New Storm Event Scenarios Summary

The summary is displayed immediately following the completion of the creation of storm events, alternatives, calculation options and scenarios. The summary displays the statistics of each along with the elapsed time.

The default base calculation options, base rainfall runoff alternative and base scenario were manually deleted. Otherwise, these items are not modified other than creating additional scenarios, calculation options and alternatives.

How the Different Pieces are Created

• Create Calculation Options
  • There is a calculation option created for each unique duration selected in the wizard.
  • The simulation duration is calculated by multiplying the simulation duration multiplier by the storm event duration.
  • The label of the calculation option includes the selected solver, the duration of the storm event and the simulation duration.
  • e.g. A calculation label is generated as “Explicit (SWMM Solvers) - 6 hours storm duration; 12 hours simulation duration”

    An example set of calculation options generated:

    

• Creating Rainfall Runoff Alternatives
  • For each storm event generated, a corresponding rainfall runoff alternative is also created.
  • For each unique return period selected, a base rainfall runoff alternative is created.
  • Subsequent alternatives of the same return period with different storm durations are created as children of that base scenario.
  • The label of the storm event profile is included in the label of rainfall runoff alternative along with the return period and storm duration.
  • e.g. A rainfall runoff alternative’s label is generated as “2 years 50% Summer Profile Storms - 6 hours”.

    An example of the base rainfall runoff alternatives created:

    

  • If climate change is considered, the Climate Adjustment Type set to constant the appropriate value is set to the climate adjustment column.
  • If the climate change factor is 0%, or climate change is not considered, then the climate adjustment type is set to None for the alternative.
• Creating Storm Events
  • For each unique return period and storm event profile, a storm event group of the selected type is created. For each group, a storm event for each unique duration is created.
  • If climate change is considered, an additional storm event is created adding the specified factor to the base depth of that storm event.

    Storm event groups are created for each unique return period and storm event profile.

    

• Creating Scenarios
  • For each unique return period and storm event profile, a base scenario is created.
  • Subsequent child scenarios using the same return period and storm event profile but different durations are then created.
  • Alternatives and calculation options are automatically assigned.
  • Each scenario has its own rainfall runoff alternative assigned as each rainfall runoff alternative has a unique storm event assigned to it.
  • The scenario label includes the return period, the storm event profile label and storm event duration.
  • If climate change was considered, the label also includes the additional climate change added.

    A typical set of scenarios generated by the wizard:

    

• Additional Alternatives
  • If the option of creating additional alternatives was used, then an alternative of the specified type for each unique profile is created.
  • The first unique profile is created as a base alternative.
  • Subsequent child alternatives are created for each additional unique storm event profile.

    Additional hydrology alternatives created per unique storm event profile:

    

  • For each scenario using the corresponding storm event profile label, the appropriate alternative is assigned. Child scenarios automatically inherit from the base scenario.
  • For example, the “50% Summer Profile” hydrology alternative is assigned to the base scenarios
    • 2 years – 50% Summer Profile – 6 hours
    • 4 years - 50% Summer Profile - 6 hours
    • 5 years - 50% Summer Profile - 6 hours
    • 10 years - 50% Summer Profile - 6 hours
    • 20 years - 50% Summer Profile - 6 hours
    • 25 years - 50% Summer Profile - 6 hours
    • 30 years - 50% Summer Profile - 6 hours
    • 50 years - 50% Summer Profile - 6 hours
    • 75 years - 50% Summer Profile - 6 hours
    • 100 years - 50% Summer Profile - 6 hours
    • The children of each of these base scenarios inherit its parent’s hydrology alternative.
  • The “75% Winter Profile” is assigned to the corresponding Winter Profile base scenarios.
  • You can change the default generated label to anything you want.