Hydrology SWMM Routing in ICM SIM

Thanks all for your feedback on modifying the ICM routing to match SWMM networks. Rather than adding a new option we have changed the behavior of ICM SIM to match SWMM. This is available in 2024.4 and above (note database update required!).

Thank you Bob for clarifying the ideas. We all would love to have the SWMM5 hydrology equipped in InfoWorks ICM (SIM) and the user will have sole choice implementing what suits the region and standard belong to achieve a success modeling and deliverable. Also that will adding more value to the Infoworks ICM.

An image of the two options discussed in the idea

There are two distinct routing methods described in this Idea:

1. Impervious to Pervious Internal Routing:

   • Rainfall hits an impervious surface, producing "runon."

   • This runon, combined with direct rainfall, impacts the pervious surface.

   • The pervious surface then produces "runoff" and allows some water to infiltrate the ground.

   • The runoff from the pervious surface contributes to the lateral inflow, which then proceeds to a node.

2. Direct Routing:

   • Both impervious and pervious surfaces receive direct rainfall.

   • Each surface produces its own runoff, with the pervious surface also allowing for infiltration.

The runoff from both surfaces combines to form the lateral inflow, which then leads to a node.

a little diagram to further explain this

Impervious to Pervious Internal Routing

Rainfall Rainfall + Runon
↓ ↓
------------------- -------------------
| Impervious | | Pervious |
| | | |
------------------- -------------------
↓ ↓ ↓
Runon Runoff Infiltration
↓
Lateral Inflow
↓
Node

Direct Routing

Rainfall Rainfall
↓ ↓
------------------- -------------------
| Impervious | | Pervious |
| | | |
------------------- -------------------
↓ ↓ ↓
Runoff Runoff Infiltration
↓ ↓
+--------------------+
↓
Lateral Inflow
↓
Node