C150094 Phase I Report - Laserfiche WebLink

Home Browse Search

Long Hollow Dam and Reservoir Phase I Summary Report • U.S. Geological Survey. Geology and Fuel Resources of the Red Mesa Area, A, La Plata and Montezuma Counties, Colorado. 3.0 TOPOGRAPHY Pacific Western Technologies, Ltd. (PWT), under contract with LPWCD, obtained aerial photographs and generated color digital orthophotos and a digital terrain model for the LHR site. PWT flew the LHR site on February 23, 2002. Color stereo photographs, together with ground survey control points, were used to generate a topographic map of the site with 2-foot contour intervals (see Figure 3). PWT prepared electronic and mylar copies of LHR topographic mapping, as well as color digital orthophotos. This base mapping was used for various LHR Phase I feasibility study tasks, such as the geologic reconnaissance study, the wetlands delineation, the cultural resources evaluation, and the production of a reconnaissance-level opinion of cost(+/-50%). - 4.0 GEOLOGIC RECONNAISSANCE LPWCD contracted with Hepworth-Pawlak Geotechnical, Inc. (H-P) to perform a feasibility- level, engineering geology evaluation of the LHR site to determine geologic conditions that could have a major impact on project feasibility and to provide a basis for future design-level studies. After visiting the LHR site in January 2003, H-P prepared a report based on field observations, interpretation of aerial photographs, and H-P's experience with similar projects. The H-P report concluded that: • There were no indications of geologic conditions that would make the proposed dam and reservoir technically infeasible. • The proposed dam site and reservoir appear suitable for either an earth embankment or roller compacted concrete (RCC) dam. 991-077.115 Wright Water Engineers, Inc. Page 7 July 2004