; and (B) to pay the costs of operation and maintenance of a project of the non-Federal interest for which a non-Federal cost-share is required. 1005. Non-Federal sponsor reimbursements (a) Definition of unreimbursed funds In this section, the term unreimbursed funds , with respect to a project carried out by the Secretary, means funds spent by a non-Federal sponsor for the project that have not been reimbursed by the Secretary under an existing agreement before the end of the fiscal year following the fiscal year in which the funds were spent. (b) Application of unreimbursed funds In the case of a project carried out by the Secretary under an existing agreement for which the non-Federal sponsor has unreimbursed funds, on the request of the non-Federal sponsor, the Secretary shall— (1) credit the unreimbursed funds to the non-Federal cost-share requirement of that non-Federal sponsor for another project to be carried out by the Secretary; or (2) reimburse the funds to the non-Federal sponsor. 1006. Challenge cost-sharing program for the management of recreation facilities Section 225(c) of the Water Resources Development Act of 1992 ( 33 U.S.C. 2328(c) ) is amended— (1) by striking non-Federal public entity each place it appears and inserting non-Federal public or private entity ; and (2) by adding at the end the following: (4) Treatment In carrying out this subsection, the Secretary shall ensure that a private entity is subject to the same regulations and requirements as a non-Federal public entity. . 1007. Cost estimates Section 2008(c) of the Water Resources Development Act of 2007 ( 33 U.S.C. 2340(c) ) is amended by striking before, on, or after and inserting on or after . 1008. Retroactive changes to cost-sharing agreements Study costs incurred before the date of execution of a feasibility cost-sharing agreement for a project to be carried out under section 206 of the Water Resources Development Act of 1996 ( 33 U.S.C. 2330 ) shall be Federal costs, if— (1) the study was initiated before October 1, 2006