If the council determines to grant said petition or any part thereof, the council may provide in the vacation ordinance that said ordinance shall not become effective until the owners of property abutting upon the street or alley, or part thereof so vacated, and in whom the title to said vacated street or alley shall vest, shall pay to the city one-half the appraised value of the area so vacated and vesting in said abutting owner. The appraised value shall be determined upon the basis of an appraisal performed at the expense of the petitioner or petitioners and by an appraiser approved by the city. If the vacation ordinance requires payment as specified in this section, said payment totaling one-half the appraised value of the area so vacated shall be made to the city within ninety days after passage of the ordinance by the city or said ordinance shall become void. (Ord. 632 §1 (part), 1981).