Selecting the Overland Flow tab allows the
user to set Manning's friction coefficients (n) for impervious and
pervious areas, depression storage depths, the percentage of
Impervious areas with no depression storage, and where Overland
Flow is routed, Pervious, Impervious or Outlet.
Selecting the
Options tab allows the user to enter
additional parameters needed by SWMM for analysis.
Sweep start and Sweep end are used reduce the accumulated
buildup of specific pollutants with street sweeping.
Dry Days is the number of days with no rainfall prior to the
start of the simulation.
Report Step is the interval for reporting of computed
results.
Wet Step is the interval for computing runoff during
rainfall and continuing until standing ponds and LID devices (Low
Impact Development) are dry.
Dry Step is the time step length used for runoff
computations when there is no rainfall or ponding and storage
devices are dry - essentially to compute pollutant buildup. Dry
Step must be greater than or equal to the Wet Step.
Routing Step is the time step length used for routing flows
and quality constituents through the conveyance system.
Lengthening Step is used with Dynamic Wave Routing to
artificially lengthen a conduit so that the travel time of a wave
is greater than this time step (Courant stability criterion).
Variable Step is a safety factor applied to variable time
steps computed using Dynamic Wave Routing.
Minimum Step is the shortest time step allowed when variable
time steps are used with Dynamic Wave Routing.
Inertial Damping is used to control inertial terms in the
Saint Venant momentum equation used in Dynamic Flow Routing.
Choosing
None uses these terms at all times,
Partial
reduces the terms as flow approaches critical and removes them when
flow becomes supercritical,
Fullremoves these terms from the
equation.
Normal Flow Limited specifies which condition is checked to
determine if conduit flow is supercritical and should be limited to
normal flow using Dynamic Wave Routing. Use Slope to determine if
water surface slope is greater than conduit slope. Use Froude
to check if the Froude Number is greater than 1 or Both to check
both conditions.
Minimum Surface Area is the minimum surface area used when
computing water depth changes under Dynamic Wave Routing.
Minimum Slope is the minimum slope allowed for a conduit.
Zero sets no minimum. SWMM uses a minimum of .001 ft drop during
computations.
Head Tolerance is the difference at each node between
successive trials. If the difference in head for a time step is
less than this value, the flow solution has converged.
Maximum Trials is the maximum number of trials allowed
during a time step to reach convergence when updating hydraulic
heads at the system's nodes.
Number of Threads allows the user to increase the number of
parallel processing threads used during Dynamic Wave Flow Routing
if the computer being used has multi-core processors installed.
Selecting the
Report tab allows the user
to specify the report date and time as well as to select the Report
Sections to be included.
The Export button exports an .inp file to
be opened in EPA SWMM software.
The Analysis button creates a report within Carlson software
for review and error checking.
The Analyze File button allows the user to open an existing
.inp file and displays the Carlson analysis report.
Exit closes the SWMM Actions dialog.
Pulldown Menu Location: Network
Keyboard Command: swmm
Prerequisite: SWMM version 5.1