REMOTE-SENSING TO ASSESS LANDFILL GAS MIGRATION

Remote sensing is proposed as a useful technique for monitoring landfill sites for gas migration. Landfill gas has the potential to migrate from the site boundaries and cause damage. It is also spatially and temporally very difficult to monitor. The presence of landfill gas in the root zone causes signs of stress to be visible within the vegetation, the stress generally taking the form of chlorosis or dieback. This, in turn, may result in a change in spectral response of the vegetation. Airborne thematic map data and low cost video imagery are proposed as techniques to obtain imagery in order to classify sites according to vegetation stress. A comparison between the efficiency and costs of the two sources of imagery is made. Two case studies are summarized and the economics of the methodology discussed. It is recommended that remote sensing is used in conjunction with soil and geological maps to identify areas of high landfill gas concentration and that this is combined with traditional field measurements to gain a better spatial and temporal understanding of gas migration.