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DRAFT CONSOLIDATED HYDROLOGY REPORT PEAKING OPERATIONS OF FLAMING GORGE V I. STUDY OBJECTIVES tests of flow scenarios. The objective of this task is to have an hourly hydrology model which can be used to quantify the effects of peaking operations on the Green River below Flaming Gorge. The model, when calibrated, validated and documented, will be available for biologists and water resource planners to evaluate different operational scenarios for Flaming Gorge. The model will have the capability of doing in a few hours what, in the past, has been an intensive and costly process of conducting on-the-ground field II. INTRODUCTION During early scoping meetings for the Flaming Gorge Biological opinion, a need was identified for an hourly model to evaluate peaking power releases from Flaming Gorge Reservoir. Concurrently, the Bureau of Reclamation (Bureau) was adding a new reach to an existing hourly model of the Green River below Flaming Gorge. The Streamflow Synthesis And Reservoir Regulation (SSARR) model was being extended to Jensen, Utah. This model uses observed hydrographs at the upstream and downstream locations to calibrate three variables in a routing/attenuation algorithm. The variables are adjusted until the observed hydrographs are replicated. It is important in this calibration process that a wide range of flows and release patterns are tested in order to verify the model over the range of expected river conditions. The Bureau, in recent years, has been using SSARR to evaluate the effects of peaking operations on recreational rafting. Because most of the work in setting up an hourly model had been completed by the Bureau, a decision was made to use SSARR for the Section 7 peaking power analysis of Flaming Gorge Reservoir. Following the decision to use the SSARR model, a meeting was held with Jerold Lazenby and Randy Peterson of the Bureau's Upper Colorado River Regional office located in Salt Lake City, Utah. During that meeting, Mr. Peterson outlined the network structure he was using on the Green River below Flaming Gorge and went over how the SSARR model operates. Also discussed at the meeting were methods used to calibrate the model where gage information did not exist. The methodology entailed having a crew in the field for a two-day period when known releases were made from the reservoir. The crew would take hourly staff gage readings at each observation site, from which a flow vs stage relationship was developed.