7415 - Laserfiche WebLink

Home Browse Search

,Tia Juana Bottom Calibration work on the last section of the model from Ouray Refuge to Tia Juana Bottom began in June of 1988, after the completion of the collection of data to build a rating table. The time period selected for the calibration was July and August 1987. This period was selected because it represents a time when a series of controlled releases were being made from Flaming Gorge. Starting on July 6, 1987, a beginning release of 2100 cfs was established. This release was held constant, allowing flows at Jensen, Utah to stabilize and only vary 100-200 cfs depending upon the flow of the Yampa River. In successive weeks, releases from the dam were decreased to 1800 cfs, 1500 cfs, 1300 cfs, 1,000 cfs, and 800 cfs. In mid-August, peaking power releases were resumed and a release pattern of 1200 cfs to 2600 cfs was established. During this period, numerous biological sampling and backwater mapping research projects were in progress all along the Green River, from the dam down to Willow Creek. Each of these studies needed to be correlated to flow information at a specific time and location; unfortunately, the only information available was the Jensen USGS gage. Based upon request for flow information at other locations, SSARR was set up and calibrated for the test release period. The set up of SSARR down to Tia Juana Bottom was accomplished by requesting release information from Flaming Gorge. This information was provided by the Western Area Power Administration, who provided hourly power production at Flaming Gorge in megawatts. The megawatts information was converted to cfs by multiplying megawatts by 32. This conversion factor was supplied by the Bureau and is based upon various rating and head factors unique to the Flaming Gorge dam and powerplant. Next, hourly flow information at Deerlodge Park on the Yampa, Jensen on the Green River, Randlett on the Duchesne River, and Watson on the White River was requested from the USGS. This information was then keypunched and reformatted for SSARR model input. The final step was the set up of the SSARR model network and building the input data file. The extended network included computational nodes at the Green- Duchesne confluence, the Green-White confluence, and Tia Juana Bottom. Nodes were later added to represent gaged locations on the Duchesne and White Rivers. These reaches were found to be necessary to accurately control the time at which water arrived at Tia Juana Bottom. Without these reaches water arrived instantaneously and precluded any accurate calibration. Calibration of the model was accomplished using the following data recorded July 1, 1988 through August 31, 1988: Flaming Gorge releases, flow of the Yampa, recorded flow at Jensen, Duchesne and White River flows and recorded flow at Tia Juana Bottom. 14