THE MOMENTS OF THE BREAKTHROUGH CURVES OF INSTANTANEOUSLY AND KINETICALLY SORBING SOLUTES IN HETEROGENEOUS GEOLOGIC MEDIA - PREDICTION AND PARAMETER INFERENCE FROM FIELD-MEASUREMENTS

This paper presents a concise methodology for estimating the moments o f the breakthrough curves for tracers and reactive solutes in heteroge neous aquifers. Under some conditions these are also the temporal or t ravel time moments between a source and a given destination downstream . The temporal moments of tracers as well as instantaneously or kineti cally sorbing solutes, characterized by linear isotherms, are expresse d in terms of a few parameters which characterize the chemical reactio ns and the spatial distribution and correlation structure of the hydra ulic conductivity. The chemical reaction parameters are assumed to be homogeneous. The estimated moments can also be made conditional to fie ld measurements. Applications for the case of uniform mean flow are pr esented, but the general approach can be applied for other flow regime s such as injection-pumping well doublets. Physical and chemical noneq uilibrium processes are represented by mobile-immobile domains and two -site models, respectively. The estimated temporal moments can be used for both predictive purposes as well as for interpretation of field e xperiments. These mio objectives are pursued in this paper. A signific ant advantage of the solution is that it does not require the assumpti ons of Gaussianity or log Gaussianity of the travel times. Throughout the discussion the combined and relative effects of the mass transfer and kinetic parameters and the spatial variability of the conductivity on the travel time moments are evaluated.