SWMM 5.1 Update History - Build 5.1.008 (04/02/2015)

SWMM 5.1 Update History
=======================

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Build 5.1.008 (04/02/2015)
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Engine Updates:

New Features:
=============

1.  Monthly adjustments for hydraulic conductivity used for
    rainfall infiltration and for exfiltration from storage
    nodes and conduits was added.

2.  LID drains can now send their outflow to a different node
    or subcatchment than the parent subcatchment in which they
    were placed.

3.  Conveyance system Outfall nodes now have the option to
    send their outflow onto a subcatchment, to simulate
    irrigation or complex LID treatment options.

4.  A new LID practice, Rooftop Disconnection, has been added.
    It allows one to explicitly model roof runoff with an
    optional limit on the flow capacity of their downspouts.
    Disconnection is specified by setting the Return To Pervious
    Area field in the [LID_USAGE] section to 1. 

5.  An optional soil layer has been added to Permeable Pavement
    LIDs so that a sand filter or bedding layer beneath the
    pavement can be modeled.
    
6.  Several new built-in variable names can now be used in
    custom groundwater flow equations for porosity, unsaturated
    hydraulic conductivity, infiltration rate, and percolation
    rate. See the Help file for more details.

7.  A Groundwater Summary table has been added that reports 
    several groundwater statistics for each subcatchment.

8.  A new option, the Minimum Variable Time Step, was added that
    limits the smallest time step that can be computed under
    variable time stepping for dynamic wave flow routing. In
    previous releases it was fixed at 0.5 seconds which remains
    the default. The smallest value it can now have is 0.001 sec.

9.  The dynamic wave routing procedure was parallelized to take
    advantage of multiple processors, making it run several times
    faster. A new option, THREADS, sets the number of parallel
    threads to use, where the default is 1.

10. A new column was added to the Node Depth Summary report table
    that shows the maximum depth recorded at the Reporting Time Step
    so it can be compared to the maximum depth attained over all
    routing time steps also shown in the table.

11. Control rule premises can now contain conditions that compare
    the values of a node or link variable at two different locations
    (e.g. IF NODE 123 HEAD > NODE 456 HEAD) and node volume was
    added as a condition clause variable.

Improvements:
=============

12. When a subcatchment with LID controls receives runon from another
    source (e.g., a subcatchment, LID drain or outfall node) the
    runon is now distributed only across the non-LID area of the sub-
    catchment instead of the full area. If a single LID takes up the
    full subcatchment area then the runon is directed onto the LID.

13. Storage node HRT was added to the state variables saved in the
    Hot Start file.

14. The threshold value for reporting a non-zero runoff result
    was changed from 0.001 cfs to 0.001 inches/hr.

15. The calculation of overall flow routing mass balance was
    modified to account for cases where some flow streams, like
    total external inflow, are negative.

16. The "Surface Runoff" label in the Runoff Continuity Report was
    replaced with "Total Runoff" since the value reported consists
    of both surface runoff and LID drain flow.

17. The "Internal Outflow" label in the Flow Routing Continuity
    Report was replaced with "Flooding Losses" to improve clarity.

18. The pollutant washoff routines were moved to a new code module
    (surfqual.c) and revised to account for the reduction in
    pollutant load that results from runoff flow reduction by LID
    units.

19. Initial flows for Steady Flow routing are now ignored since they
    are not used in the routing calculation and the initial volume
    associated with them contributed to system mass balance error.

20. The various types of lateral inflows to conveyance system nodes
    are now evaluated at the date/time for the start of the routing
    time step instead of at the end of the time step.

21. The final runoff and routing time steps are adjusted to insure
    that the simulation's total duration is not exceeded.

22. When evaluating user-supplied math expressions, any NaN (Not a 
    Number) result (caused by an underflow, overflow or divide by zero)
    is set to 0 so that the NaN doesn't propagate through subsequent
    calculations.

Bug Fixes:
==========

23. The evaporation rates read from a time series would only change
    when a new day was reached (even though values at more frequent
    intervals were present) and could cause a run to stop pre-
    maturely in some rare cases.

