Explanation:

Ravines

Rill erosion is the removal of soil by concentrated water running through little streamlets, or headcuts. Detachment in a rill occurs if the sediment in the flow is below the amount the load can transport and if the flow exceeds the soil's resistance to detachment.In rill erosion finger like rills appear on the cultivated land after it has undergone sheet erosion.These rills are usually smoothened out every year while forming. Each year the rills slowly increase in number become wider and deeper.