Riprap
A foundation or sustaining wall of stones or chunks of concrete thrown together without any order.
Or
A layer of stones or chunks of concrete or similar material on an embankment slope to prevent erosion is called riprap.
Reference : Meriam webster dictionary
I love it. We have been studying ways to prevent erosion in our Earth science class and this is not a common concept to be considered but I will begin using it in class!
Absolutely love it!