|Title||Advective - dispersive contaminant transport towards a pumping well|
|Author(s)||Kooten, J.J.A. van|
|Source||Agricultural University. Promotor(en): J. Grasman; M. de Gee. - S.l. : Van Kooten - ISBN 9789054854722 - 120|
Mathematical and Statistical Methods - Biometris
|Publication type||Dissertation, internally prepared|
|Keyword(s)||milieu - grondwater - watervoerende lagen - computersimulatie - simulatie - simulatiemodellen - waterkwaliteit - verontreinigingsbeheersing - grondwaterverontreiniging - bescherming - grondwaterstroming - modellen - permeabiliteit - gesteenten - colloïden - dispersie - pompproeven - environment - groundwater - aquifers - computer simulation - simulation - simulation models - water quality - pollution control - groundwater pollution - protection - groundwater flow - models - permeability - rocks - colloids - dispersion - pumping tests|
|Categories||Information and Communication Technology (General)|
In this thesis we describe an analytical approximation method for predicting the advective- dispersive transport of a contaminant towards a pumping well. The groundwater flow is assumed to be stationary and essentially horizontal. Due to dispersion contaminant transport is a stochastic process. We derive approximations for the arrival probability (or fraction) of particles at a well, for the mean and variance of the arrival time and for the arrival time distribution at a well. The advective flow yields first order approximations. The effect of longitudinal dispersion is included by expanding the first and second moment of the arrival time in power series of the longitudinal dispersion coefficient. Transversal dispersion only plays a crucial role near the separating streamlines bounding the catchment area of a well. Its effect is analyzed locally with boundary layer techniques. The incorporation of linear equilibrium adsorption and first order decay is rather straightforward. The asymptotic approximations are compared with the results of random walk simulations.
A self-contained part of this thesis is devoted to the transport of a kinetically adsorbing contaminant. We show that once the transport of a non-adsorbing contaminant has been computed, the effect of first order kinetics can be incorporated naturally by utilizing a stochastic description of the residence time of particles in the free phase.
The results of our research have been implemented in the software package ECOWELL. The input of ECOWELL consists of a head field generated with a numerical flow model. The technical documentation of ECOWELL is part of this thesis. The use of ECOWELL is demonstrated in a case study.