Do contour U-turns point upstream or downstream?

Do contour U-turns point upstream or downstream?

• A. Upstream
• B. Downstream
• C. They have no fixed direction
• D. They point toward the drainage divide

Answer: (A)

Contour lines mark places of equal elevation and bend to reflect the shape of the terrain. When a contour line curves into a U around higher ground, the inside of the U sits on the higher ground, and the curve points toward that higher area. In a drainage system, that higher ground is toward the source, i.e., upstream. Water would flow downhill away from the inner high ground, so the open end of the U faces downstream. So contour U-turns point upstream.