Following the creation of a service district as provided in section 11-28.1-01, the board of county park commissioners shall prepare plans and specifications for such project, including an estimate of the probable cost. The plans, specifications, and estimates provided for shall be approved by a resolution of the board of county park commissioners. The plans, specifications, and estimates shall be the property of the county and shall be filed in the office of the county auditor and shall remain on file in the auditor’s office subject to inspection by interested persons.