COSA Irrigation Ditch Reclamation/Restoration

Hello COSA Members,

Does anyone have experience with the obligations or legalities surrounding irrigation ditch reclamation/restoration?
Specifically, when an irrigator/provider moves to pipe their water supply and abandon their existing open ditch, are they under any obligation to "fill the hole" as it were?

In short, the provider is piping the water in a new alignment (not the existing open ditch alignment) and has no plans to restore the old ditch.
I’d appreciate any expertise or experiences you’d be willing to share.

Thank you,
Andy Cole
Cole Conservation Consulting LLC