Laserfiche WebLink
<br />.,", <br /> <br />. <br /> <br />MEMORANDUM <br /> <br />b <br /> <br /> <br />'Mr <br />L_ <br /> <br />Date: August 18, 1987 <br />To: Blaine Dwyer, CWRPDA <br />rrom: Chuek Brendecke, WBLA <br />Re: Treatment of Instream rlows in Gunnison Basin Study <br /> <br />"~1 <br /> <br />go <br />eo <br />N <br /> <br />This memorandum outlines the ways in which we propose to <br />flows in the development and operation of the upper Gunnison basin model. <br />memo is, hopefully, written in a form similar to that which will appear in <br />Memorandum No. 5 and the study report. <br /> <br />The <br />Task <br /> <br />INSTREAi'I rLOW REQUIREMENTS <br /> <br />There are several reaches of the Gunnison River and its tributaries for <br />which in stream flow regimes have been proposed or decreed, or for which there is <br />significant interest in flow enhancement. There is also concern over instream <br />flows for endangered species below the confluence of the Gunnison and the <br />Colorado River. These instream flow issues fall generally into four categories: <br />1) flows in the Black Canyon below the Gunnison Tunnel, 2) decrees and proposals <br />of the Colorado Water Conservation Board (CWCB), 3) privately held instream flow <br />rights, and 4) endangered species flow requirements at the state line. The way <br />in which each of these will addressed in the basin model is discussed below. <br /> <br />rlows in the Black Canvon <br /> <br />Proposed legislation to make the Black Canyon a National Park and to confer <br />Wild and Scenic status on the river through the Park would provide for instream <br />flows in the reach below the Gunnison Tunnel. Under the auspices of Congressman <br />Campbell's office and the CWCB, a technieal working group has been established <br />to develop criteria for these instream flows. This working group, which <br />includes fisheries, recreational, and other basin interests, has not yet defined <br />an instream flow regime for the reach. <br /> <br />Earlier studies (WBLA, 1986) suggest that certain instream flow regimes for <br />the Black Canyon could affect the potential for upper basin water development. <br />However, to wait for definition of the instream flow criteria by the working <br />group would require a significant delay of the basin study. In order to proceed <br />with the basin study it is necessary to assume a baseline instream flow regime <br />which can, if necessary, be modified later in a sensitivity analysis. <br /> <br />The baseline instream flow regime adopted was developed from preliminary <br />information prepared by the working group participants in April and May of 1987. <br />This information was reviewed to determine their desired quantities and timing <br />of instream flows. Based on this review, and on concurrent discussions with the <br />Teehnical Steering Committee, it was ~~Ci~ that a year around minimum flow of <br />300 cfs would adequately support fishe'I"ie. nd was inStituti~...l.lY.: aChievabl.e. <br /> <br />~ ~ ~ D WJ ~ ,~!if'i;tlk:... r\. <br />..~~&IYf:fUI <br />AUG 2 f 1987 <br /> <br />COLORADO W(T'- <br />C'r."!~f::"?VATrn~ ,','-',..... \ <br /> <br />AU~ 1 ~ '~~1 <br /> <br />~oWat<w~ <br />~~""'"'~~.lt~.~'U.!. <br /> <br />WBLA Inc. 1909 Broadway, #3 Boulder, Colorado 80302 <br />