Hydro-Enforcement vs. Free Flow
Updated September 13, 2024
This article applies to:
- Terrain 3D
- Terrain Forestry
- RoadEng Civil
- RoadEng Forestry
Hydro-Enforcement Vs. Free Flow
The hydro-enforcement functionality provides a fast and easy solution for allowing flow through the topo surface and/or forcing flow uphill if needed. This uphill functionality is an extremely useful tool for quickly addressing surface imperfections and conditions such as pumping water out of a depression.
However, hydro-enforcement forces flow to follow the direction of the hydro-enforcement feature and does not allow for "free flow" through the feature.
In most cases, the direction of flow is obvious or can be quickly determined with two iterations: try the hydro-enforcement feature in both directions and see which result makes sense. However, if you have hydro-enforcement features in flat but complex terrain with significant ponding, the appropriate direction may not be obvious. In such cases, you can modify the topo surface on which you are running the hydrology tools to allow for free flow through the topo.
When doing this, it’s important to consider that hydrology tools use a regular grid rather than a TIN surface. The surface should be modified to accommodate the “cell size” used in the hydrology calculations.
| TIN Surface | Cells Grid |
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The video below provides further explanation and a workflow.