The hearing shall be held before the board and a quorum shall be present. The hearing may be adjourned from time to time by the president. All evidence relevant to the engineering survey and report, the recommendation that a replenishment assessment pursuant to this chapter be levied, and the determination of the area benefited by such assessment and replenishment program, may be introduced. Upon completion of the hearing, the board shall, by resolution, make specific findings on all facts relevant and material to the purposes for which a replenishment assessment, if any, may be levied under this chapter. In the event the district establishes a replenishment program and levies assessments hereunder, and such program is continued in subsequent years without substantial change and at the same rate of assessment, the board may dispense with the notice, hearing, and findings required by Section 31631.5 and this section.