Gully Erosion (Geography) and Gully Trap (Civil)

Gully Erosion is an advanced and severe form of soil erosion.

• How it happens: When heavy rainwater flows rapidly down a slope over bare, unprotected soil, it cuts deep, V-shaped or U-shaped channels into the ground. These deep channels are called 'gullies'.
• Impact: Once gullies form, the land becomes highly uneven, fragmented, and completely unfit for agriculture. Such useless, deeply cut lands are known as Badlands.
• Famous Example: In India, the famous 'Ravines of Chambal' (चंबल के बीहड़) in Madhya Pradesh are the biggest example of severe gully erosion.

A Gully Trap is a plumbing basin placed in the ground outside a building, covered with a metal grating.

• Function: It collects wastewater from the kitchen, bathroom, and rainwater pipes before sending it into the main underground sewage drain.
• How it works: It contains a 'water seal' (a curved pipe that holds a little bit of water at all times). This water seal blocks the foul, smelly gases and insects from the main sewer from coming back up and entering your house.