Raindrops can fall at 20 miles per hour causing what is called "splash erosion" of soil. Soil erosion caused by rain is a major problem that costs businesses, individuals and governments money every year.

In agriculture alone water erosion causes an estimated $27 billion in on-site losses, and frequently causes economic losses downstream as well.

Rain splash is a powerful force that has sculpted the features of the mountains and cliffs of the world, particularly those in arid and semi-arid regions, researchers from Vanderbilt University and the University of Arizona said in a statement released Friday.

"A single drop is harmless, but when billions of raindrops fall from a cloudburst onto bare soil they strike like billions of tiny hammers, dislodging tons of soil per acre which is carried away by surface runoff," researchers said.

Researchers said they discovered that individual raindrops, which can travel at speeds of up to 20 miles per hour, can splash soil particles up to five feet horizontally and two feet into the air.

Splash erosion does the most damage on sloping surfaces, researchers said.

But soil erosion doesn't just affect farms. At an elementary school in Des Moines, Iowa, officials noticed that rain was eroding soil, mulch and river rock from the play areas and washing it onto the grass playfield.

School officials built a rain garden to catch rainwater as it ran down off the parking lot.

Rain gardens are depressed areas planted with flowers and native vegetation that soaks up rainwater so it can drain slowly into the ground. That prevents raindrops from splashing up and dislodging dirt and carrying it downstream.