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drawing showing pertinent information from the geologic map is attached hereto). Vegetation on the left side of the canyon is spazse, consisting principally of brush and shrubs with some aspen in pockets of deeper soil and where moisture is present. Outcrops of the Mesa Verde are visible on the right side of the canyon for the first 2000 feet of the proposed roadway. The remaining length along the right side is mapped as Quaternary unconsolidated Pleistocene deposits which have been derived from rocks of the Wasatch Formation and from intrusive rocks of the West Elk Mountains. The Mesa Verde Formation underlies these surficial deposits and it outcrops occasionally on the upper sides of the canyon wall. The unconsolidated deposits may be several tens of feet thick and generally lie at a shallower slope than the canyon wall on the left side of the gulch. The deeper soils support dense stands of timber and understory growth. This generally north-facing hillside holds considerable moisture and seeps are fairly common along the toe of the slope. The geologic map shows a normal fault running through the north-south section of Sylvester Gulch but no other structural features are noted. Bedding planes are generally horizontal. A drilling program undertaken by Agapito Associates, Inc. found the majority of bedrock fractures in the Sylvester Gulch area to run N62W with dips from 75 degrees SE to 85 degrees NW. The bottom of Sylvester Gulch consists of alluvial, colluvial, and fluvial deposits of soil and rock material produced through weathering of the adjacent hillsides. No test data regarding soil composition, consistency, and strength pazameters was available for the section of Sylvester Gulch to be traversed by the proposed road. A geologic hazazds assessment of the area has delineated the steep hillsides comprised of Mesa Verde Formation as being susceptible to rockfall while the unconsolidated material along the right side of the road alignment is shown as being potentially unstable. A landslide feature is identified within the unconsolidated material beginning at about roadway station 28+00 and ending near station 52+00. Examination of color infrared photograph collected in July of 1997 showed the natural slopes through the road route to be generally stable. Some minor slumps were evident, mostly southeast of the alignment, but no indications of recent slope failures were visible along the immediate area of the proposed alignment. A drawing showing the identified geologic hazards at Sylvester Gulch is enclosed. Buckhorn has conducted a preliminary analysis of hydrology based on the U.S. Army Corps of Engineers' HEC-1 model and type II runoff distribution from a 24-hour storm events with 25- year and 100-yeaz reoccurrence frequencies. This study, attached as appendix A, shows predicted peak flows for the upper section of the roadway as being between 17 and 43 cfs while the predicted peak flows for the lower section were found to be between 27 and 70 cfs. Design Considerations Based on our overview analysis, it was determined that an access road could be extended up Sylvester Gulch provided that low-impact techniques aze employed. That is, the site conditions while appazently stable must be viewed as being fragile and susceptible to disruption if addressed in a careless fashion. To prevent such disruption, the following design considerations are proposed: ~~ Sylvester Gulch Road Feasibility, Preliminary Report Job No. OI-345 Page 2 of 4