GEOTECHNICAL ENGINEERING CHALLENGES IN SOUTHWEST COLORADO AND WHAT THE FUTURE MAY HOLD CONSIDERING CLIMATE CHANGE

From the time of the early miners, pioneers and farmers there have been engineering challenges to the settlers of southwestern Colorado. Examples of such early feats are the Gunnison Tunnel, the Million Dollar Highway over Red Mountain Pass from Ouray to Silverton, the Denver & Rio Grande Narrow Gauge Railroad, and the extensive hardrock mining of the San Juan Mining District. However, due to recent development pressure, high land values, the need to maximize square footage, and the feeling that money can solve any problem, even the most difficult sites are being built upon. This development pressure has presented challenges to geotechnical engineers and contractors, including deep and vertical excavation shoring, dewatering, and slope stabilization. Additionally, construction in rockfall zones, on active debris fans, on unstable slopes, in areas of expansive soil/rock or hydrocompactive soils, below the water table, and in remote areas has become the norm, not the exception. We have seen relatively new technologies, such as micro-piles, used very effectively in highly variable and even saturated conditions for deep foundations, tie-backs, and soil nails. There are also more computer models available today that serve as useful tools for assessing the level of geologic hazards and the effectiveness of various mitigation methods.

Due to the pace of development, some hazards have been overlooked or at least downplayed. As engineers and geologists we can't be caught by the same complacency, especially when considering the effects that continued global warming has on the stability of natural systems. A review of research on the potential impacts of climate change on the economies, agriculture, hazards, and land use in Colorado and neighboring states has determined some common threads. In general, continued global warming is expected to change the pattern and intensity of precipitation and dry cycles. Regional predicted climatic changes will be discussed along with the implications to geologic hazards, including the increased potential for flooding, debris flows/mudflows, avalanches, rockfalls, and landslides.