Sections 11.20.030 through 11.20.080 are intended to provide for the extension of special public improvements into undeveloped areas of the city by encouraging the extension of such improvements and providing for the reimbursement of the costs of such improvements other than those costs which are for general public benefit by the owners of parcels which specifically benefit from such improvements and which are not subject to any other special assessments or special charges for the benefit which they receive from the special public improvement. (1976 Code § 18-4-2)