Overview
The lecture explains how to apply rainfall, infiltration, and permeability models to 2D meshes in InfoWorks ICM, focusing on setup, model types, and integration with 1D systems.
Applying Rainfall to 2D Meshes
- Rainfall can be applied directly to a 2D mesh and specified spatially using multiple rainfall profiles.
- Direct rainfall is set through the "Apply rainfall directly to mesh elements" option in 2D zone properties.
- Rainfall can be applied everywhere, outside subcatchments, or based on specific spatial profiles.
- Avoid double counting runoff areas by careful assignment in integrated models.
Infiltration Models and Settings
- Five infiltration models are available: Fixed, Constant, Deficit and Constant Loss, Horton, and Green-Ampt.
- Infiltration surface 2D objects define infiltration for specific areas with unique surface types.
- Infiltration parameters vary by model (e.g., initial/limiting rates, decay factors, moisture deficits).
- Horton and Green-Ampt require setting initial soil moisture using a 2D initial condition zone.
Infiltration and Permeable Zones
- Infiltration takes place in set 2D zones or custom infiltration zone 2D objects.
- Infiltration zones should not have self-intersecting or hollow polygons.
- Permeable zone 2D objects connect infiltrated water from 2D surfaces to nodes, links, or subcatchments in the 1D system.
- Permeable zones can overlap several infiltration zones and help model flow within sustainable drainage structures.
Viewing and Managing Results
- Additional results fields (e.g., effective infiltration) are available for analysis.
- Rainfall percentage, evaporation, and infiltration model parameters can be customized per zone.
Key Terms & Definitions
- 2D Mesh — Grid representing the surface for rainfall and infiltration modeling.
- Infiltration — Process of water entering the soil from the surface.
- Fixed Infiltration — A set percentage of rainfall becomes runoff.
- Constant Infiltration — Fixed rate with an extra constant loss component.
- Deficit and Constant Loss — Single soil layer storage with evaporation and runoff.
- Horton Model — Infiltration calculated with initial and limiting rates, decay and recovery factors.
- Green-Ampt Model — Infiltration as a function of soil properties and moisture deficit.
- Infiltration Zone — Area with user-defined infiltration properties.
- Permeable Zone — Area that directs infiltrated water to a drainage system.
Action Items / Next Steps
- Set up rainfall and infiltration profiles for targeted 2D mesh areas as needed.
- Create, digitize, or import infiltration and permeable zones, avoiding self-intersecting polygons.
- Assign initial soil moisture for Horton and Green-Ampt models using 2D initial condition zones.
- Review infiltration and runoff results in graphs and grids for model validation.