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<br />2.1 <br /> <br />II. SCOPE OF WORK <br />The scope of this supplemental study to delineate the flood-hazard areas <br />on the Cornet Creek alluvial fan in the town of Tenuride was designed to provide <br />a deta 11 ed assessment of flood i ng conditions near the apex of the fa,n where <br />Cornet Creek debouches from the watershed canyon. The analysis is intended to <br />address concerns expressed by FEMA and the to~m of Telluride regarding the <br />adequacy of the topographic data used to prepa~e the draft report for the study <br />(SLA and O'Brien, 1989). To improve the delineation of flood hazard on the <br />alluvial fan within the town 1 imits, the town :ollected and provided to SLlI <br />additional survey data for the fan apex area topography (Town of Tenuride, <br />1989). SLA was requested by FEMA to conduct furt.her hydrau'l ic analyses of the <br />IOO-year return period water flood and mud now with this new survey data and <br />to complete the Flood Insurance Study of Cornet Creek for the town of Telluride_ <br />The specific tasks conducted as part of this supplementa-I analysis project <br />included: <br /> <br />Hydraulic Analysis <br />Maximum flow depths, velocities and areas 0= inundation were predicted for <br />the IOO-year return period water flood and mud flow using a 2,dimensional flbw- <br />routing model (MUDFLOW). The water floods and hyperconcentrated sediment flows <br />were routed through a detailed 25,foot square grid element system of the fan apex <br />considering new survey data. The outflow dischar~;e from the detailed grid system <br />at the fan apex was then used as input for the simulation of the IOO-year event <br />over the remainder of the alluvial fan and the town of Telluride using the same <br />data base described in the draft study report_ <br /> <br />Flood-Hazard Mavvinq <br />The results of the hydraulic analysis were used in the preparation of the <br />flood-hazard maps delineating areas of maximur~ flood depths, maximum flow <br />velocities and areas of inundation for the 100-year flood event. <br />