Earth fissures are a significant threat to various types of infrastructure in the Southwestern United States and elsewhere in the world. They are caused by differing subsidence rates and magnitudes associated with groundwater pumping in alluvial basins. In this paper, Ravi Murthy and his co-author Jon Benoist, both with the Arizona Department of Water Resources, examine the impact that earth fissuring has on embankment dams used for flood control. One of their main dilemmas as regulators is: "Is it possible to safely rehabilitate dams in fissure risk zones to continue to provide economical flood protection to the public, or does the risk of dam failure due to an undetected fissure present too great a threat to the public?" Check out the HTML Version. 

By Robert Cummings or presentation at the 53rd Highway Geology Symposium, San Luis Obispo, CA, August, 2002.

Highway development projects crossing lands with special scenic or recreational characteristics may be required to meet special aesthetic criteria. Generally, the entity imposing the aesthetic criteria is external to the core roadway construction team. Usually, agencies imposing these criteria are land administration entities, external to highway departments, whose primary role is the preservation of historical or recreational opportunities, such as the Bureau of Land Management, the National Park Service, the United States Forest Service, or local governmental agencies with similar responsibilities. However, agencies imposing aesthetic criteria may also be divisions of highway development agencies themselves. For example, in Arizona, the Roadside Development section within the Arizona Department of Transportation has defined aesthetic needs on numerous designated scenic highways.

Aesthetic attainment on highway jobs falls in the category of what many term “soft engineering”, whose design is, in large part, intuitive. This contrasts strongly with the “hard engineering” elements (structures, pavement, line and grade, and so forth) whose design is deterministic and more familiar to roadway designers and builders. From the perspective of the highway designer and constructor, the imposition of unfamiliar and sometimes vague design and construction criteria, by external entities whose approach differs greatly from that of engineers, can be problematic. The aim of this paper is to describe how geology, construction engineering, and visual analysis have been used to alleviate and streamline the process of aesthetic attainment.