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<br />- <br /> <br />, <br />7, 15,30 and 60 days. The HEC-STATS prpgram will be used to compute the <br />statistics for all durations used in the analys~s. Statistics will be smoothed using <br />the procedures outlined in EMIII0-2-1415 in order to prevent the probability <br />curves from crossing at infrequent events. : <br /> <br />3. Historical Flow Volume Probability Analys~s. This task will be similar to task 2 <br />except the recorded historical flows at the Chatfield site will be used in the <br />volume probability analysis. Results of this analysis will be compared to the <br />natural flow volume probability analysis. <br /> <br />4. Historical Precipitation Database. Historical, precipitation data for stations located <br />in and near the South Platte River basin will :be obtained and stored in an HEC- <br />DSS database. Missing records will be filled in using the inverse distance squared <br />weighting method. Once the missing records are filled in statistics will be <br />computed as well as ratios of antecedent precipitation to "main event" <br />precipitation for durations up to 15 days prior each event. This analysis will <br />evaluate main event precipitation amounts exceeding 1 inch, 2 inches, 3 inches, 4 <br />inches, 5 inches and greater than 6 inches. Results of this analysis will be <br />summarized in graphically and in tables. <br /> <br />5. Monte Carlo Simulation of Precipitation. Monte Carlo simulation of daily <br />precipitation will be accomplished to evaluate long-term sequences of future <br />precipitation events using statistics computed in task 4. Various simulations of up <br />to 100,000 year long traces will be analyzed to determine the likelihood of severe <br />combinations of antecedent and main precipitation events. <br /> <br />6. Monte Carlo Simulation ofInflow. Natural inflows developed in task 1 will be <br />used to compute statistics to be used to extend streamflow records stochastically <br />for up to 100,000 years using Monte Carlo simulation techniques. Volume <br />probability relationships will be computed from these results and compared to <br />those developed in tasks 2 and 3. <br /> <br />7. Report Preparation. A detailed technical report will be prepared to document the <br />study objectives, data used, methodologies, results and conclusions of the study. <br />Charts and tables will be prepared to summarize the results and compare the <br />evaluations of the natural and historical, inflow probabilities. Charts and tables <br />will also be prepared to summarize the precipitation analysis and the Monte Carlo <br />simulation results. Sources of data used in the analysis shall be referenced in the <br />report. <br /> <br />8. Meetings & Coordination. This task will include in-house meetings with the <br />study team as well as meetings with the study sponsor, the NWS, and Corps <br />Northwestern Division and Headquarters staff It is anticipated that there will be <br />at least three meetings with the sponsor during the course of the study. <br /> <br />2 <br /> <br />