This tab displays the current settings in the Property Editor for calculation options. To change this, click Analysis > Calculation Options and change the settings in the Property Editor.

The Calculation Options tab displays the following information:

Maximum Network Traversals: This is the maximum number of iterations that will be performed to achieve the closest approximation of the desired network results.

Flow Convergence Test: This value is taken as the maximum relative change in discharge occurring at the system outlet between two successive network solutions. In rational hydrology, the system discharge is a function of travel time as well as the hydraulics throughout the system. Therefore, it is necessary to iterate until the system balances, or a maximum number of trials has occurred.

Neglect Side Flow?: Allows you to choose whether to neglect side flow into a grate inlet opening. If you select True for this option, only those approaching flow interfacing with the front of the grate will be included in the inlet calculations.

Neglect Gutter Slope for Side Flow?: If this option is True, the software will neglect the gutter cross slope and always use the road cross slope for side flow calculations. If this option is False, and the grate width is less than the gutter width, the software will use the gutter slope for side flow calculations.

Active Components for Combination Inlets In Sag: This section gives you the choice of whether to use both curb and grate openings, just the grate, or just the curb opening for combination inlets at an in sag location.

Active Components for Combination Inlets on Grade: This section gives you the choice of whether to use both curb and grate openings, just the grate, or just the curb opening for combination inlets at an on grade location.

Flow Profile Method: Allows you to choose either a Backwater Analysis or a Capacity Analysis type of gradually varied flow computational scheme.

Number of Flow Profile Steps: The gradually varied flow profile divides each pipe into internal calculation segments within the shooting-style iterative calculation method for the link's variable hydraulic grade line. The default value of profile steps is five, and it is recommended that the value entered here be at least five for accuracy. Incrementing this number will improve the accuracy of the hydraulic grade calculation, but will also increase the calculation time.

Hydraulic Grade Convergence Test: The value entered here is taken as the maximum absolute change between two successive iterations of hydraulic grade at any junction or inlet in the system. For a given discharge, the upstream propagation of headlosses through pipes will continue until two successive calculations change by an absolute difference of less than this test value.

Hydraulic Grade Convergence Test: The value is used in the standard step gradually varied flow profiling algorithm. The calculations is assumed to converge to the solution when the two successive depth iterations are within this absolute test value.

Average Velocity Method: The selected method used to calculate the average velocity in a hydraulic link. This average velocity is then used to compute travel time of flow within the hydraulics links of gravity subnetworks. There are four available options: Actual Uniform Flow Velocity - The velocity of a link will be computed based on the governing uniform flow depth, determine for the hydraulic conditions of the pipe; Full Flow Velocity - The velocity of a link will be determined assuming a (maximum depth) full flow condition; Simple Average Velocity - The velocity is the average of the two velocities computed with the upstream and downstream depths of the link; Weighted Average Velocity - The velocity is average of each gradually varied flow depth computed for the link by the backwater computational routine.

Minimum Structure Headloss: The minimum junction loss expected at each structure. If the system calculates a headloss at a structure that is lower than this value, the value specified in the Minimum Headloss field will be used.

Minimum Time of Concentration: The minimum Tc for the simulation. Time of Concentration (Tc) is defined as the amount of time it takes for water to travel from the farthest point in the watershed drainage area to an inlet. If at any point, the computed Tc is less than the optioned minimum value, the minimum value declared within the calculation options will alternatively be used within a calculation run