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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />II <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />. The Northwest Parkway (new version of the old W-470 that got voted down previously) will <br />cross Rock Creek, but this will be south of Lafayette. <br /> <br />. The old SCS floodplain studies were used as the basis for some of the FEMA mapping, but <br />there are busts in elevations in some of the studies that make them hard to use to set building <br />pad elevations (or they may have used a different elevation datum). Tom suggested using the <br />depths from the profiles to set building elevations if there is concern over the flood elevations <br />themselves. <br /> <br />. Dillon Street is mis-marked on the FIRMs. What is shown as Dillon Street is actually Empire <br />Street. Dillon is a mile to the south. <br /> <br />Field Review <br />. A field review was conducted on November 30, 2000 with the following objectives: check on <br />specific questions that arose during the FIS/FIRM review, insure that watersheds for which <br />hydrology estimates were performed meet the limitations of the equations and field verify <br />approximate floodplain determinations. <br /> <br />. Geer Canyon: The abundance of rocks in the channel and floodplain is evidence of heavy <br />runoff causing debris flow in Geer Creek. Floodflows are likely contained within the <br />channel and the floodplain between the road and channel. The area is heavily grazed. The <br />watershed is undeveloped, with a natural area at its headwaters. <br /> <br />. A very high roughness range was reported in the FIS for James Creek (0.030 - 0.750). Field <br />observations show that the channel roughness is not nearly this high. The value reported in <br />the FIS is likely a misprint, and should be 0.075. <br /> <br />. There were several areas where railroad crossing structures were not shown in the channel <br />profile. It was verified that these crossings generally do have some sort of crossing structure <br />and they are simply not shown on the profiles. However, some of these structures are small, <br />and overtopping of the railroads may occur. <br /> <br />. Gregory Creek, Kings Gulch, and Bluebell Canyon Creek: All of these are confined channels <br />that flow through highly urbanized areas. They flow through backyards of homes, and often, <br />are umecognizable as channels. Culverts mayor may not be existent. The floodplain extents <br />shown on the FIRMs assume that the flow remains within the channels. However, there are <br />several locations where flows could leave the channels and cause shallow flooding <br />elsewhere. There is a significant amount of debris that could clog conveyance structures and <br />result in rerouting of flows. <br /> <br />. Development is primarily occurring in communities southwest of Boulder along Highway 36 <br />and around Longmont. <br /> <br />G> <br /> <br />2019 <br /> <br />boulder_co _fieldrpt.doc <br />November 13, 2000 <br />