BBAuthors: Forde, O.N. .; Advisor: -; Participants: Mayer, K.U.; Cahill, A.G; Mayer, B.; Cherry, J.A.; Parker, B.L. (2018)
This paper presents results from vadose zone gas and surface efflux monitoring during a natural gas release experiment at Canadian Forces Base Borden, Alliston, Ontario, Canada. Over 72 d, 51 m3 of natural gas (>93% CH4) was injected into a shallow, unconfined sand aquifer at depths of 4.5 and 9 m. Methane and CO2 effluxes in combination with soil gas concentrations and stable C isotopic signatures were used to quantify the spatiotemporal migration and fate of injected gas. Preferential gas migration pathways led to vadose zone hot spots, with CH4 concentrations exceeding the lower explosive limit (5% v/v). From these hot spots, episodic surface CH4 effluxes (temporally exceeding 2500... 
