Trellis Drainage Patterns

08/31/25

“How do grid-like rivers form?”

Drainage pattern shapes form based on the local geology. Sometimes, the surface might have alternating bands of resistant and non-resistant rock. When water flows over these surfaces, the non-resistant rock erodes more steadily and turns into a valley between the resistant rock bands. The main tributaries of these rivers will run through these valleys and form perpendicular streams down the edges of the ridges of the resistant layers. These Trellis Drainage Patterns are prone to flooding because the water flowing through the valleys can overflow during heavy rains. Bakudabakek/Wekwabegituk (also named “The Bay of Fundy” by the settler-colonial state of Canada) is an example of a trellis drainage pattern.

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• Earth/Climate science
• Urban Systems