When water washes down a hill, picking up speed, it can cut tiny channels in the soil. These are called “rills.”
How small are rills? Well…some of them are just the right size for an ant to float along on a tiny inner tube. Some rills are less than 1 inch wide, while other rills are more than 1 foot wide.
When rills form, moving water builds up enough power to bust loose soil particles. Raindrops are no longer the only force that breaks the soil loose.
Heavy rains have dug out a network of tiny channels, known as “rills.”
Photo: USDA NRCS