ICM InfoWorks - 🌊 Runoff Surfaces

 

🌊 Runoff Surfaces

📌 Overview

Runoff Surfaces in the InfoWorks network are linked to each subcatchment through Land Use, with up to twelve surfaces for every subcatchment.

🏞️ Categories of Runoff Surfaces

1. Impervious (e.g. roads 🛣️ or roofs 🏠)
2. Pervious (e.g. grass 🌱)

For every surface type, unique traits can be set determining how rainfall runoff happens, the volume of runoff, and its entry rate into the drainage system 🌧️➡️🚿.

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⚠️ Runoff Modelling Restrictions

📜 Key Restrictions:

1. All surfaces within a land use must employ the same runoff routing model 🔄.
2. If using the New UK (Variable) PR runoff volume model:
   • It has to be the last surface defined for a land use 📌.
   • The Default area for the final surface in the land use should exceed 0. If it's 0, the simulation engine ignores it. Hence, we suggest setting the Default area to 0.001 instead of 0 📏.
3. For the Green-Ampt runoff volume model, it should be the last surface pinpointed for a land use 🌱➡️📌.
4. In case the Wallingford (Fixed PR) runoff volume is employed on a surface within a land use:
   • All surfaces in that land use should adopt the Wallingford (Fixed PR) runoff volume model 🔄📏.