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<br />~ <br /> <br />Corps Response #3. <br /> <br />Our analysis used the streamflow records <br />referenced report. <br /> <br />in the <br /> <br />CWCB Comment #4. <br /> <br />What parameters were used for the synthetic rainfall <br />analysis (SWMM)? No tabulations or documentation were <br />provided regarding rainfall distribution, drainage area, <br />rainfall rates, etc. <br /> <br />Corps Response #4. <br /> <br />A table has been added to our revised report which <br />contains the synthetic rainfall values used in the SWMM. <br /> <br />CWCB Comment #5. <br /> <br />What was the period of record for the stream gage <br />analysis? No tabulation of peak flows was provided. We would <br />like to see documentation of which peak flows were included in <br />your analysis and which were not. We suggest a tabulation, <br />such as that described in the above report by the USGS, be <br />included in the final report. <br /> <br />Corps Response #5. <br /> <br />The requested information has been added to Appendix A in <br />the revised report. <br /> <br />CWCB Comment #6. <br /> <br />On what basis was the 1982 paper by Jarrett and Costa <br />used to calibrate your analysis? One thing that surprised us <br />was the substantial difference between the results in your <br />analysis and previously designated and approved flows from <br />Flood Insurance Studies in various Clear Creek County <br />communities (see attached table of FEMA flows and COE flows). <br />Why were those studies not considered while the Jarrett/Costa <br />paper was accepted as a valid calibration tool? <br /> <br />Corps Response #6. <br /> <br />Our revised studies did not use information in the 1982 <br />paper by Jarrett and Costa for calibration. Rather, the SWMM <br />model was calibrated to the rainfall discharge frequency <br />relationship at the Lawson gage which was derived from data <br />contained in the USGS Open File Report 82-426. <br /> <br />3 <br />