This tutorial is a class exercise at Arba minch university, Ethiopia to show postgraduate students how to build, run and import/export a MODFLOW model using ModelMuse GUI.
Problem for the tutorial
The problem we will be solving in this tutorial is a Basin. The model grid will be discretized uniformly to 100 m. Assume the elevation of the top and bottom of the aquifer will be flat.
DRN Package: use the river shapefiles attributes field values for elevation and bed conductance
RCH Package: Recharge rate = 3.80E-9, recharge location= Top active cell
EVT Package: EVT Rate = 3.17E-8, EVT surface =Model Top, EVT depth = 0.5, EVT location=Top layer
4 aquifer layers:
Model_ Top (0 m),
Alluvial (ModelTop-15 m),
Layer 2((Model_Top – 100m) * 0.85))
Layer 3(Model_Top – 300m)
Layer 4 =800 m
Variable Horizontal Hydraulic Conductivity of, 5E-5, 5E-7, 8E-8, 1E-8 from the 1st to 4th layer and assume Isotropic aquifer.
Aquifer type: The last aquifer is confined and the others are convertible
In this MODFLOW Exercise you are provided the following spatial datasets:
- A polygon shapefile of the Basin, called Basin.shp
- A line shapefile of the river, called River.shp
MODFLOW Initial head = 200m
- Run a steady state model using no flow boundary and find the distributions of hydraulic head at the end of the steady state period. Was the budget converging with acceptable limit?
- Run the model by assuming a GHB at the south of the study area. Compare the results with 1. Use a constant boundary head 200 m and conductance of 0.002.
Input files link to download