Description: Water Service Area: Imperial Irrigation District water service area determined by the Secretary of the Interior as the All-American Canal service area boundaries within Imperial County, as stipulated under the 1932 Boulder Canyon Act Contract and further recognized is said agreement as “Boundary of Additional Areas in Proposed Enlarged Imperial Irrigation District” for future inclusion.Water Service Unit: The district boundaries are comprised of three units, the Imperial Unit as established in 1931, including any subsequent modifications which is the primary area of water delivery, followed by less developed areas consisting of the West Mesa Unit, the East Mesa Unit and Pilot Knob which are located immediately to the west, east and far east, respectively, in relation to the Imperial Unit. Additional lands may be “included” to any unit as approved by the board.