FUTURE DIRECTION

The EAFB project team considers alternative covers a long-term ecosystem for flora and fauna, such as the endangered desert tortoise shown here.

By evaluating trends in predicting the performance of alternative landfill covers—estimated as a function of one or two important parameters (cover thickness, for example)—site engineers and regulatory analysts gain better footing in negotiations to select a mutually acceptable design. If the range and increment in the design parameters are chosen carefully, the results of the DSA indicate when (1) parameter values and closure designs lead to clearly inadequate performance, (2) benefits are realized by a given increment in a parameter value or design element, and (3) changes in a parameter value or design element result in no further improvement in cover performance. The results of this analysis can be used at any site on EAFB, but the approach should be applicable to any facility in the arid or semi-arid southwest.

Finally, the research team views the alternative landfill covers as ecosystems having components that function properly to maintain the desired water balance. Integral to this approach is a designed soil profile that includes native plant species that will thrive in the constructed system. Functional requirements imply the use of native species for the plant communities, suggesting the possibility of designing the cover to serve as habitat for native fauna including the endangered desert tortoise. This approach of site characterization and numerical simulations is not limited to analyses of alternative-cover designs. It can be used to study the design limits of other constructed ecosystems, such as those damaged by urban development or other anthropogenic activities. DRI faculty anticipate applying this new tool to other ecosystem restoration projects in the desert southwest that could benefit from linking soils, plants, and climate to create synergistic, self-sustaining environments.