Upon organization of such subdistrict, the board of directors of said district, acting as the board of directors of said subdistrict, are authorized and required to prepare and adopt as the official plans for said subdistrict a comprehensive detailed plan showing the nature of the improvements or works, including all canals, reservoirs, and ditches, whether within or without the district, and the estimated cost of each principal part of said system or works.
C.R.S. § 37-46-115