Comment on 'Plume spreading in groundwater by stretching and folding' by D. C. Mays and R. M. Neupauer

The recent paper of Mays and Neupauer [2012] presents one such novel methodology for the acceleration of plume spreading with punctuated injection protocols that result in fluid stretching and folding which are the hallmarks of chaotic dynamics in continuous systems. This protocol shows excellent promise as a means to accelerate dispersion for groundwater remediation, recovery, and so on. Our comment regarding this paper does not directly pertain to this method but rather corrects an erroneous statement that has important implications for a wide class of intervention methods which involve 'recycled' injection, whereby extracted fluid is reinjected elsewhere in the subsurface to impart continuous fluid flow and deformation.