Colo. Rev. Stat. § 37-80-117
Whenever it is necessary for any duly authorized hydrographer from the office of the state engineer, or any hydrographer duly authorized by the state engineer or division engineer or water commissioner, or for any water official to make a rating of any weir or flume or measuring section of any canal, the owners, superintendent, or persons having charge and control of the diversion of water into said canal shall increase and decrease the flow of water into said canal as may be ordered and required by the person making such measurements in order that accurate ratings may be taken of the water flowing in said canal at different depths and gauge heights. Any person refusing so to regulate the flow of water into said canal for such purpose is guilty of a misdemeanor and, upon conviction thereof, shall be punished by a fine of not more than one hundred dollars for the first offense and not more than five hundred dollars for the second and succeeding offenses.
C.R.S. § 37-80-117