Notwithstanding any other provision of this code, the board of a district in which an improvement district exists may establish facilities use charges for the use of irrigation facilities in such improvement district and, in establishing such charges, may provide that water shall be furnished or delivered through such facilities only to lands in such improvement district in respect of which such facilities use charges or annual installments thereof, fixed as provided in this section, shall have been paid in advance. Such facilities use charges shall be in amounts equal to the respective amounts of the assessments theretofore levied against the lands in such improvement district for the purpose of providing such facilities. In establishing such charges the board of the district shall provide (a)that payment in full of any such assessment shall constitute payment in advance in full of such facilities use charge; (b)that all facilities use charges not so paid in advance in full shall be payable in annual installments, each such annual installment to be equal in amount to (i)the annual installment of the unpaid assessment theretofore levied against the land in respect of which such charge is payable and due on or before the next succeeding November 20th plus interest thereon at the rate provided in the order levying such assessment plus 10 percent in addition (added for anticipated delinquencies), plus (ii)all delinquent annual installments, if any, of such unpaid assessment together with penalties and interest at said rate on such delinquent installments; and (c)that payment of any annual installment of any such facilities use charge shall constitute payment in full of the annual installment of such unpaid assessment due on or before the next succeeding November 20th and of all delinquent annual installments, if any, of such unpaid assessment. Any proceedings heretofore taken by the board of any district to establish the facilities use charges authorized by this section are hereby confirmed, validated and declared legally effective.