7415 - Laserfiche WebLink

Home Browse Search

The third recorder was not installed until late July 1987 because permission was not obtained from the Ute Indians until the spring runoff had begun. The recorder was installed at the site of a former USGS gage which was discontinued in the 1960's. This recorder has been operating successfully since its installation and has only two gaps in the record. One gap was caused from our testing a weatherization technique, and the other occurred because of a clock malfunction. The weatherization technique being tested consisted of placing styrofoam peanuts in the stilling well to prevent freezing. This technique failed completely as the float became jammed and data was lost for several weeks. This problem occurred at all three recorders during mid-November 1987. The amount of styrofoam was reduced in early November and the gages functioned through the winter. Concurrent with the installation and operation of the recorders, Service staff took width, depth and velocity measurements at each of the recorder sites. These measurements were then used to develop stage vs flow relationships for each of the recorder sites. During 1987, two measurements were taken at Mitten Park and Ouray Refuge, and one measurement was taken at Tia Juana Bottom. Flows measured at Mitten Park were 1,424 cfs and 2,416 cfs. Flows Measured at Ouray refuge were 2,039 and 4,398 cfs. The single flow measured at Tia Juana Bottom was 2,160 cfs. Based upon these measurements, rating tables were developed for Mitten Park and the Ouray Refuge. The rating table relationships were first developed graphically by plotting the flow vs stage and a equation for the line derived. The rating table was then developed by plugging the equation into Lotus and incrementing the stage. A rating table for Tia Juana Bottom could not be developed based upon one measurement. During January of 1988, discussions were held with the Bureau and a target flow of 6,000 cfs was established for the upper measurement at the Mitten Park and Ouray Refuge sites. This target was used to represent the usual summer condition when Flaming Gorge is peaking between 1,200 cfs and 4,200 cfs, and the Yampa is contributing up to 2,000 cfs. This would produce rating tables which were considerably more accurate at lower flows than those produced with higher flows out of the range that are to be considered in the study. During the 1988 spring runoff period, an effort was made to get additional measurements at the three recorders when the flow at Jensen was in the 6,000 cfs range. Flows of 7,639 cfs, 6,442 cfs, and 7,673 cfs were measured at Mitten Park, Ouray, and Tia Juana Bottom respectively. The flow at the Mitten Park site was a little higher than planned, but was the best that could be obtained with unpredictable weather conditions. 5