Klamath Infrastructure Improvement Act This bill amends the Klamath Basin Water Supply Enhancement Act of 2000 to authorize the Department of the Interior to carry out activities, including entering into contracts or making financial assistance available, to: (1) plan, implement, and administer programs to align water supplies and demand for irrigation water users associated with the Klamath Project (Bureau of Reclamation project in California and Oregon), with a primary emphasis on programs developed or endorsed by local entities comprised of representatives of those water users; (2) plan and implement activities and projects that avoid or mitigate environmental effects of irrigation activities or that restore habitats in the Klamath Basin watershed; and (3) limit the net delivered cost of power for covered power uses. "Covered power use" means a use of power to develop or manage water from any source for irrigation, wildlife purposes, or drainage on land that is: (1) associated with the Klamath Project; or (2) irrigated by the class of users covered by the agreement dated April 30, 1956, between the California Oregon Power Company and Klamath Basin Water Users Protective Association and within the Off Project Area. Interior must submit a report to Congress that identifies the power cost benchmark (the average net delivered cost of power for irrigation and drainage at reclamation projects in the area surrounding the Klamath Project that are similarly situated to the project). The replacement of the C Canal flume within the Klamath Project shall be considered to be, and shall receive the treatment authorized for, qualified emergency extraordinary operation and maintenance work in accordance with federal reclamation law.