Simulation and Design in one package
Computer programs for stormwater management can have various
objectives.
- simulation and analysis
- design of facilities
- detailing and drafting
Many programs are concerned with the first of these with some
facility for trial and error design.
Of
the programs used for computer aided drafting, the Hydrology module of
Softdesk is one but uses simple procedures for hydrology
simulation.
MIDUSS offers a blend of simulation and design. It provides
powerful decision support system for the sizing, design and evaluation
of stormwater management facilities for quantity control.
MIDUSS has been around since 1984. Even before this date it was
used for teaching civil engineering students the fundamentals.
It has always been a combination product - Simulation AND Design.
It is our philosophy that the two cannot be effectively separated.
The MIDUSS roots are in education and this theme has continued over
the nearly 20 years. The software strive for ease of use and
flexibility so that the engineer can applies their skills efficiently
and effectively.
Part of the MIDUSS name is the "I" for interactive. Back in
the early days most programs were batch oriented - but not MIDUSS.
In keeping with its desire for ease of use and efficient design it has
always been fully interactive.
Interactive means that you design the network as the peak
flow goes downstream. Each component can be optimized because
you "interact" with the program so that the flow is conveyed
in an efficient design. MIDUSS constantly provides you with feedback on how the design is going. If a pipe is surcharged,
you will be told and encouraged to change the design.
The drainage network is represented as a tree of N nodes connected
by (N-1) links representing conveyance, detention or diversion
devices. Each node represents a point at which runoff may be
introduced. Since the network is a spanning, non-circuited tree, nodes
can have any number of inputs but only one output.
For a given rainfall event, the solution takes the form of a
marching solution which moves downstream computing flow hydrographs
for the entire time-horizon at successive stations or nodes. At
junctions, the accumulated hydrograph is stored to allow other
tributary branches to be processed. When the flow from all
contributing branches has been computed the solution continues
downstream towards the root of the tree or outflow point
Some programs, such as EXTRAN, use a time-wise marching solution
which has the advantage of taking into account the potential effect of
backwater on the capture capacity of a minor system.
On the other hand, the downstream marching solution used in MIDUSS
allows the program to be completely interactive, letting you work
downstream in a logical fashion not unlike the approach taken in the
old rational method. At each location in the network, yuo can see the
entire hydrograph and gauge the extent to which runoff simulation is
reasonable and also the effectiveness of proposed design elements in
the drainage network in achieving the objectives of stormwater
management. Errors can be corrected or design decisions refined before
the results are transmitted downstream..
At the end of the design, you can easily apply a different
storm to your designed network. Problem areas of the design can be
identified and corrected easily. You do this
interactively in what we call Automatic Mode - a simulation process
which allows momentary stopping of the simulation to correct or anayze
a particular part of the design. Once reviewed, the simulation
continues to the end of the design.
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