The legislature declares that courthouses, jails, bridges, hospitals, public libraries, facilities for the holding of county fairs, cultural facilities, juvenile detention homes, athletic facilities, parking structures, administrative facilities, facilities for housing equipment, repairing equipment and servicing equipment and sewerage facilities are necessary public buildings, and the purchase of books or other library resources, construction or repair of public roads, construction and acquisition of water, sewer or sanitary landfill systems and airports are necessary public projects.