Laserfiche WebLink
<br />1/ ~ ~-\- r(-:J~Ft,}>t~~ <br /> <br />00016Z <br /> <br />,. Table 3. Minimum and optimum flow recommendations for IFIM/PHABSIM study <br /> streams by time period, species, and life stage (concluded). <br /> Critical Minimum Optimum <br /> Species Life stage Time period Flow Flow <br /> Rainbow . Spawning 04/0l-05115 lOO 150. <br /> Rainbow Incubation 04/0l-06/0l lOO 150 <br /> Rainbow Hatching 06/0l-07/0l lOO l50 <br /> Rainbow Fry 06/l5-07/15 50 50 <br /> Rainbow Juvenile. 07/l5-l0/l5 50 l50 <br /> Rainbow Adult l2 months lOO 225 <br /> Taylor River <br /> Brown Spawning lO/l5-ll/l5 50 lOO <br /> Brown Incubation 1l/Ol-05/0l 50 lOO <br /> Brown Hatching 04/0l-06/0l 50 100 <br /> Brown Fry 05/l5-07/0l 50 50 <br /> Brown Juvenile 07/0l-10/l5 50 200. <br /> Brown Adult l2 months 50 250 <br /> <br />Arkansas River <br /> <br />Minimum flows for all brown trout life stages in the Arkansas River <br />(Table 3) within the study section is 200 cfs and the optimum is 400 cfs. <br />The only time (in the past iO years) that the minimum flow (at the <br />Wellsville gage (within the study area) was less than 200 cfs was in 1977, <br />the near record low water year. The 400 cfs optimum flow is met or exceeded <br />the majority of the t'ime.Therefore, both the minimum and optimum flow <br />recommendation for the Arkansas River (Table 3) should be targets the water <br />management agencies should be able to maintain almost all of, the time. The <br />data in Table 1 indicates the brown trout in the Arkansas River (on May <br />25th) are the largest fry (on average) of any group from any study stream in <br />any year. They also had the widest range in size of any stream (in <br />late-May) which indicates their hatching and emergence in the Arkansas River <br />is spread over perhaps a 2-month period, i.e., April-May. <br /> <br />Blue River <br /> <br />Minimum and optimum flow recommendations for both rainbow and brown <br />trout in the Blue River are 50 cfs and 100 cfs, respectively, for all life <br />stages (Table 3). According tp flow records for the Blue River below Dillon <br />Dam, the minimum flow recommendation of 50 cfs has been violated in 12 years <br />since 1965 and lO times in the past lO years. Flow reductions below 20 cfs <br />for a week or more during the critical winter-early spring brown egg <br />incubation and hatching period have been commonplace occurrences since <br />1977. Since the Denver Water Department (Dwn) operates Dillon Dam, these <br />dramatic flow reductions clearly indicate the cavalier attitude of the Dwn <br />towards the needs of aquatic wildlife and other recreation uses and users of <br /> <br />s~, ~i C. ::-f ~.'- <br /> <br />..'j', <br /> <br />Ii 00002389 <br />