In a topographic map, why would a lake or body of water not have any contour lines on its surface?

Contour lines do not show up on a lake or a body of water because each line corresponds to a specific elevation, and contour lines never cross each other such as mountains and valleys. COntour lines that are in topographic maps are imaginary lines that connect different point of equal elevation above a reference level, which usually means at sea level.

Yep, we’re not gonna last that long sadly