User's guide of Proceessing Modflow 5.0

178 Processing Modflow
to 1 at the top of the cell. When a particle is moved laterally from one cell to another, its vertical
local coordinate remains unchanged, regardless of how the elevations of the bottom and top vary
from one cell to another.
In MODFLOW, model layers of type 1 (unconfined) are always water table layers, model
layers of type 2 or 3 (confined/unconfined) are water table layers when the head in the cell is
beneath the elevation of the cell top. For water table layers, z is set equal to the head in the cell.
2
V x1
Starting point of particle 1
4.2 PMPATH Modeling Environment
V y2
Starting point of particle 2
V y1
exit points of particles 1 and 2
V x2
V x1 … V … 0
x2
V y1 … V … 0
y2
Fig. 4.4: Schematic illustration of the spurious intersection of two pathlines in a twodimensional
cell.
4.2 PMPATH Modeling Environment
The PMPATH modeling environment (Fig. 4.5) consists of the Worksheet, the cross-section
windows, the tool bar and and the status bar. They are described below.
Worksheet and cross-section windows
PMPATH as well as PMWIN use the same spatial discretization convention as used by
MODFLOW. An aquifer system is discretized into mesh blocks, or cells. An I, J, K indexing
system is used to describe the locations of cells in terms of rows, columns and layers. The I-, J-,
and K- axes are oriented along the row, column and layer direction, respectively. The origin of