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February 16, 2012 <br /> Project: Inundation Mapping for Fuchs Ranches, Inc. <br /> Vendor: Fuchs Ranches, Inc.; 1620 County Road 14A; Del Norte, CO 81132 <br /> Phone: (719) 657-2519 <br /> c/o Mr. Michael Fuchs <br /> Consultant: Deere &Ault Consulting, Inc.; 600 S.Airport Rd, Building A, Suite 205; Longmont, CO 80503 <br /> Phone: (303) 651-1468 <br /> c/o Mr. Mark Severin, P.E. <br /> CWCB fundingsource: Severance Tax Trust Fund Operational Account <br /> SCOPE OF WORK <br /> Deere &Ault Consulting, Inc. (Consultant), at the direction of Fuchs Ranches, Inc. (Vendor), will perform <br /> a dam breach modeling study and flood inundation mapping for Fuchs Dam. The study shall be in <br /> accordance with the latest Breach Guidelines published by the Colorado Dam Safety Branch. The level <br /> of analysis shall be "Simple," as defined in Table 1 of the Guidelines for both the breach modeling and <br /> flood inundation mapping. Flood routing models and inundation mapping shall be based on USGS 10- <br /> meter Digital Elevation Model (DEM) or best available topographic mapping. Field measurements of <br /> bridges and culverts at critical sections shall be incorporated into the model as necessary. The limits of <br /> the dam breach flood mapping shall extend from reservoir/dam, downstream to the location where <br /> breach flood impacts become negligible. <br /> The downstream limit of the inundation mapping for Fuchs Dam is expected to extend down the East <br /> Fork of Pinos Creek and terminate in the Rio Grande River, approximately 1,000 feet downstream of Del <br /> Norte. Preliminary results will determine if additional modeling is required. <br /> The inundation limits shall be prepared in UTM coordinates (NAD 83, Zone 13—meters)which shall be <br /> overlaid on base mapping that includes color aerial imagery (2009 or newer). The inundation map shall <br /> be printed in color on a minimum sheet size of 11"x 17". The inundation extents shall be clearly <br /> illustrated and include 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 stations, <br /> etc.) shall be annotated and any roads expected to be overtopped by the flood wave shall be identified. <br /> The map shall include a legend noting the dam, DAMID, north arrow and a graphic scale. <br /> PROPOSED METHODOLOGY <br /> The Consultant shall perform a clear day dam failure analysis of the dam and route the resulting outflow <br /> hydrographs downstream using HEC-HMS. Breach parameters shall be estimated in accordance with <br /> methodologies recommended by the Office of the State Engineer, Dam Safety Branch. Hydraulic <br /> parameters, including width of flow, depth of flow and velocity at critical locations shall be estimated <br /> using the Corps of Engineer's HEC-RAS computer modeling software. A steady-state water surface <br /> profile resulting from peak flow rates at various locations shall be generated. Topographic information <br /> for the floodplains shall be based on USGS 10-meter DEMs from the National Elevation Dataset (NED) <br /> elevation data. <br />