Laserfiche WebLink
<br />. <br /> <br />. <br /> <br />The next step will be to add a new future use to all four models (the original monthly model as well as <br />the three daily models). For the monthly model, results will be distributed to daily following the <br />historical distribution of daily flow across the month, as currently done by USFWS. Daily gage flows <br />from the four models will be compared to determine which are credible and whether differences among <br />the results are significant. <br /> <br />I. Download the current databases for Division 6. Download the most recent version of Statemod and <br />all DMl's. This sub task is budgeted to allow for software and/or system difficulties, to the extent that <br />it would require approximately three days' effort by an associate engineer with direction and <br />oversight by the project manager. <br /> <br />2. Create a monthly model of the Elk River from the existing Yampa nIb model from the headwaters to <br />the Clark gage. This river reach was selected because it contains two reservoirs, two instream flow <br />rights, and several diversion structures. The study period will be 1975-1991, a span within the mod.el <br />calibration period during which the gage record is complete. <br /> <br />3. Create a daily model by having Statemod disaggregate monthly baseflows, diversion demand, <br />instream flow demand, and reservoir targets, by setting them to an average daily value (station <br />c...idy variables set to 0). Monthly return flow fractions will be converted to daily values that effect <br />the same total return over the month, as described in Task 1. Execute the Calculated data set for <br />1975-1991 and compare gage flows at Clark with historical daily gage records for 1975-1991. <br /> <br />4. Create a daily model by having Statemod disaggregate monthly baseflows at the Clark gage by using <br />the pattern provided by the historical stream gage. Allow Statemod to disaggregate diversion <br />demand, instream flow demand, and reservoir targets by setting them to an average daily value, as in <br />subtask 3 (station c...idy variables set to 0). Monthly return flow fractions will be converted to daily <br />values that effect the same total return over the month, as described in the previous task. Execute the <br />Calculated data set for ]975-199] and compare gage flows at Clark with historical daily gage <br />records for ]975-1991. <br /> <br />5. Create a daily model by generating daily baseflows from daily gage records and historical diversion <br />records as available from the database. Dai]y reservoir content will be created by straight-line <br />interpolation between end-of-month content data. Monthly return flow fractions will be converted to <br />daily values as in the other two daily pilot models. Execute the Calculated data set for 1975-1991 <br />and compare gage flows at Clark with historical gage records for 1975-1991. <br /> <br />Note that $tatemod will need to be modified to conduct baseflow calculations on a daily basis for <br />this model. <br /> <br />6. Add a future demand to the Calculated data set for all four models (the monthly model and three <br />types of daily models). The monthly model will be executed and the resulting monthly gage flow at <br />Clark will be disaggregated to daily using the Clark historic daily pattern to distribute simulated <br />gaged flows. Compare these disaggregated Clark gage stream flows with daily streamflows from the <br />three daily models for 1975-1991. <br /> <br />7. Summarize the results of the calibration runs, focusing on the relative accuracy of the three <br />approaches to a daily model. Summarize the results of the future scenario runs, focusing on a <br />comparison between the current approach ofdisaggregating monthly results to daily, and each of the <br />three daily model approaches. <br />