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Proposal - Engineer...., Proposed Coffinto~ ~ June 8, 1981 Geologic Feasibility Study /. and Reservoir Site , Page 2 to invite troublesome remedial work at the least and total dam failure, such as the Teton dam of Idaho in 1976, at the most. Thus it can be seen that the most expedient approach, both technically and financially, is to begin with a sound geologic knowledge of the area of the proposed dam. A review of information already available has shown that this north central area of Boulder County, Colorado, where'the Coffintop dam is planned to be located, is geologically very complex. Therefore it is doubly true that money spent at the "front end" of this project will indeed be well invested. The following proposal, has been developed to ascertain the essential amount of geological detail from a surficial examination of the site, confirmed by a limited number of strategically located exploratory drill holes. From the knowledge gained therefrom, a plan will be developed for the next, more explicit investigation that should be made prior to any actual design work. PURPOSE OF STUDY The overall purpose of this Study is to assess from 'the surface, aided by a few strategic exploratory drill holes, the geological conditions at the proposed site for the Coffintop dam and reservoir in such detail that the general geologic feasibility of this dam can be determined. It 11i11 also provide the basis for designing an efficient and more comprehensive subsurface exploration program to investigate foundation conditions. In the experience of this Consultant such preliminary examination is essential in order to determine, from the outset of the project, the probable conditions that will be met in further study, design, and planning, in order to avoid such costly occurrences as unprofitable trial-and-error drilling, or over-design. Such geological assessments shall be based solely on data derived from (1) existing, available geological literature; (2) surficial geological data; and (3) preliminary subsurface geological information as will be available from drilling and logging a limited number of strategically located exploratory drill holes along the axis of the proposed dam. These data will be gathered by the Consultant as described in the section, SCOPE OF SERVICES, below. For purposes of delineation of the Study Area it has been presumed that the angles of inclinati?n of both the upstream and downstream slopes of an earthfi11 dam at the site would not be flatter than a gradient of 3 horizontal to 1 vertical. UEBLACKER ASSOCIATES. INC.