Logan Canyon is located east of Logan, Utah, in the Bear River Range. The lower part of Logan Canyon is considered that section of the canyon from its mouth upstream to Tony Grove Canyon, a distance of 22 miles, Figure 1 Some tributary canyons of the lower part of Logan Canyon have been included in this investigation because of their relationship to Logan Canyon. Grassy Flat Canyon, a south tributary of Logan Canyon 4.4 miles from Logan, exhibits several geomorphic features related to the geology of Logan Canyon. Because of its extensive use and close association with Logan Canyon, Tony Grove Canyon is also included. Tony Grove Canyon extends from Logan Canyon northwestward to the crest of the Bear River Range, a distance of about six miles. More than 20,000 feet of Paleozoic rocks ranging in age from Cambrian to Pennsylvanian are exposed in Logan Canyon . Cenozoic deposits are widespread in and near the canyon. The crest of the Bear River Range near Naomi Peak and Tony Grove Canyon was the center of glacial activity during the Pleistocene. During the glaciations of Tony Grove Canyon, Lake Bonneville extended into Logan Canyon and influenced the geomorphic development near the mouth of the canyon. Logan Canyon is vital to the economy of Cache Valley. The canyon is a large part of the Logan River watershed. Logan River passes through three hydroelectric plants in Logan Canyon and supplies culinary and irrigation water for the valley below. Animals and plants of a wide variety are abundant, providing fishing , hunting, and a harvest of forest products. U.S. highway 89 traverses the canyon and carries a large volume of traffic to points within the canyon, as well as to other areas. Logan Canyon is entirely within the Cache National Forest. Improved campsites and recreational facilities, which were used by almost 1.5 million visitors during 1963; according to the U. S. Forest Service, are located throughout the Canyon. Increased recreational and travel use of the canyon has resulted in a demand for more geologic work in this area .

It has been estimated that approximately fifty percent of the United States’ population lives behind levees. Because these earth structures are typically long, subjected to seasonal changes and spatial variability, it is logical to analyze them in an uncertainty-based approach. This research is focused on assessing the potential of internal erosion related failure due to underseepage with the general objective of assessing the failure potential of individual geomorphic features while considering length effects. The project team was granted $204,000 from the National Science Foundation and $10,000 from the United States Society on Dams which resulted in research collaboration within graduate students and University of Delaware faculty as well as several presentations in prestigious conferences (in the U.S and Europe) and publication of journal papers. Findings from this research should be easily transferrable to other linear earth structures (such as dams, construction excavations, detention ponds, road embankments, etc.), and should significantly enhance reliability analysis across a wide array of structure types and geologic settings allowing a broad impact on future research, as well as geotechnical engineering practice.