Riprap (in North American English), also known as rip rap, rip-rap, shot rock, rock armour (in British English) or rubble, is human-placed rock or other material used to protect shoreline structures against scour and water, wave, or ice erosion.

Is it riprap or Riff Raff?

The rusty, dilapidated cars sometimes seen piled up against riverbanks are not just eyesores; they are also a form of erosion control. And they have a name: Detroit Riprap, according to the website Amusing Planet.

What is riprap?

Riprap is a permanent layer of large, angular stone, cobbles, or boulders typically used to armor, stabilize, and protect the soil surface against erosion and scour in areas of concentrated flow or wave energy.