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DEERE & AULT <br /> CONSULTANTS,INC. <br /> December 16, 2011 <br /> Ms. Jill A. Baty <br /> The Highland Ditch Company <br /> P.O. Box 649 <br /> Mead, Colorado 80542-0649 <br /> Re: Proposal for Inundation Mapping for Highland Ditch Company <br /> Dear Ms. Baty: <br /> Thank you for giving Deere&Ault Consultants, Inc. (D&A) the opportunity to submit this proposal to <br /> the Highland Ditch Company (Company)for the preparation of dam breach inundation mapping for six <br /> of the Company's dams. We understand that the purpose of the breach modeling and the associated <br /> inundation mapping is for inclusion in the Emergency Action Plans for these reservoirs. This proposal <br /> is an update to our proposal dated July 7, 2011. The original proposal was for the dam at Foothills <br /> Reservoir and the two dams (North and South) at Highland#2 Reservoir. The scope and budget has <br /> been expanded to also include dams at McIntosh Reservoir,Highland#1 Reservoir, and Highland#3 <br /> 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 each reservoir downstream to where the <br /> breach flood impacts are no longer significant. The inundation mapping downstream from Foothills <br /> Reservoir is expected to extend from the dam down to the St. Vrain River and to the South Platte River <br /> with the emphasis on the reach between the reservoir and I-25. <br /> The Highland#2 Reservoir has two dams (North Dam and South Dam)requiring inundation mapping <br /> downstream from each. The inundation mapping downstream from the North Dam is expected to <br /> extend from the reservoir down to the Little Thompson River and to the South Platte River. Much of <br /> this inundation mapping follows the same flow path as the recently prepared inundation mapping for <br /> Ish Reservoir. This scope assumes that the base map, survey information, and hydraulic model used <br /> 600 S.Airport Road,Building A,Suite 205 <br /> Longmont,CO 80503 <br /> Phone: 303-651-1468• Fax: 303-651-1469 <br />