; (F) a review of how the mitigation requirements for water resources development projects contributes to the resilience of water resources in the United States; (G) an assessment of whether mitigation is being done prior to or contemporaneously with the construction of projects, as required by section 906 of the Water Resources Development Act of 1986 ( 33 U.S.C. 2283 ); (H) an evaluation of compliance with section 906(d) of the Water Resources Development Act of 1986 ( 33 U.S.C. 2283(d) ) for the development of specific mitigation plans for projects, whether such plans were successful in mitigating the designated impacts of the projects, and, in instances where such plans were not successful, what actions the Secretary is taking to modify the plans such that they will be successful; and (I) an assessment of how the Secretary might take advantage of natural infrastructure in mitigation planning to reduce flood risks and flood recovery costs for some communities; and (2) submit to Congress a report that— (A) describes the results of the study conducted under paragraph (1); (B) includes recommendations to ensure compliance with and successful implementation of mitigation requirements for water resources development projects; and (C) includes recommendations to ensure existing programs and authorities include the use, to the maximum extent practicable, of natural infrastructure. 218. GAO study on application of Harbor Maintenance Trust Fund expenditures (a) Study Not later than 18 months after the date of enactment of this Act, the Comptroller General of the United States shall conduct a study of the operation and maintenance needs of federally authorized harbor and inland harbor projects, including— (1) an inventory of all federally authorized harbor and inland harbor projects; (2) an assessment of current uses of such projects (and, to the extent practicable, the national, regional, and local benefits of such uses), including the uses listed in section 210(d)(2)(B) of the Water Resources Development Act of 1986