User's guide of Proceessing Modflow 5.0

Processing Modflow 211
6. Examples and Applications
The sample problems contained in this chapter are intended to illustrate the use of PMWIN and
the supported programs. The sample problems are described in following sections. Each section
deals with a specific theme. The models of each section can optionally be installed during the
installation of PMWIN. Except the tutorials, the description of each problem is divided into
three parts. They start out with Folder, where you can find the ready-to-run model, for example
\pm5\examples\tutorials\tutorial1\. Next, you’ll find a disccusion of the problem and finally
you will find the simulation results. Note that you should change the path \pm5\, if you have
installed PMWIN in an other folder.
6.1 Tutorials
6.1.1 Tutorial 1 - Unconfined Aquifer System with Recharge
Folder: \pm5\examples\tutorials\tutorial1\
Overview of the Problem
This simple scenario is designed to demonstrate the basic features of PMWIN and MODFLOW.
An unconfined aquifer (Fig. 6.1) is a coarse grained sand with a measured isotropic hydraulic
conductivity of 160 m/day, the specific yield has been assessed as 0.06. Recharge to the aquifer
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only occurs throughout the 4 month wet season at a rate of 7.5 × 10 m/day, outside the wet
season there is no recharge to the aquifer. The elevations of the aquifer top and bottom are 25 m
and 0 m, respectively. The area of interest is 10000m long by 6000m wide and is bounded by
“no flow” zones to the east and west. There is also a volcanic mountain in the south east corner
of the model area. To the north and south exist areas of constant hydraulic head with values of
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15 and 19m respectively. A total of nine wells in the area are each pumped at 45 l/s (3888 m /d)
during the 8 month dry season to supply water for irrigation and domestic purposes.
Your task is to assess the water levels in the aquifer under the following conditions:
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1. steady-state, with the mean recharge rate = 2.5×10 m/day, no pumping;
2. after 8 months pumping during the dry season; and
3. the degree of recovery of the water levels by the end of the following wet season.
6.1.1 Tutorial 1 - Unconfined Aquifer System with Recharge