水

It is a pictograph that represents flowing water. The middle horizontal stroke symbolizes flowing water, and the strokes on both sides represent splashing water droplets.

As a side note, 川 (stream, river) also depicts flowing water but has evolved differently from 水.

Besides 삼수변, there are other water-related radicals like 물수부발 (氺), classified 85th in the Kangxi dictionary, which appears in characters like 泰 (great) and 求 (seek).

Characters with the water radical often relate to liquids or water-related meanings.

Examples include:

液 (liquid)

泉 (spring)

氷 (ice)

泳 (swim)

深 (deep)

江 (river)

河 (river)

湖 (lake)

海 (sea)

洋 (ocean)

泌 (secrete)

洐 (ditch flow)

淼 (vast water)

氹 (pond)

There are rare characters that use the full 水 shape as a radical, such as 沀 (ditch).