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<br />lengths of predicted debris now nm outs on the FLO-2D simulation. The debris now nm <br />out distances predicted by FL.O-2D do not reach the end of the historic debris now fan on <br />the Wulfsohn fan area. As run out distance is highly dependent on sediment <br />concentration in FLO-20, the maximum run out distance may be altered by varying the <br />volumetric sediment concentration in future model runs. <br /> <br />Modeled vs Measured Debris Flow Depths, <br />9-10-03 Event, Coal Seam Fire <br /> <br /> 160 <br />'" <br />.l: 140 <br />- <br />c- <br />" <br />0 120 <br />~ <br />0 100 <br />LL '" <br />'" " <br />-;: .l: 80. <br />.c u <br />" c: <br />0 60. <br />-0 <br />" 40 <br />~ <br />" <br />'" <br />'" 20 <br />" <br />~ <br /> 0 <br /> 0 <br /> <br /> <br />. Channel Depths <br /> <br />. <br /> <br />. Flood Plain Depths <br /> <br />- Measured=Modeled <br />Data <br /> <br />. <br />. <br /> <br />~:' .. -". <br /> <br />50 <br /> <br />100 <br /> <br />150 <br /> <br />200 <br /> <br />Flo-2D Depths inches, 100 yr <br />Storm <br /> <br />Figure 4. Modeled debris flow depths plotted with measured debris flow depths for debris <br />now events that occurred on September to, 2003. <br /> <br />Conclusions and rccol11l11cnd:Uions: <br /> <br />The methodology for the FLO-2D simulations that were run by the USGS appears <br />to have been executed to the highest standards for this type of hydrologic modeling. A <br />field reconnaissance of the Manning surface roughness ofchanncls conlinned that the <br />values used in the model were within acceptable limits. While the data collccted for this <br />report show that some of the debris now depths that have occurred in recent storm events <br />exceed the depths predicted by FLO-2D, this may be explained by the fact that many <br />measurements were located in incised channels that would not show up on the 10 meter <br />OEM's lIsed for the FLO-2D simulations. <br />