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March 1, 2013 <br /> Project: Inundation Mapping for Santa Maria Reservoir Company <br /> Vendor: Santa Maria Reservoir Company; P.O. Box 288; Monte Vista, CO 81144 <br /> Phone: (303) 451-7604 <br /> c/o Mr.Jay Yeager <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 funding source: Severance Tax Trust Fund Operational Account <br /> SCOPE OF WORK <br /> Deere &Ault Consulting, Inc. (Consultant), at the direction of the Santa Maria Reservoir Company <br /> (Vendor), will perform a dam breach modeling study and flood inundation mapping for two dams within <br /> the Vendor's system. The studies shall be in accordance with the latest Breach Guidelines published by <br /> the Colorado Dam Safety Branch. The level of analysis shall be "Simple," as defined in Table 1 of the <br /> Guidelines for both the breach modeling and flood inundation mapping. Flood routing models and <br /> inundation mapping shall be based on USGS 10-meter Digital Elevation Model (DEM) or best available <br /> topographic mapping. <br /> The two dams to be modeled are at Continental Reservoir and Santa Maria Reservoir. The downstream <br /> limit of the inundation mapping for Continental Reservoir will extend along Clear Creek from the dam <br /> down to the Rio Grande confluence, and further downstream of the Rio Grande to where breach flood <br /> impacts become negligible. The inundation mapping for Santa Maria Reservoir will extend from the <br /> dam, down the outlet channel, Boulder Creek, Clear Creek, and to the confluence with the Rio Grande. <br /> The mapping will then follow the Rio Grande downstream to a point where the flood impacts are <br /> negligible. Mapping of both reservoirs will terminate at or before the Colorado-New Mexico state line. <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 />