=

calendar date representing the actual starting time of the activity of the sources;

=

calendar date representing the starting time of the simulation for any particular candidate solution in the optimization model;

=

time lag between the first measurement of concentration and a candidate starting time for the source;

=

calendar date representing the first concentration measurement obtained from the site;

=

time interval between concentration measurements;

=

number of concentration measurements available at a given observation location;

=

total number of concentration measurement wells;

=

time interval between the starting time of the simulation and the starting time of the activity of source;

=

seepage or linear pore water velocity;

=

volumetric flux of water per unit volume of aquifer representing sources;

=

concentration of the sources or sinks;

=

porosity of the porous medium;

=

chemical reaction term for each of the N species considered;

=

pollutant source fluxes;

=

absolute difference;

=

simulated concentration at observation location iob at time ts;

=

observed concentration measurement at observation location iob at time ta;

=

perturbed numerically simulated concentration value;

=

error term;

=

maximum deviation expressed as a percentage;

=

random fraction between −1 and +1;