Explanation:

Splash: loosening & splattering of small soil particles caused by raindrops impacting a wet soil surface
Sheet or interrill: removal of thin layer of soil over an entire soil surface caused by water flowing across soil surface
Rill: occurs during/after rain or when snow melts, & involves concentration of flowing water into small channels (<0.3 m) that are more turbulent & have greater scouring action than sheet flow turbulent & have greater scouring action than sheet flow
Gully: in areas steeper slopes, flow of water from rills concentrated,forming deep channels.