In addition to the number of enterprise zones authorized by the provisions of section 135.210, the department of economic development shall designate one such zone in every county of the third class which has a population of less than twenty-five thousand inhabitants, and an assessed valuation of between two hundred and seventy million dollars and three hundred million dollars as published in the 1985 proceedings of the Missouri state tax commission. Such designation shall only be made if the area in the county which is to be included in the enterprise zone meets all the requirements of section 135.205.