General subsoil conditions conssist of lacustrine deposits of layers of sand, silts and clays overlying stiff glacial till soils. the soils are badly weathered and desiccated to a depty of approximately 15 feet.
The glacial till underlying the entire site consists of stiff to very stiff, silty clay containing gravel and coal particles. Pockets and layers of sand are located within the glacial till deposit.
The long-term static groundwater table at the site is located at depth. Temporary perched water tables may be encountered across the site as a result of leakagae from water storage facilities and irrigation canals and movement of runoff towards the adjacent river valley.
C. Coulee Stability
The natural slopes of the erosion gullies of the east side of the proposed Univeristy site range from 2.0 to 3.5 horizontal to 1 vertical. There is evidence of surface creep movement and shallow slump movements along the gullies in both Sections 24 and 25. Observations and slope stability analyses indicate that agully slopes having a gradient of 2 horizontal to 1 vertical, or flatter, are generally stable.
Water erosion is of great concern. The existing native vegetation at the bottom of the gullies should be left undisturbed and consideration should be given to the establishment of additional drought-resistant vegetation.
E. Mine Locations
Abandoned mines are located to the north and far to the south of the site, as indicated in Figure 8. Examination of all available data indicates that mined areas in Section 35 are the nearest to the University site and that mined areas do no occur at the site.