Since MODFLOW computes cell-based groundwater mass-balances to achieve its solution, it is instructive to examine the grid boundary fluxes of the best-fit steady-state solution. In this case, we are interested in the mass balance for the alluvial aquifers (Layers 1 & 2, or Qt and Qal). Figures 22-23 depict the total mass flux into and out of the alluvial layers.
Figure 22: Total recharge to top of
model (
).
Figure 23: Total vertical flux from
Layer 3 (), showing vertical leakage into the base of the
alluvial aquifers (primarily Layer 2) for each cell. These total
fluxes can be converted to areal averages by dividing by cell
surface area (
m
). Outline of alluvial sediments
(Layer I and II) and Hays city limit shown by white lines. Location
of modflow boundary conditions included, note correlation of central
upflow areas beneath well cells.