swale

A low tract of moist or marshy land.

A long narrow and shallow trough between ridges on a beach, running parallel to the coastline.

A shallow troughlike depression created to carry water during rainstorms or snow melts; a drainage ditch.

Bioswale, a shallow trough dug into the land on contour (horizontally with no slope), whose purpose is to allow water time to percolate into the soil.

The stored water creates an underground reservoir that aids plant growth for tens of feet below the swale. Swales also prevent gullies from forming by intercepting rainwater, slowing it, spreading it, and storing it in the soil.

A shallow, usually grassy depression sloping downward from a plains upland meadow or level vegetated ridgetop.

Jane climbed a few more paces behind him and then peeped over the ridge. Just beyond began a shallow swale that deepened and widened into a valley, and then swung to the left.

A gutter in a candle.

Alternative form of sweal (“melt and waste away, or singe”).