D.C. Code § 10-110
The Mayor of the District of Columbia is authorized to close upper Water Street, between Twenty-second and Twenty-third Streets, Northwest, lying north of Potomac Park and south of square 62; provided, that the consent in writing of the owners of three-fourths of all private property on the south side of square 62 is first had and obtained; and upon the closing of said street between the limits named the Mayor of the District of Columbia is authorized to transfer the land contained in the bed of said street to the Director of the National Park Service, as part of the park system of the District of Columbia; provided further, that the said Mayor is authorized to enter upon said closed area at all times for the purpose of maintenance and repair of all existing sewers and sewer appurtenances.
D.C. Code § 10-110