This guide explains how to read Storm Sync Time Area graphs and reports, interpret the isochrone-strip display, and export analysed inflows. Set up the storm, bands, and loss model in the Storm Sync Time Area hydrology guide.

Review Hydrology Graph Results #

After completed analysis, go to Output ribbon and click Graph (in the Hydrology Section) to view hydrology graph.

Design Storm #

Two graphs are available under Design Storm: Rainfall Hyetograph and IDF Curve

Rainfall Hyetograph plots the rainfall intensity over time based on the selected temporal pattern. In a real Time Area run, this graph’s rainfall matches the rainfall intervals used for each catchment. Use the Design Storm Hyetograph Settings grid (RHS) to select the ARI and storm duration to display. Hover cursor at each rainfall block to view the storm interval (\Delta t), rainfall intensity, rainfall depth and temporal pattern fraction.

IDF Curves plots the IDF curve of each analysed ARI based on the IDF source selected. Each data points indicate the rainfall intensity at every analysed storm duration; its rainfall intensity multiplied by the \Delta t gives that storm’s rainfall depth. Running the analysis using RationalHydrograph analyses also display the IDF Curves, but without the hyetograph. In Design mode, the same graph draws the design ARIs’ curves with each drain’s design point at its time of concentration and rainfall intensity.

Rainfall Hyetograph of selected ARI and storm duration

Analysis Mode: IDF curves, with the analysed-storm point on the curves

Design Mode: IDF curves, with each drain plotted at its time of concentration and corresponding rainfall intensity.

Catchments #

Two graphs are available under Catchments: Rainfall Excess and Runoff Hydrograph

Rainfall Excess chart displays separate pervious and impervious panels. Each interval shows the rainfall excess and applied rainfall loss as stacked values; together, their heights equal to the total rainfall depth of the \Delta t. Rainfall Excess chart is available for Time Area results only.

Runoff Hydrograph chart shows the resulting catchment flow over time. Use the ARI / Storm Duration checklist at the RHS to select and compare multiple storm events. Runoff Hydrograph is available in TimeArea and RationalHydrogrpah method. RationalSteady produces one design flow and therefore has no hydrograph.

Rainfall Excess Histogram of selected ARI and storm duration in pervious and impervious areas

Runoff hydrograph of selected ARI and storm duration

Read the Catchment Hydrology report #

In Output ribbon, open Textual Report under Hydrology section. The report records the selected loss settings and interval-by-interval rainfall, loss, excess, and band contributions.

• Compact: Shows the peak-flow summary and runoff hydrograph with a simplified calculation summary.
• Detailed: Includes the full calculation working for each rainfall interval.

Use the Catchment and ARI selectors at the RHS tab to view the results for different catchments and design storm events. Failed scenarios are labelled and are not selected as the default usable result. For Horton infiltration, the Detailed report also includes the integrated infiltration for each interval and the Horton parameters used in the analysis.

Export the hydrology results to Excel #

In Output ribbon under Hydrology section, click Excel to view hydrology results in excel format. Two sheets will be opened: Catchment Result and Rainfall

• Catchment Result: Lists the results for each catchment under the selected ARI and storm duration. Use the result selector at the RHS tab to view results for a different ARI or storm duration.
• Rainfall: Lists the rainfall information for each analysed ARI, including the IDF source, its coefficients and the temporal pattern used in the analysis.

Catchment result sheet

Rainfall sheet

Understanding the isochrone strips #

The Isochrone Strips overlay is an illustrative display of the configured bands, but does not represent actual runoff travel-time delineation derived from terrain data.

MiTS generates the strips by creating cuts perpendicular to the catchment’s single Overland Flow line (line from within the catchment pointing to a drain). Each strip represents a band and is sized according to its fraction of the total band area. The strips collectively cover the catchment boundary. For concave catchments, a single isochrone band may appear as multiple disconnected areas due to the catchment boundary shape. These areas still represent the same band.

The strip geometry does not change the saved band areas or affect runoff calculations. It does not use terrain elevations or calculate flow paths. To display the band strip,

Click Catchment button, then select Isochrone Strips or Strips + Legend. Each colour represents a band’s travel time. To customise the colour palette and legend scale, go to Options → Project Settings → Storm Design → Detailing → Time Area Isochrones.

Export an EPA SWMM .inp file #

The export dialog offers two inflow sources:

• Generate from current settings: Recalculates the selected ARI and duration from the current project settings.
• Use saved analyzed inflows: Uses the node inflow hydrographs saved with the selected completed analysis. The open project’s network, storage geometry, and hydraulic settings still provide the EPA SWMM model structure. If saved inflow node marks no longer match the open project, restore the analysed project or export from current settings.

Choose the ARI, storm duration, mark handling, and output .inp file. Use the saved option when you need the analysed inflow ordinates; use current settings when you intend to generate a new hydrograph from current inputs.

Reference comparisons #

The numerical references are used to verify Storm Sync calculations against different rainfall-loss models. Refer to the following comparison and benchmark documents for the verification details:

• Refer to Storm Sync Time Area Comparison with MSMA2 Appendix 2.F2 for benchmark against decaying-rate loss model
• Refer to Storm Sync Time Area Comparison with Legacy PondCAD for benchmark against proportional loss model
• Refer to Storm Sync Time Area Horton Infiltration Benchmark for benchmark against Horton’s infiltration calculation

To attach link after finish the benchmark model