A map must accompany the application showing source of supply, point of diversion, tie to a legal land corner, and general plan of the proposed development. If for irrigation, it must clearly show the lands to be irrigated. For small projects, maps or sketches prepared by the applicant on forms provided by this office will be acceptable if legible and accurate. For larger projects, maps on any reasonable scale prepared by engineers in planning the project may be required. (Supplemental to RCW 90.03.260.)