When a departmental proceeding that is conducted pursuant to sections 46-229 to 46-229.04 concerns the partial cancellation of an appropriation, the department may receive evidence on the question of whether, following such partial cancellation, a reduction in the rate of diversion to the maximum rate prescribed in section 46-231 would result in an authorized diversion rate less than the rate necessary, in the interests of good husbandry, for the production of crops on the lands that remain subject to the appropriation. If the director determines, based on a preponderance of the evidence, that such rate would be less than the rate necessary, in the interests of good husbandry, for the production of crops, he or she may approve a diversion rate for the remaining portion of the appropriation greater than the maximum rate authorized by section 46-231. Such increased rate can be no greater than the rate authorized for the appropriation prior to the partial cancellation and no greater than the rate determined by the director to be necessary, in the interests of good husbandry, for the production of crops on the lands that remain subject to the appropriation.