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I I I I The Big Thompson flood plain generally is narrow (100 to 150 feet) and between steep rockfaced slopes. The normal river channel is only 10 to 30 feet wide, and only a few feet deep. Locally, the flood plain expands into broader park-like areas. The generating station and reservoir sites are located in two of those park-like areas. I I I The Front Range of the Colorado Rockies is a regional north-south trending uplift corded by Precambrian-age crystalline metamorphic and igneous rocks, and bounded by north- south trending faults. Those rocks were mantled originally by a several thousand feet thick sequence of sedimentary rocks, but that have been eroded away except within localized structural basins. The metamorphic rocks, the oldest rocks exposed within the Range, are primarily mica schists and gneises, but include pods and amphibilite, a black crystalline igneous rock resembling basalt. I I Those metamorphic rocks have been complexly intruded by masses of granitic rocks, mainly tonalite and granodiorite, but also granite pegmatites. The intrusions range in size from a few square inches to several square miles in areal extent. Contacts between the intrusions and the invaded metamorphic rock typically are complex. I I Following the Big Thompson flood, heavy earth moving equipment was used extensively to rehabilitate the highway and to assist in search operations. As a result, much of the material in the flood plain was disturbed and reworked during the cleanup effort. The fill ranges generally from sand to boulders and is essentially unstratified. I I The climate of the project area is very similar to that of Loveland, 13 miles away. The following is a summary of weather data for Loveland which closely approximates that at the project site. I I I LOVELAND CLIMATE INFORMATION Record high and low temperatures: MONTH DATE HIGHEST TEMP. DATE I January 1888 1954 71 75 1930 1951 LOWEST TEMP, -38 I I February -41