The estimate shall include the following:
(a)
The expenses of bonding the assessment if authorized by law, other than an assessment to pay the costs and expenses necessary for the maintenance, repair, and operation of its existing works of reclamation and flood control.
(b)
The costs and expenses necessary for the completion, maintenance, and operation of any project adopted by the board prior to April 1, 1923.
(c)
The costs and expenses necessary for the adoption and carrying to completion of any project or work involved in or contained in the report of the California Debris Commission dated January 5, 1925.