; (iv) donations of land, building, or building materials; (v) in-kind construction, technical, and planning services; and (vi) any combination of funds described in this subparagraph. (d) Transfer At the discretion of an eligible local government receiving a rehabilitation and construction grant under subsection (a)(1) or an innovation and recreation program grant under subsection (a)(2), and if consistent with the approved application for such grant, the a grant may be transferred in whole or in part to private nonprofit agencies, provided that assisted recreational areas and facilities owned or managed by such private nonprofit agencies offer recreation opportunities to the general population within the jurisdictional boundaries of the local government. (e) Payments Grant payments may be made only for rehabilitation and construction or innovation and recreation projects and programs approved by the Secretary. In the case of rehabilitation and construction and innovation projects, such payments may be made periodically consistent with the rate of progress toward the satisfactory completion of a project, except that the Secretary may, when appropriate, make advance payments on approved rehabilitation and construction and innovation projects in an amount not to exceed 20 percent of the total project cost. (f) Modification of project The Secretary may authorize modification of an approved rehabilitation and construction or innovation project only when a grantee has adequately demonstrated that such modification is necessary because of circumstances not foreseeable at the time such project was proposed. 104. Requirements for rehabilitation and construction grants (a) Priority criteria The Secretary shall establish priority criteria for the selection and approval of projects to be funded by a rehabilitation and construction grant made pursuant to section 103(a)(1), which shall include whether and the extent to which the project would— (1) serve a community with a high population density