existing structures on the Robert F. Kennedy Memorial Stadium Campus. (3) Timing of payments Not later than 30 days after the date of the conveyance under subsection (a), the District of Columbia shall pay to the Secretary an amount equal to one-fourth of the amount of the consideration determined under this subsection, and shall pay the remaining balance in equal amounts on the first day of each of the next 3 fiscal years which begin after the expiration of the 1-year period which begins on the date on which the District makes the initial payment under this paragraph. (c) Terms and conditions (1) Certification regarding development of property As a condition of the conveyance under subsection (a), the District of Columbia shall certify to the Secretary of the Interior prior to the conveyance that the development or use of any property conveyed under such subsection shall meet the following requirements: (A) The development or use shall not undermine the restoration of the wetlands south of Kingman Island. (B) The development or use shall provide for improved public access to the Anacostia River including through walking trails and kayak and canoe areas that complement the Anacostia River Trail, and shall not interrupt the design of the Anacostia River Trail. (2) Additional terms and conditions The Secretary may require such additional terms and conditions in connection with the conveyance under subsection (a) as the Secretary considers appropriate to protect the interests of the United States. (d) Payment of costs of conveyance (1) Payment required The Secretary of the Interior shall require the District of Columbia to cover the costs to be incurred by the Secretary, or to reimburse the Secretary for such costs incurred by the Secretary, to carry out the conveyance under subsection (a), including survey costs, costs for environmental documentation, and any other administrative costs related to the conveyance. If amounts are collected from the District of Columbia in advance of the Secretary incurring the actual