sprinkle, lively, vigorous
溌 centers on energetic outward movement: sprinkling liquid, or a lively, vigorous spirit that bursts out.
溌 is the modern simplified form of 潑. The older form combines 氵 (water) with 發, which likely contributed the sound and the idea of sending out or emitting. The modern 発 component is a simplification of 發.
Water 氵 combined with 発 (depart, emit) suggests water being sent out: sprinkling. The same outward energy gives the sense of liveliness and vigor.
For ハツ, imagine a lively hat that sprinkles water everywhere: hat -> ハツ, and the hat's energy makes the scene vigorous.