Geologic features at Bonny Damsite consist of the following;1)Valley fill alluvium to depth of 15-20 feet, stream deposited material consisting mainly of silt, sand and gravel.2)Valley sides of soft Ogallala sandstone encountered beneath the alluvium is a fairly impervious material, lightly cemented and fine sand in grade size. 3)A loess mantle over the high land, which varies from silt to silty f