Swales vs berms

One-line orientation

Swale and berm are the two basic earth-shaping moves for managing site water, and the exam tests them as a pure opposite pair — one is a channel down, the other is a mound up.

Key points

• Swale: a shallow ditch / depression that guides water away from structures to prevent flooding; it can also let water infiltrate along its length. It conveys — water moves through it.
• Berm: a raised mound of earth that diverts or blocks water flow; it also screens views or headlights and adds aesthetic interest. It’s a barrier — water is steered around it.
• They pair up: use swales and berms together to manage water while keeping the natural flow and grade of the site.

Confusions / comparison

	Swale	Berm
Shape (section)	Depression — concave, down	Mound — convex, up
Does what to water	Conveys / infiltrates	Diverts / blocks
Extra role	(drainage only)	Screens views, headlights, wind
Water moves	Through / along it	Around it

Related

→ Site slopes (this module): the grades these elements drain · Runoff strategies (this module): bioswales as a vegetated, filtering variant of the swale · Detention vs retention (this module): where the conveyed water ends up.