also: かてい
noun
Refers to the bottom of a river, stream, or watercourse.
川底の石がはっきり見えるほど水が澄んでいる。
The water is so clear that you can clearly see the stones on the riverbed.
Rare alternate spelling with on-reading; mostly seen in technical or older texts.
Compound of 川 (kawa, 'river') and 底 (soko, 'bottom'), with rendaku voicing of soko to zoko.