Such plans and specifications shall show not merely the location, width, and depth of the ditches, but also the work to be done in removing obstructions from water courses, the building of pumping stations, dams, flumes, floodgates, fences to protect the district, and such levees as may be necessary to protect the land from overflow. Whenever federal financial or other assistance is furnished in connection with the planning or construction of the proposed improvements, such plans and specifications shall be detailed only to the extent required by the federal department or agency responsible for furnishing such assistance.