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<br />IG~G <br /> <br />In developing fish and wildlife plans for the proposed reservoir, the <br />State Division of Wildlife indicated a desire to establish a coldwater <br />tailwater fishery downstream from the dam. The proposal was for a <br />put-grow-and-take fishery. The reservoir release temperatures have <br />been evaluated against the average weekly maximum (AWM) temperature <br />for the survival of acclimated rainbow trout, which exhibit the greatest <br />tolerance to high temperatures of the various trout species and would <br />be the most likely one to be planted in the tailwater area. As was <br />indicated above, the temperature of the bottom waters, and thus of the <br />releases, was in excess of 2Do C for 60 days. Since the AWM for rainbow <br />trout is about 18.30 C, all trout in the tailwater fishery would be <br />expected to be lost. During the 1967 simulation, the maximum release <br />temperature was 18.30 C, i.e. right at the AWM for rainbow trout. Under <br />these conditions, some loss during the summer would be expected, with <br />hardier individuals surviving, at least in the stream reach immediately <br />below the dam. The maximum release temperature for 1963 was 17.70 C <br />and over summer survival could be expected for some little distance <br />downstream from the dam. These conditions are not inconsistent with <br />the management of a put-and-take fishery. <br /> <br />Biological Studies <br /> <br />Water samples were collected in both August and October at two stations <br />in the South Platte River. The upstream station was located near <br />Masters as in the bacteriological study. Specifically the samples <br />were taken at the headgate to the Jackson Lake Inlet Canal. Diversions <br />to the,lake were being made at the time of sampling. The downstream <br />station was located at the diversion dam to the Ft. Morgan Canal. <br />These samples were analyzed for total dissolved solids, standard cations <br />and anions, and dissolved nutrients, i.e. nitrate-nitrite and ortho- <br />phosphate. Algal growth potential (AGP) assays were also run on these <br />water samples. <br /> <br />. <br /> <br />Nutrient levels in the raw river water were relatively high, with the <br />Masters sample exhibiting the greater concentration of both inorganic <br />nitrogen and orthophosphate. The AGP also affirmed the high nutrient <br />content of the water with 21-day cell counts of 135,500 and 83,200 <br />cells per cubic meter for the Masters and Ft. Morgan stations respec- <br />tively from the August samples. However, the 21-day biomass for these <br />samples were 57.3 and 201.4 grams per cubic meter dry weight for the <br />upstream and downstream stations respectively. The October samples <br />exhibited even greater growth at the Masters site with a 21-day count <br />over a million cells per cubic meter. Concurrently, the Ft. Morgan <br />station only produced 40,400 cells per cubic meter. <br /> <br />21 <br />