The Official Map shall be deemed conclusive with respect to the location and width of streets and public drainageways and the location and extent of flood control basins and public areas, whether or not such streets, ways, basins or areas are improved or unimproved or are in actual physical existence. Upon receiving an application for development, the Township may reserve for future public use the aforesaid streets, ways, basins and areas shown on the plat or site plan for a period of one year after the approval of the final plat or site plan or within such further time as may be agreed to by the developer. Unless during such period or extension the Township shall have entered into a contract to purchase or institute condemnation proceedings according to law for the fee or a lesser interest in the land comprising such streets, ways, basins or areas, the developer shall not be bound by such reservations shown on the plat and may proceed to use such land for private use in accordance with applicable development regulations. The provisions of this section shall not apply to streets and roads, flood control basins or public drainageways necessitated by the subdivision or land development and required for final approval.