swmm-solver

Build 5.1.13 (Aug 2018)

Engine Updates:

1. A subcatchment's depression storage depth, its pervious surface roughness
   (Mannings n) and its hydraulic conductivity can now be adjusted on a
   monthly basis by assigning monthly time patterns to these properties.
   For conductivity, a subcatchment-specific adjustment pattern will
   override any project-wide set of climate adjustment factors.

2. LID controls can now treat a designated portion of a subcatchment’s
   pervious area runoff (previously they could only treat impervious area
   runoff).

3. Permeable pavement LID units subjected to clogging over time can now
   have their permeability only partly restored at periodic time
   intervals

4. The following options were added to control flow out of LID units
   through their underdrains:

   • A storage layer water depth above which a closed drain automatically
     opens.
   • A storage layer water depth below which an open drain automatically
     closes.
   • A control curve that specifies how the nominal drain flow rate is
     adjusted as a function of the head seen by the drain.

5. Pollutant removal percentages can now be assigned to LID processes that
   have underdrains. The removals apply to flow leaving the unit through the
   drain and not to any surface overflow from the unit.

6. The Subcatchment Runoff Summary Report now includes both pervious and
   impervious total runoff volumes (prior to any LID treatment) for each
   subcatchment.

7. A choice of method used to handle surcharging has been added to the list
   of Dynamic Wave options. The EXTRAN method continues to use the traditional
   Surcharge Algorithm to update the head at surcharged nodes. The new SLOT
   option attaches a Preissmann Slot to closed conduits flowing more than 98.5%
   full that eliminates the need to switch to the Surcharge Algorithm for
   surcharged nodes.

8. A closed vessel can now be modeled as a storage unit node that is allowed
   to pressurize up to a designated Surcharge Depth value. If this depth is 0
   then the unit is modeled as before as an open vessel.

9. A weir's discharge coefficient can now be allowed to vary with head across
   the weir by assigning it a Weir Curve (see Weir Properties). Weir curves
   tabulate coefficient values at specific head levels.

10. When the upstream offset of a regulator link is below the invert of its
    downstream node it is now automatically raised only for Dynamic Wave flow
    routing with a warning message issued. For other flow routing choices only
    the warning message is issued and no automatic offset adjustment is made.

11. Users can now choose to set a periodic time step for control rule evaluation.
    If this step is 0 then rules are tested as before at every routing time step.

12. The option was added to have time series results for a project's nodes and
    links be reported as average values computed over a reporting time step
    instead of being interpolated point values at the end of the reporting time
    step.

13. The following bugs were fixed:

    • Unused rain gages are no longer examined when adjusting the wet runoff
      time step.
    • The surface inflow rate to a permeable pavement LID unit is not allowed
      to exceed the pavement’s permeability.
    • The Minimum Nodal Surface Area dynamic wave routing option was being used
      as surface area always available at a node instead of an amount available
      only when the surface area of the node's connecting links fell below it.
    • The top width of a full closed rectangular cross section shape is now set
      to 0 since it can no longer supply any surface area.
    • The ‘C’ parameter value for a Mitered Corrugated Metal Arch culvert was
      corrected.
    • An incorrect reporting of flow continuity error for systems with backflow
      through outfall nodes was fixed.