出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/05/22 20:25 UTC 版)
A Riffle is a short, relatively shallow and coarse-bedded length of stream over which the stream flows at lower velocity and higher turbulence than it normally does in comparison to a pool. As a result of the lower velocity and heightened turbulence, small ripples are frequently found. Riffles are usually caused by an increase in a stream bed's slope or an obstruction in the water.
burls
rudds
駆けくら
a plaything with which one trifles for pleasure
ぐぐれ