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DEERE & AULT <br /> CONSULTANTS,INC. <br /> December 27, 2011 <br /> Ms. Cynda Lower <br /> Farmers' High Line Canal and Reservoir Company <br /> 725 Malley Drive <br /> Northglenn, Colorado 80233 <br /> Re: Proposal for Inundation Mapping for Hyatt Lake <br /> Dear Ms. Lower: <br /> Deere&Ault Consultants, Inc. (D&A)has been requested to submit this proposal to the Farmers' High <br /> Line Canal and Reservoir Company (Company) for the preparation of dam breach inundation mapping <br /> for the dam at Hyatt Lake. We understand that the purpose of the breach modeling and the associated <br /> inundation mapping is for inclusion in the Emergency Action Plans for this reservoir. <br /> SCOPE OF STUDY <br /> The scope of this study is to perform dam breach modeling in accordance with the latest Breach <br /> Guidelines published by the Colorado Dam Safety Branch. The level of analysis shall be "Simple" as <br /> described in Table 1 of the Guidelines for both the breach modeling and flood inundation mapping. <br /> Flood routing models and inundation mapping shall be based on the USGS 10-meter Digital Elevation <br /> Model (DEM) or best available topographic mapping. Field measurements of bridges/culverts at <br /> critical sections shall be incorporated into the model as necessary. <br /> The limits of the dam breach flood mapping shall extend from Hyatt Lake downstream to where the <br /> breach flood impacts are no longer significant.The inundation mapping downstream from Hyatt Lake <br /> is expected to extend from the dam down the unnamed drainage to Van Bibber Creek and terminate at <br /> the confluence with Ralston Creek. <br /> The inundation limits shall be prepared in UTM coordinates (NAD 83, Zone 13—meters)which shall <br /> be overlaid on base mapping that includes color aerial imagery(2009 or newer). The inundation map <br /> shall be printed in color on a minimum sheet size of 11"x17". The inundation extents shall be clearly <br /> illustrated along with peak discharge estimates, peak flood wave arrival times and peak flood wave <br /> depths at critical locations. Roads, highways and critical infrastructure (schools, hospitals,fire <br /> stations, etc.) shall be annotated and any roads expected to be overtopped by the flood wave shall be <br /> identified. The map shall include a legend noting the darn name and DAMID, a north arrow and <br /> graphic scale. <br /> 6(81 S.Airport Road,Building A.Suite 205 <br /> Longmont,CO 80503 <br /> Phone: 303-651-1468• Fax: 303-651-1469 <br />