Saprykin V. Unsaturated flow in the vadose zone and groundwater recharge at radioactive waste dump site in the zone of ChNPP

The thesis considers unsaturated flow processes in soils of vadose zone at “Red Forest” radioactive waste dump site in the Chernobyl exclusion zone. The subject of thesis is of particular interest as unsaturated flow is the main factor causing migration of radionuclides of the Chernobyl accidental release to groundwater. The study uses an experimental data set obtained in 2000-2012 at the field polygon of the Institute of Geological Sciences in the Chernobyl exclusion zone using automated monitoring systems. In the course of research presented in the thesis, methods were developed (or improved) for estimating of hydrophysical parameters of soils of the vadose zone, as well as methods for quantification of groundwater recharge, that are based on the analysis of automated monitoring data collected in situ. A computer model for unsaturated flow of the soils of vadose zone of the experimental site was developed and validated. The accomplished studies allowed to determine peculiarities of unsaturated flow in the soils of the radioactive waste dump site and to quantify groundwater recharge of the first from the surface unconfined aquifer in inter-relation with meteorological factors in seasonal and multi-annual dynamics.