The distribution and fate of residual radioactivity in earth moved by nuclear explosives are important considerations in nuclear civil engineering. The Sedan cratering experiment conducted in the Nevada desert provided a natural ecosystem in which to study these criteria. Radioecological studies conducted over a five-year period have characterized the distribution and residence time of tritium in the Sedan crater ejecta. These studies demonstrate that an ecological approach can provide descriptive and functional data that may be applied to the development of nuclear-explosive technology.