Rio Nuevo North: Buried Landfill Delineation with IP

Induced polarization (IP) and resistivity can be very useful tools in mapping environmental features such as buried landfills, but the survey speeds and pseudosection interpretations have been drawbacks. New multichannel receivers with computer-controlled multiplexers now allow extremely fast data acquisition, and two dimensional smooth-model inversion (with topography) provides realistic geo-electric cross sections that allow for the interpretation of the edges of buried landfills, thickness of soil cover, and thickness of waste material.

Historical records indicate that the Rio Nuevo North Landfill was probably comprised of multiple, irregularly shaped pits resulting from clay, sand, and gravel mining. Several deep and numerous shallow pits, evident from aerial photographs, have been filled with construction debris, landscaping waste, and municipal solid waste. Haphazard cleaning of the area in the early 1980's left pockets of garbage in the subsurface below 17 feet. The result of the excavation and fill activity is an area that may or may not contain small pockets of waste material.