How long does it take for a river to carve a gorge?

It depends on multiple factors like rock type, gradient, water flow, and sediment supply. Some gorges form in thousands of years (especially from catastrophic floods), while others take millions of years, but most develop over hundreds of thousands of years through repeated episodes of rapid cutting and long periods of stability.

What's the difference between a river gorge and a glacial valley?

River gorges are typically narrow with V-shaped or vertical walls and a stream channel at the bottom, carved by flowing water and sediment. Glacial valleys (troughs) are wider, U-shaped with rounded floors and smooth sides, sculpted by moving ice rather than water.

Why do some rivers carve deep gorges instead of spreading out?

Rivers carve gorges when they're forced to cut downward rather than sideways. This happens when they have a steep gradient, are confined by resistant rock on the sides, or when the land beneath them rises (tectonic uplift), giving them renewed cutting power focused on vertical erosion.

How the Hills Got Here

How Rivers Carve Gorges Through Rock

Fast-flowing water uses sand, gravel and boulders to wear away the bed and banks. Where a river is confined or drops steeply, continued erosion can cut a deep gorge through solid rock.

14 October 202610 min read