling groundwater flow in three-dimensional heterogeneous systems. Several utilities to assist with input to MODFLOW are specifically designed for use with the Goundwater Modeling System (GMS) pre-and post-processor package. New features for MOD FLOW include routines for: (1) assignment of material blocks and material types to these blocks within a given three-dimensional grid mesh; (2) generation of the Block Centered Flow (BCF) file for heterogeneous aquifers with material properties assigned to blocks, and with internal calculation of leakance and thickness-factored parameters (T, S); (3) distribution of pumping rate for individual model layers for a well that draws from or injects into multiple layers; (4) calculation of weighted draw down for an observation well screened over multiple layers; and (5) customizing the drawdown output file to contain data for a specified number of observation wells, rather than every node in the domain. For MODFLOWP, the program has been modified to: (1) simplify input by making the .PAR file free format; (2) allow the user to easily change the number and combination of parameters for estimation in a given run by modifying one line rather than regenerating the .PAR file; (3) automatically calculate ROFFs, COFFs,. and TOFFs for observation wells; (4) notify the user during program execution when lower or upper parameter ranges are exceeded; and (5) provide monitoring of run time.