24. The runoff read from a Hot Start file should have been assigned
    to a subcatchment's newRunoff property, not to oldRunoff.

25. An indexing bug that caused Hot Start files with snowmelt
    parameters to be read incorrectly was fixed.

26. The setting for a non-conduit link read from a Hot Start file
    was not being used to initialize the link.

27. A bug in adjusting snowmelt for snow covered area derived from
    an areal depletion curve was fixed.

28. Snowmelt should not have been included in the total
    precipitation reported for a subcatchment since the snowfall
    which produced it was already accounted for.

29. When computing a flow rate through the Drainage Mat of a Green
    Roof LID unit, the mat's void ratio was being applied to the
    water depth instead of to the mat's area.

30. The state of LID controls was not being considered when
    choosing to use the wet or dry runoff time step which sometimes
    lead to excessive LID continuity errors.

31. A re-factoring bug that left reporting time in minutes instead
    of hours in the detailed LID results file was fixed and results
    are now written to the file at each runoff time step where the
    state of the LID unit changes.

32. Failure to initialize groundwater evaporation loss to 0 was
    causing problems with the reported groundwater mass balance 
    for subcatchments that had no pervious area.

33. Excessive continuity errors for systems having conduits with
    large seepage rates was fixed.

34. Pollutant loss through seepage in conduits and storage nodes was
    not being included in the mass balance calculations.

35. Concentrations in conduits and storage nodes were not being
    increased to account for loss of water volume when evaporation
    was occurring.

36. Premature exiting of the routine that checks for capacity limited
    links whenever a non-conduit link was encountered was fixed.

37. A bug in identifying the percent of time that a conduit has either
    end full was fixed.

38. A re-factoring bug that prevented surcharged weirs (see Update 5
    for 5.1.007) from passing any flow was fixed.

39. A bug in evaluating recursive calls to nodal water quality treatment
    functions was fixed.


GUI Updates:

1.  The missing July - December column labels were restored on both
    the evaporation and wind speed tables in the Climatology Editor.

2.  The label "Surface Water Height (Hsw)" in the Groundwater Flow
    Editor was changed to "Surface Water Depth" to make clear that
    it is the depth of water at the receiving node and not the height
    of water above the aquifer bottom (or Hsw as shown in the dialog's
    diagram).

3.  The label "Channel Bottom Height (Hcb)" also in the Groundwater
    Flow Editor was changed to "Threshold Water Table Elev." to make
    clear that it is an elevation and not a height above the aquifer
    bottom (as Hcb is in the dialog's diagram).

4.  A Groundwater Summary table was added to the form that displays
    summary results tables.

5.  Groundwater upper zone soil moisture and node lateral inflow are
    now included in the abridged Hot Start file that the GUI can
    produce (using the File | Export | Hot Start File command).

6.  The column labels in the various sections of the SWMM input file
    generated by the GUI were modified to better match the labels used
    to describe the input file format in Appendix D of the Users Manual.

7.  A "Route To" field was added to the Outfall Node property editor to
    accommodate the new option of allowing outfall nodes to discharge
    onto a subcatchment.

8.  The Dynamic Wave page of the Simulation Options dialog was modified
    to include the new Minimum Routing Time Step option and the new
    Number of Threads option.

9.  The LID Control Editor was updated to include the new Rooftop
    Disconnection LID practice and the option to add a soil layer
    to the Permeable Pavement practice.

10. A Drain Outlet field was added to the LID Usage Editor.

11. The conduit Cross Section Editor dialog was enhanced to display
    a selectable list of standard size codes and their dimensions for
    elliptical and arch pipes.

12. Custom changes made to the Map's Legends are now saved with the
    rest of a  project's settings in its .ini file.

13. Word wrapping was added to the Title/Notes display in the
    Project Browser to make the contents easier to read.

14. Modal dialog message windows now appear centered over the form that
    generates them instead of in the middle of the full display screen.

15. The style of all dropdown list boxes was changed to make them more
    visually appealing.