Flow Shape and Direction: Weathering's Indirect Role

Weathering does not directly determine the shape and direction of flows (rivers, streams, lava, etc.). Instead, these are governed by:

• Topography - Slope, elevation changes, landforms
• Gravity - The fundamental driver of downhill flow
• Geology - Rock hardness, structure, fault lines
• Climate - Precipitation patterns, freeze-thaw cycles
• Vegetation - Root systems, ground cover affecting erosion
• Human modifications - Channels, dams, diversions

Weathering's Indirect Influence

Weathering (chemical and physical rock breakdown) shapes the landscape over geological time, creating the topography that subsequently guides flow patterns. It influences sediment supply, valley formation, and substrate permeability—but doesn't directly control active flow direction or channel geometry.

Think of weathering as the sculptor creating the canvas, while gravity and hydrology paint the flowing lines upon it.