Opinion ID: 1219144
Heading Depth: 3
Heading Rank: 2

Heading: Inclusion of Unconfined Aquifer in Definition of Natural Stream

Text: The trial court concluded as a matter of law that the unconfined aquifer is water of a natural stream, and that the proposed pumping of 200,000 acre feet per annum would deplete the flow of that stream as well as other natural streams in the San Luis Valley to a greater extent than allowable in order to satisfy the criteria in the definition of nontributary ground water in section 37-90-103(10.5). AWDI asserts first that the unconfined aquifer is not a natural stream within the meaning of section 37-90-103(10.5) because it does not fit the definition of natural stream in section 37-87-102(1)(b), 15 C.R.S. (1990). This argument has no merit. Section 37-87-102(1)(b) provides: As used in this article, unless the context otherwise requires: . . . . . (b) Natural stream means a place on the surface of the earth where water naturally flows regularly or intermittently with a perceptible current between observable banks, although the location of such banks may vary under different conditions. (Emphasis added.) The article referred to in the foregoing definition is Article 87, entitled Reservoirs. By its own terms, the definition does not apply to section 37-90-103(10.5), which appears in a separate article 90, captioned Underground Water. Also, section 37-90-103(10.5) specifically includes within the meaning of natural stream a natural stream as defined in sections 37-82-101(2) and 37-92-102(1)(b). The trial court found that the unconfined aquifer falls within these definitions as a stream system which arises as a natural surface stream which terminates within the state, together with its associated underflow and tributary water. AWDI also argues that the amount of surface stream depletion alone determines whether water is nontributary within the meaning of section 37-90-103(10.5). This is incorrect. That section specifically refers to sections 37-82-101(2) and 37-92-102(1)(b) as included within the definition of natural streams. Those sections in turn refer to a natural surface stream ... together with its underflow and tributary waters. Clearly then, the underflow and tributary waters of streams described in the natural stream legislation are included as part of the natural streams referred to in section 37-90-103(10.5), and the effect on such underflow and tributary waters must be considered in determining whether ground water to be withdrawn is nontributary. AWDI also challenges factual findings upon which the trial court relied in determining that the unconfined aquifer constitutes associated underflow and tributary water of a natural surface stream and therefore by definition is part of the natural surface stream. See §§ 37-82-101(2) and 37-92-102(1)(b). Specifically, AWDI contends that its evidence concerning the lack of hydraulic connection between the unconfined aquifer and surface streams was more weighty and credible than that of the objectors. Similarly, AWDI contends that its evidence concerning streambed conductance, which affects the movement of water into and out of the subsurface surrounding a stream is more persuasive. Our review of the record, however, reveals ample evidence supporting the trial court's findings on these matters. Issues of credibility are to be resolved by the trial court. Consequently, the findings will not be disturbed on appeal. See Upper Gunnison River, 838 P.2d at 847. [33] For the foregoing reasons we uphold the trial court's determination that the unconfined aquifer in the Closed Basin is part of a natural surface stream within the meaning of section 37-90-103(10.5).