Assessing the transport and fate of MTBE amended petroleum hydrocarbons in the UK Chalk aquifer

solinst petroeum fuel formulations downhole geophysical fracture logging verticle hydraulic profiling multilevel sampling verticle solute profiles distribution of contaminants image

G P Wealthall, S F Thornton and D N Lerner
Groundwater Protection and Restoration Group,
University of Sheffield, UK




The vertical hydraulic head gradient in the upper 20-25 metres of the saturated Chalk aquifer at the site is insignificant. Below this depth the head profile observed in the upgradient well (MW14), is negative relative to the open borehole, indicating outflow in the open borehole. This observation correlates with the inferred location of a hardground at a depth of ca. 45 metres below forecourt level (mbfl) in MW14

The horizontal groundwater gradient ranges from 0.0016-0.0031 (m/m)

The local ground water flow direction also varies temporally between 150-160° (SSE) and is sub-parallel to the regional groundwater flow direction of around 140° (SSE-SE)

The water table elevation fluctuates temporally by ca. 2 m