Repozytorium publikacji - Politechnika Gdańska

Ustawienia strony

english
Repozytorium publikacji
Politechniki Gdańskiej

Treść strony

Deterministic versus stochastic modelling of unsaturated flow in a sandy field soil based on dual tracer breakthrough data

The 216 km2 Neuenhagen Millcreeck catchment can be characterized as a drought sensitive landscape in NE Germany. It is therefore a fundamental human interest to understand how water that fell as precipitation moves through the unsaturated soils and recharges groundwater. Additionally, a better knowledge of nutrient transport from soil to groundwater is important also, especially in landscapes with light sandy soils. For a better understanding of these processes a dual tracer field experiment with bromide (Br-) and deuterium (D2O) was carried out years ago. The aim of the present study is to use results of these data for modelling tracer transport in the unsaturated zone with two different concepts, the classical deterministic advection – dispersion equation and a new stochastic approach. The advantage of the stochastic modelling method proposed here for field scale tracer application is to produce reliable information about expected total solute fluxes from the unsaturated zone to groundwater or mean transit times. Moreover, this allows one to evaluate the mass of solute in the soil profile and to determine the range of water velocity fluctuations. Field experiments should be concentrated on estimation of fluctuation of water flow velocity to make stochastic models more accurate. To summarize, this work contributes to new modelling methods for simulation of water and solute transport in unsaturated sandy soils which are heavily affected by droughts and irregular hydrological processes in the subsurface.

Autorzy