Any district organized pursuant to RCW 85.05.610 or pursuant to any other provisions of chapter 85.05 RCW as now or hereafter amended may include any Indian trust lands and restricted lands whenever the congress of the United States (1) authorizes the inclusion of such lands in such district and (2) provides authority for such district to assess and to tax such lands for necessary expenses in the maintenance, operations and capital improvements on such diking and drainage system.