A culvert is a structure that allows water to flow under a road, railroad, trail, or similar obstruction. They are often used for drainage purposes, constructed using materials like concrete, corrugated steel, or PVC.
A detention pond is a reservoir designed to temporarily hold a set amount of water while slowly draining to another location. Principally used for flood control when large amounts of rain could cause flash flooding.
A retaining wall is a structure designed to restrain soil to a slope that it would not naturally keep to (typically a steep, near-vertical, or vertical slope). They are frequently used in landscaping, construction, and flood prevention to prevent the erosion of soil and manage water runoff.
