; and (2) for which the Secretary determines the flowage easement or portion of the flowage easement is not required to address backwater effects. (b) No liability The United States shall not be liable for any damages to property or injuries to persons from flooding that may be attributable to the operation and maintenance of Rough River Dam, Kentucky, on land that was encumbered by a flowage easement extinguished under subsection (a). (c) Authorization of appropriations There is authorized to be appropriated to carry out this section $10,000,000, to remain available until expended. 1098. Small flood control projects Subsection (a)(1) of section 205 of the Flood Control Act of 1948 ( 33 U.S.C. 701s ) (as amended by section 1017(b)(6)) is amended by inserting and projects that use natural features or nature-based features (as those terms are defined in section 1184(a) of the Water Infrastructure Improvements for the Nation Act ( 33 U.S.C. 2289a(a) ) after nonstructural projects . 1099. Comprehensive study of Mississippi River System from Old River Control Structure to Gulf of Mexico (a) Development The Secretary, in collaboration with the heads of other relevant Federal agencies, shall conduct, and submit to Congress a comprehensive study of the lower Mississippi River, and the tributaries and distributaries of the Mississippi River, from the Old River Control Structure near Point Breeze, Louisiana, to the Gulf of Mexico, including an examination of— (1) hurricane and storm damage reduction, flood risk management, structural and nonstructural flood control, and floodplain management strategies, including the consideration of natural features or nature-based features (as those terms are defined in section 1184(a) of the Water Infrastructure Improvements for the Nation Act ( 33 U.S.C. 2289a(a) )); (2) structural and operational modifications to completed water resources development projects within the study area