; and (2) is or was held on or after June 24, 2009, at the United States Naval Station, Guantanamo Bay, Cuba, by the Department of Defense. 539. (a) The Secretary of Homeland Security (in this section referred to as the Secretary ) shall, on a bimonthly basis beginning immediately after the date of enactment of this Act, develop estimates of the number of migrants anticipated to arrive at the southwest border of the United States. (b) The Secretary shall ensure that, at a minimum, the estimates developed pursuant to subsection (a)— (1) cover the current fiscal year and the following fiscal year; (2) include a breakout by demographics, to include single adults, family units, and unaccompanied children; (3) undergo an independent validation and verification review; (4) are used to inform policy planning and budgeting processes within the Department of Homeland Security; and (5) are included in the budget materials submitted to Congress in support of the President’s annual budget request pursuant to section 1105 of title 31, United States Code, for each fiscal year beginning after the date of enactment of this Act and, for such budget materials shall include— (A) the most recent bimonthly estimates developed pursuant to subsection (a); (B) a description and quantification of the estimates used to justify funding requests for Department programs related to border security, immigration enforcement, and immigration services; (C) a description and quantification of the anticipated workload and requirements resulting from such estimates