levee, embankment, hill, slope
陂 centers on a raised or sloping earthwork: a levee or embankment, and by extension a hill or slope. All meanings share the idea of an inclined or piled-up landform.
陂 combines ⻖ (mound, hill) with 皮, which likely contributes the sound. The character originally referred to a sloping bank or dike.
The left side ⻖ is a mound or hill, and the right side 皮 suggests a covering or skin. Picture a levee as a skin of earth draped over a slope to hold back water.
For ヒ, imagine a levee made of heaped earth: the word 'heap' sounds like ヒ, and the piled-up soil forms the embankment.