D.C. Code § 39-117

(a) There is established as a special fund the DCPL Revenue-Generating Activities Fund (“Fund”), which shall be administered by the Board in accordance with subsection (c) of this section.
(b) The Fund shall consist of the revenue from revenue-generating activities and services described in §§ 39-105(a)(14) , (16) , and (17)(A)(ii)-(iii) and 39-107 .
(c) The Fund shall be used for the following purposes:
(1) Payment of any expenses associated with activities and services described in §  39-105(a)(14) , including expenses for space rental and special events associated with the activities and services authorized in §  39-105(a)(14) ;
(2) Payment of any non-personnel costs related to the library services mission of the District of Columbia Public Library;
(3) To support the operations of the District of Columbia Public Library, including programming and facilities improvements, and to purchase food, snacks, and non-alcoholic beverages for the general public, District of Columbia Public Library program participants, and District government employees; and
(4) Payment of the costs of temporary and when-actually-employed employees whose work is intended to generate revenue from the activities described in §§39-105(a)(14) , (16) , and (17)(A)(ii) and (iii) and 39-107 .
(d) (1) The money deposited into the Fund but not expended in a fiscal year shall not revert to the unassigned fund balance of the General Fund of the District of Columbia at the end of a fiscal year, or at any other time.
(2) Subject to authorization in an approved budget and financial plan, any funds appropriated in the Fund shall be continually available without regard to fiscal year limitation.