(A) When we consider the geological history, we begin to understand the significant variations of the geological formations in our county and their impact on future development.
(B) Cache Valley is a high mountain valley surrounded by the Bear River Range of the Wasatch Mountains on the east, with peaks rising to 10,000 feet, and the Wellsville and Malad Ranges on the west.
(C) The Utah/Idaho border cuts the valley approximately in half with Franklin County, Idaho located in the north end. Preston, the county seat, has an elevation of 4,710 feet, and average annual rainfall of 16.5 inches and a growing season of 123 frost-free days.
(D) The mountain ranges bordering the west, east, and north sides of our county have peaks reaching close to 10,000 feet in elevation. The valley floor ranges between 4,500 feet to 5,100 feet. Franklin County and most of Cache Valley came into its present form through structural faults and adjustments by the shifting and settling of the valley. The valley floor soon was below the drainage outlet of the valley, therefore, it filled with water even prior to the Lake Bonneville Era.
(E) The Lake Bonneville Era occurred during the Pleistocene or Glacial Epoch when the climate was cooler with increased rainfall and decreased evaporation. The stream flows were greatly enhanced and this condition continued for thousands of years. The lake covered the entire Cache Valley, extending north to Red Rock Pass and Swan Lake and up through the Bear River Canyon nearly to Grace, Idaho. The surface of the lake reached an elevation of 5,150 feet, had a maximum depth of 1,080 feet and at its highest level it covered 19,750 square miles with approximately 2,500 miles of shoreline.
(F) Due to the action of this large lake, peat beds were buried and sand deltas were formed. As the lake receded the natural streams flowing from the canyons deposited their loads of sand, gravel, and soil to form the deltas at the mouth of each stream, the Dayton bench, and the bench on the east side of the Bear River.
(G) The formation of deltas, as described, has created geological conditions which must be addressed when considering locations for the construction of homes, industrial sites, domestic and irrigation water systems, septic or waste disposal systems, and roads and bridges. Hazardous building conditions, high mineral content water sources, and soil percolation factors must all be considered in the County Comprehensive Plan and its Development Code.
(Ord. 2007-8-13B, passed 8-13-2007)