Where the proposed residential development is in close proximity to an already existing neighborhood park, as determined by the city council, through the general plan, and if the already existing park is outside of the proposed limits of the development, the developer will be required to make a cash payment, in lieu of dedication, equivalent to the cost of the park land as determined by the city council based on the adopted ratio of park land per dwelling unit. These moneys will be used only in the acquisition and development of that community park serving that proposed development. Cash payment shall be made to the city at the time of filing the tentative tract map, the final tract map or prior to issuance of a building permit, whichever event first occurs, and shall be deposited with the city treasurer in a park development fund to be used solely for acquisition and development of park facilities.