Matthew Poole and continuators on Genesis 26:18

18 And Isaac digged again the wells of water which they had digged in the days of Abraham his father : for the Philistines had stopped them, after the death of Abraham: and he called their names after the names by which his father had called them.

For though there might be a brook there, probably it was but little and soon dried up.

He digged those rather than new ones, partly to keep up his Fathers memory, and partly because he had most right to them, and others less cause of quarrel with him about them.