This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
溿 combines the water radical 氵 with 畔, which likely contributes both sound and the idea of a boundary or edge. The exact historical development is uncertain.
The water radical 氵 beside 畔 suggests a water's edge or shore, but the exact meaning is unclear.
For ハン, imagine a hand (ハン) reaching out from the water's edge: hand -> ハン, and the water radical 氵 marks the shore.