Evaluation of Phase II Hydrogeologic Study for Garfield County

Evaluation of Phase II Hydrogeologic Study for Garfield County by Geoffery Thyne, Prepared for Garfield County, December 20, 2008
There is a temporal trend of increasing methane in groundwater samples over the last seven years that is coincident with the increased number of gas wells installed in the Mamm Creek Field. Pre-drilling values of methane in groundwater establish natural background was less than 1 ppm, except in cases of biogenic methane that is confined to pond and stream bottoms.