To facilitate integration between the principle modules of the model, additional
data
handling utility packages were developed.
INTEGRATED MODELING DISCUSSION
When the FHM was originally developed, specific guidelines which restricted
the
capabilities of the model were mandated. First, was the requirement that
the model
run on a 286 computer with 640k of RAM. Also the model was developed under
the
premise that all modeling would be performed on "logical reclamation
units" (LRUs).
Typical LRUs are small (from 0.4 km or, 100 acres to 4.0 km or 1000 acres)
and
have simple hydrologic characteristics (one or two) catchments). Application
of the
original FHM was essentially limited to the LRU concept or extremely simple
natural
systems. As more and more sites were modeled with the FHM and as regulatory
agencies began to require a more comprehensive combined regional analysis,
it was
apparent that severe limitations in the model existed.
In the past three years research at USF has been supported by FIPR and others
to
maintain and modify the model to suit the needs of the FHM users. Adaptations
of
the model have occurred such that the FHM can be used for regional, impact
studies. Specifically, improvements include: increasing the number of basins
and
subbasins the model can handle in one application to 50, increasing the number
of
river reaches for flow routing to 50, increasing the allowable number of
grids in the
groundwater model, allowing for multiple outfalls (thus multiple river basins),
including all generic MODFLOW packages (e.g., wells, general head boundaries,
etc.), allowing off site inflows (thus partial basins), and providing for
greater flexibility
in user defined and/or multiple defined site specific rainfall. No longer
is the model
limited to LRUs of only a few square kilometers. The FHM can and has been
applied to study areas of several thousand square kilometers (see study site
below,
USF, 1994).
The area of interest in which research is currently directed is in the field
of multi-
scale modeling. This is where boundary conditions of smaller domain hydrologic
models are defined by the results of larger regional scale models. Multi-scale
modeling facilities simulating cumulative or larger stress effects to the
regional
watershed or aquifer while addressing near-field small scale effects such
as
evaluating the hydroperiod in an individual wetland. Maintenance of a regional
scale
model (at a public domain repository, e.g., DER, SWFWMD, or FIPR) will allow
mine reclamation engineers and hydrologists to apply the FHM using data from
the
regional model to set up the smaller scale models. More importantly, the
effects of
mining the individual LRUs can be simulated on the regional hydrologic model
and
not only the LRU. The accumulation of many minor impacts at the LRU scale
can
now be evaluated for the effect on regional hydrology.


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