渓 means mountain stream and is a JLPT N1 kanji. It has 11 strokes and uses the water (three drops) radical (氵).
Stroke order · 11 strokes
On'yomi (音読み)
ケイ
Kun'yomi (訓読み)
たに、たにがわ
Radical
氵 · water (three drops)
Strokes
11
How to remember 渓
Water (氵) carving its way through the mountains — a mountain stream path. 渓谷 — touring valleys during the 紅葉 (autumn leaves) season is a Japanese classic!