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3. Please refer to attached Exhibit B. The purpose of this spreadsheet is to take a specific look at each of the 25 properties along Gore Creek where structures are affected by the new floodplain. There are 4 comparisons of the adopted floodplain study vs. new floodplain study: · Base Flood Elevations · Stream Bottom Elevations · Change in Base Flood Elevation compared to Stream Bottom · Volume of flow for the 1 % annual chance flood Please note the following: · The BFE comparisons tend to fluctuate · The stream bottom elevations tend to fluctuate · From the Buffehr Creek confluence, upstream towards East Vail, there are several areas where there is substantial increases in the overall flood depth, even though the "a" is lower along the entire length of Gore Creek If the "a" has decreased along the length of Gore Creek, then why would there be ANY increase in BFE when compared to the currently adopted Floodplain Study? 4. Tributary topographic information is very general. How is it possible to determine the Flood Hazard Area when specific channel information is not available? See attached Exhibit F. Also, we have some x-section information on Middle Creek and Mill ~reek West. Should this info be incorporated into the model? (See Item 4 under "Specific Items") 5. . Along Gore Creek, the "Q" only increases 30 cfs at the confluence of Buffehr Creek, (2620 cfs upstream, 2650 cfs at the mouth of Gore Creek) while Buffehr Creek flows at 255 cfs. While we understand that "a" has a timing factor that needs to be considered, should the increase in volume along Gore Creek be greater? 6. Why does the Flood Hazard Area disappear at some bridge crossings and not others? Is it because the crossings are in culverts and not actual bridge spans? · Panel 468 - Buffehr Creek disappears under Circle Drive, but not under Chamonix Lane · Panel 469 - Red Sandstone Creek disappears under four crossings, not including 1-70 · Panel 469 - Spraddle Creek disappears once just before it goes under 1-70 · Panel 493 - Pitkin Creek disappears several times under short spans Specific Items 1. Panel 468: Buffehr Creek is shown overtopping Chamonix Lane. Is this really occurring? A new culvert was installed in 2000 that should be large enough to handle the 1 % annual chance flood. Also, The a has not changed from the 1983 Study, but FHA has shrunk significantly. At Circle Drive crossing, BFE has increased by 4 feet, yet FHA has decreased? See attached Exhibit F. 2. Panel 469: Red Sandstone Creek, on the north side of 1-70 - The FIRMs show an approximate increase in the BFE of 9', just upstream from culvert. This seems a bit excessive since the a has only increased by 30 cfs, and since a note indicates that the culvert will contain the 1 % annual chance flood. 3. Panel488: Mill Creek East flows into an 84" cmp culvert approximately 125 If upsteam of confluence with Gore Creek. Please refer to the attached Exhibit C. 4. Panel 488: Mill Creek West is shown flowing around bridge abutments that are approximately 150 If upstream of Hanson Ranch Rd (approx BFE = 8190). A floodplain analysis performed by Sato and Associates in September 2003 shows the bridge contains the 1 % annual chance flood. See attached Exhibit D.