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.-A <br /> February 16, 2012 <br /> Project: Inundation Mapping for The Consolidated Mutual Water Company <br /> Vendor: The Consolidated Mutual Water Company; 12700 W. 27th Avenue; Lakewood, CO 80215 <br /> Phone: (303) 274-7401 <br /> c/o Mr. Mike Queen <br /> Consultant: J&T Consulting; 1400 W. 122nd Avenue, Suite 120; Westminster, CO 80234 <br /> Phone: (303)457-0735 <br /> c/o Mr.Jason Murray <br /> CWCB funding source: Severance Tax Trust Fund Operational Account <br /> SCOPE OF WORK <br /> J&T Consulting(Consultant), at the direction of The Consolidated Mutual Water Company(Vendor), will <br /> perform a dam breach modeling study and flood inundation mapping for two dams within the Vendor's <br /> system. The study shall be in accordance with the latest Breach Guidelines published by the Colorado <br /> Dam Safety Branch. The level of analysis shall be "Simple," as defined in Table 1 of the Guidelines for <br /> both the breach modeling and flood inundation mapping. Flood routing models and inundation <br /> mapping shall be based on USGS 10-meter Digital Elevation Model (DEM) or best available topographic <br /> mapping. Field measurements of bridges and culverts at critical sections shall be incorporated into the <br /> model as necessary. The limits of the dam breach flood mapping shall extend from reservoir/dam, <br /> downstream to the location where breach flood impacts become negligible. <br /> The two dams to be modeled are Fairmount Reservoir and Maple Grove Reservoir. The downstream <br /> limit of the inundation mapping for both reservoirs is expected to extend to Clear Creek, in the vicinity <br /> of the 1-70 and US Highway 58 interchange. Preliminary results will determine if additional modeling of <br /> Clear Creek 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 each dam and route the resulting <br /> outflow hydrographs downstream using HEC-HMS. Breach parameters shall be estimated in accordance <br /> with 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 />