Ecological simulation and Lagrangian approach

А mathematical model and a numerical technique for the estimation of the damage to biological resources resulting from a pollutant discharge into aqueous environment are presented. With the use of the Lagrangian description of fluid motion a set of hydrophysical parameters is introduced on the basis of which hydrobiologists can estimate the damage. The computation of these parameters is illustrated by the example of a problem of a pollutant spreading in a canal. The problem is solved numerically on a deformable Lagrangian grid. To ensure computational stability a special grid reconstruction procedure with the subsequent interpolation of the parameters computed is used. An original interpolation technique which ensures the preservation of the most important hydrophysical quantities is proposed. Perturbances arising in the parameters computed as a result of the grid reconstruction procedure used are analyzed. These perturbances are shown to be insignificant.