(a) Any person who has a valid water right pursuant to Section 1226.1, who files a claim of water right with the board on or before December 31, 1977, has a water right priority as of the date of the construction of the dam or other water impoundment structure.
(b) Any person who has a valid water right pursuant to Section 1226.1, who files a claim of water right with the board after December 31, 1977, and before January 1, 1998, has a water right priority as of the date of filing.