changes in construction cost indices since May 1, 2011, that are applicable to the types of construction involved in the activities described in that paragraph. (e) Fort Belknap Indian Community Domestic Water Supply and Wastewater Systems Account (1) Mandatory appropriations Out of any funds in the Treasury not otherwise appropriated, the Secretary of the Treasury shall deposit in the Fort Belknap Indian Community Domestic Water Supply and Wastewater Systems Account established under paragraph (4) of section 11(c) $69,036,800, as adjusted to reflect changes in construction cost indices since May 1, 2011, that are applicable to the types of construction involved in the activities described in that paragraph. (2) Authorization of appropriations In addition to the amounts made available under paragraph (1), there is authorized to be appropriated for deposit in the Fort Belknap Indian Community Domestic Water Supply and Wastewater Systems Account established under paragraph (4) of section 11(c) $54,243,200, as adjusted to reflect changes in construction cost indices since May 1, 2011, that are applicable to the types of construction involved in the activities described in that paragraph. (f) Milk River Project mitigation (1) In general As soon as practicable after the date on which amounts are appropriated under paragraph (2), the Secretary shall make a grant to the State in the amount of $21,000,000, to be used by the State only to support the cost of construction involved in the mitigation activities that will be implemented for the Milk River Project, including by making grants under section 8(c)(1). (2) Authorization of appropriations There is authorized to be appropriated to the Secretary to carry out this subsection $21,000,000 for fiscal year 2021, as adjusted to reflect changes in construction cost indices since May 1, 2011, that are applicable to the types of construction involved in the mitigation activities that will be implemented for the Milk River Project. (g) Federal contribution to the Milk River