User's guide of Proceessing Modflow 5.0

Processing Modflow 87
1. Recharge is only applied to the top grid layer.
2. Vertical distribution of recharge is specified in the Layer Indicator array I , which defines
RCH
the layer where recharge is applied.
3. Recharge is applied to the highest active cell in each vertical column. The user does not have
to predetermine the layer to which recharge should be applied. The appropriate layer is
automatically selected by the Recharge package. If the highest active cell is a constant-head
cell recharge will be intercepted and cannot go deeper.
Refer to the description of the Recharge package in McDonald and Harbaugh (1988) for an
example of using these options.
MODFLOW < Reservoir
The Reservoir package (Fenske et. al, 1996) is designed for cases where reservoirs are much
greater in area than the area represented by individual model cells. More than one reservoir can
be simulated using this package. The area subject to inundation by each reservoir is specified by
entering the reservoir number for selected cells. For reservoirs that include two or more areas of
lower elevation separated by areas of higher elevation, the filling of part of the reservoir may
occur before spilling over to an adjacent area. The package can simulate this process by
specifying two or more reservoirs in the area of a single reservoir.
Reservoirs are defined by using the Reservoir Package dialog box (Fig. 3.21) of the Data
Editor to assign the following values to the model cells:
- Reservoir Number I [-],
RES
- Land-surface elevation of the reservoir B [L],
RES
- Vertical hydraulic conductivity of the reservoir bed HC [L/T],
RES
- Thickness of the reservoir bed Rb [L], and
- Layer Indicator IRESL [-]
- Parameter Number [-].
The parameter number is used to assign HC as a parameter for an automatic calibration by the
RES
inverse models PEST or UCODE, see PEST < Parameter List... or UCODE < Parameter
List....
The elevation of the water table in reservoirs are specified by using the Stage-Time Table
of Reservoirs dialog box (see below). The land-surface elevation within the specified area of
potential inundation for each reservoir is typically defined by the average land-surface elevation
3.6.1 MODFLOW