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Management of Commercially Generated Radioactive Waste - U.S. ...

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B.3<br />

Erosion by wind energy is a mechanical process. It requires the environmental condi-<br />

tions <strong>of</strong> no vegetation and uncemented dry earth materials (Verhoogen et al. 1970). These<br />

conditions are most prevalent in desert environments. Depth <strong>of</strong> possible wind erosion is<br />

controlled by wind velocity, duration, and other climatic conditions (Office <strong>of</strong> <strong>Waste</strong><br />

Isolation 1977).<br />

Mass-wasting, or gravitational erosion, is the movement <strong>of</strong> earth materials by gravity<br />

independent <strong>of</strong> water, glacier, or wind. The significance <strong>of</strong> mass-wasting is that it affects<br />

the whole body <strong>of</strong> the earth material and is not confined to a land environment. Mass-<br />

wasting occurs when the force <strong>of</strong> gravity on a mass <strong>of</strong> earth material exceeds the cohesive<br />

strength between the individual earth particles. Environmental components important to the<br />

mass-wasting process are weathering, geomorphology (topography), processes <strong>of</strong> stream, gla-<br />

cial, and wind erosion and sometimes earthquakes (Claiborne and Gera 1974).<br />

Surface geologic processes cause the transport <strong>of</strong> earth materials to sites <strong>of</strong> deposi-<br />

tion. Rates <strong>of</strong> deposition may be as imperceptibly slow as rates <strong>of</strong> erosion. However, they<br />

also may be significant over hundreds <strong>of</strong> thousands <strong>of</strong> years. Agents <strong>of</strong> deposition that<br />

should be evaluated for candidate repository site regions include run<strong>of</strong>f and streams, wind,<br />

glacial processes, and volcanism. A surface environment conducive to long-term deposition<br />

is somewhat favorable to repository containment because as the depth <strong>of</strong> sedimentary cover<br />

continually and gradually increases, so would the depth <strong>of</strong> burial.

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