Section 37-84-117 - Reservoirs in streams(1) The owners of any reservoir located upon or in the bed of any natural stream or through which any natural stream flows, for the purpose of storing or diverting water, at the expense of the owner, shall furnish a complete survey of the contour lines of the reservoir for the state engineer's approval. Alternatively, in the discretion of the state engineer, a survey of the contour lines of the reservoir shall be made under the supervision of the state engineer, the deputy state engineer, or the division engineer of the division in which the reservoir is located. Contour lines must be ascertained for at least every vertical foot in depth and, where deemed necessary by the state engineer, for fractions of a foot. The owners of any reservoir shall prepare a table to be filed with and approved by the state engineer, showing the capacity, in cubic feet, for each foot in depth or fraction of a foot in depth of the reservoir. The owners of the reservoir shall file a copy of the table with the division engineer in whose division the reservoir is located. All maps, plats, field notes, tables, and surveys for a reservoir shall be filed with and approved by the state engineer and remain a part of the records of the state engineer's office.(2) The owners of a reservoir described in subsection (1) of this section, at their own expense, under the supervision and with the approval of the state engineer, shall permanently fix and maintain a gauge rod or other instrument, or both, as directed by the state engineer, to measure the surface elevation of the reservoir at or near the outlet of the reservoir, marked in feet and tenths and one-hundredths of a foot, and in correspondence with the contour lines, from and by means of which the amount of water stored in the reservoir may be correctly ascertained. The owners, at their own expense, and under the supervision and with the approval of the state engineer, shall construct and permanently maintain a suitable and permanent measuring structure equipped with self-registering devices, according to plans and specifications approved by the state engineer, either in the bed and channel of every natural stream or watercourse discharging waters into the reservoir or on each release from the reservoir by means of which, in combination with the amount of water stored, all of the water flowing into the reservoir from the natural stream or watercourse may be definitively ascertained and determined at all times.(3)(a) Any instruments or structures described in subsection (2) of this section are subject to inspection at all times by the owner or duly authorized agent or representative of the owners of any appropriation of water from the stream upon or in which the reservoir is constructed or operated.(b) The state engineer or division engineer may refuse to allow any water to be taken into or diverted from a reservoir if: (I) The owners of the reservoir fail to construct or permanently maintain any required instruments or structures, equipped as described in subsection (2) of this section; or(II) Except as specified in subsection (3)(c) of this section, within thirty-five days after the state engineer or division engineer has provided written notice to the owners or their agents or employees directing the owners to make a contour survey, as described in subsection (1) of this section, the owners fail to cause a complete survey of the contour lines of the reservoir to be made.(c) If suitable instruments and structures have been installed and equipped and the owners, their agents, or their employees are making good-faith efforts to complete the contour survey, the state engineer and division engineer may allow water to be stored in any such reservoir after the expiration of the thirty-five days notice as described in subsection (3)(b)(II) of this section.(4) If the state engineer or a division engineer receives from the owner of a water right appropriating water from a stream upon which a reservoir is located, or a stream that is tributary to such a stream, a complaint alleging facts against the owner of the reservoir that, if true, would amount to a violation of this section, the state engineer or division engineer shall investigate the complaint and, if the allegations are found to be true, shall enforce this section.(5) The state engineer may order that an owner of a reservoir release an amount of water from the reservoir that, in the determination of the state engineer, is necessary to prevent evaporation on the surface of the reservoir from depleting the natural flow of the stream running through the reservoir that would otherwise be available for use by other appropriators. In determining the quantity of any evaporation release under this section, the state engineer shall compute the surface evaporation from the reservoir and deduct from the surface evaporation any accretions to the streamflow resulting from the existence of the reservoir and any natural depletions to the streamflow that would have resulted if the reservoir were not in existence.Amended by 2017 Ch. 47, § 12, eff. 8/9/2017.L. 01: p. 195, § 6. R.S. 08: § 3253. L. 11: p. 466, § 6. C.L. § 1732. CSA: C. 90, § 130. CRS 53: § 147-7-18. C.R.S. 1963: § 148-7-17. L. 65: p. 1241, § 1. L. 69: p. 1222, § 13. L. 2017: Entire section amended, (SB 17-026), ch. 47, p. 145, § 12, effective August 9.