Flow Saturation

Using surface water flow paths to display saturation gradients.

The FlowCatchment component uses the collection of pre-calculated flow paths to calculate the relative amount of surface infiltration across a given landform.

To do so, it takes the points that make up each of the flow paths and identifies the nearest segment of the mesh of surface. That segment then has a ‘volume’ of water added to it. Areas of the landform covered by many sets of flow paths will register as having a greater volume of water.

The precision of this volume is controlled by two parameters, The Start Volume parameter is a ‘budget’ of water that each flow path represents. The Segment Loss parameter is the rate of loss that occurs at each point within the flow path. So if a path begins with a Start Volume of 1000 and a Segment Loss of 0.1, each point within the path will add 10 to the nearest mesh/surface segment and subtract 10 from the volume assigned to that path. When the flow path ends it discharges all of the remaining volume (if any) at its end point.

Flow Saturation
Component
Nickname
Saturation
Panel
Hydro
Icon
Icon for the Saturation component

Identify the saturation levels across terrain given flow paths

Mode Name ID Description Optional Type
Mesh M Base landscape form (as a mesh) for the flow calculation MeshParameter
Flow Paths C The flow paths as generated by the flows component CurveParameter
Start Volume V The quantity of water that each path ‘starts with’ NumberParameter
Segment Loss T The decimal percent (e.g. 0.15 for 15%) of the initial volume that is lost in each segment NumberParameter

If Segment Loss is set to 0 then the Start Volume value will always be used at each point.

Image of the flow saturation component used across two hypothetical landforms
Grasshopper definition demonstrating how to use and extend the catchment analysis for Surface and Mesh forms.

Grasshopper definition demonstrating how to use and extend the catchment analysis for Surface and Mesh forms.

Philip Belesky, for https://groundhog.la