Benchmark of Result Between Stormwater Module in MiTS 3 and EPA SWMM

To get a matching result between the Stormwater module in MiTS 3 and EPA SWMM, the project’s design must be similar. In this benchmark, we are designing a detention pond. Several conditions must be met for the results to match:

1. We must design, analyze and save the detention pond in the Stormwater module first, then export it to the EPA SWMM file

2. Verify that both software have similar default values for analysis [routing method, routing steps, flow unit]

3. In the Stormwater module, make sure to analyze as ‘Analysis’, not as ‘Design’

Checking default values for Stormwater and EPA SWMM #

How to check/adjust the value used in each software. Refer to the table below;

Default	StormWater	EPA SWMM
Flow unit[LFS]	Input > Inflow Source (Tabular Flow) > Node Inflow > Tabular	Ribbon tab > Project > Defaults… > Nodes/Links > Flow Units
Routing method[KINWAVE]	Input > Project > Analyse > Flow Routing Method	Ribbon tab > Project > Defaults… > Nodes/Links > Routing Method
Routing steps[60s]	Input > Project > Analyse > Routing Steps	LHS Panel > Project > Options > Time Steps > Routing Step

Example #

Stormwater module Project File

EPA SWMM Project File

Design #

Inflow Hydrograph #

2 Years ARI

50 Years ARI

100 Years ARI

The inflow hydrograph between the Stormwater module and EPA SWMM is similar to each other. This is because we are using the same hydrograph data.

Storage Time Series #

2 Years ARI

50 Years ARI

100 Years ARI

The inflow hydrograph and outflow hydrograph from both Stormwater module and EPA SWMM are similar. However, there is one graph that is different in value but has a similar shape which is depth/storage over time. This is because the two calculate different measurements. The Stormwater module calculates the depth of the pond which is in length (m) while EPA SWMM calculates the storage of the system which is in volume (m³)

Drain and Node Summary Result #

Conclusion #

In conclusion, the results obtained from both software are similar. Both Stormwater module and EPA SWMM have the same value of maximum depth in nodes and maximum flow in nodes and drains.

This provides us with assurance that our Stormwater module produces accurate outcomes.