at the surface 19 has the advantage of not having to excavate to perform the tests and it provides venting rate information very close to where actual collection of the gas will occur the gas venting rate can be determined in accordance with various known techniques for example landfill gas has an odor and so relative gas venting rates can be determined by smelling with the more odiferous regions being regions where the gas venting rate is higher another way to determine the gas venting rate is to use a methanometer for this purpose a flux box having an open bottom is placed on the surface at which it is desired to determine the gas venting rate and the landfill gas is allowed to flow into the flux box the methanometer then provides a read out indicative of the landfill gas venting rate after the survey of gas venting rates has been completed the shallow wells 13 are located at the regions having the desired landfill gas venting rates typically the regions selected for one of the wells 13 will have an above average landfill gas venting rate for those regions surveyed and wells may be located at the regions having the maximum gas venting rates after the site for the shallow well 13 has been selected the cover material 17 is excavated from the selected region of the landfill 11.