When any drainage district organized under the provisions of sections 31-301 to 31-305 or 31-401 to 31-408 is comprised of territory solely within one county and is inactive for a period of at least five years, as determined by resolution of the county board, the county board may order the district dissolved. The county board shall file copies of such order of dissolution with the county clerk and the county treasurer. Upon receipt of such order, the county treasurer shall transfer any remaining funds of the dissolved drainage district to the general fund of the county.