Where a park, recreational facility or open space has been designated in the City of Marina park and recreation plan or in an element of the city general plan, and it is to be located in whole or in part within a proposed subdivision of more than fifty parcels or in the vicinity of a multiple-family dwelling project of five or more units so as to serve the immediate and future needs of the residents of the subdivision or multiple-family dwelling project, the owner or developer shall dedicate land for a city park sufficient in size and topography to serve the residents of the subdivision or multiple-family dwelling project. The amount of land to be dedicated shall be determined to the following standards and formula: