Field investigation of the drift shadow

Su, G.W. and Kneafsey, T. J. and Ghezzehei, T. A. and Marshall, B. and Cook, P.J.

Proceedings of the 11th International High Level Radioactive Waste Management Conference, IHLRWM , 2006.


The ”Drift Shadow” is defined as the relatively drier region that forms below subsurface cavities or drifts in unsaturated rock. Its existence has been predicted through analytical and numerical models of unsaturated flow. However, these theoretical predictions have not been demonstrated empirically to date. In this project they plan to test the drift shadow concept through field investigations and compare our observations to simulations. Based on modeling studies they have an identified suitable site to perform the study at an inactive mine in a sandstone formation. Pretest modeling studies and preliminary characterization of the site are being used to develop the field scale tests.