Krzysztof Książyński

This paper discusses the concept of an algorithm designed to determine actual evapotranspiration, taking into account the type of vegetation covering the land, the purpose the land is used for, and varying weather and soil conditions. Simple calculation methods are applied, taking into account individual factors which have been considered separately in the studies of soil conditions published to date.

A decrease in the flow of the downstream stretch of the Białucha river (also known as Prądnik) has been determined based on the calculations of groundwater inflow to the Białucha riverbed completed for the Ojców‒Giebułtów‒ Olsza stretch using the Wundt and Kille methods. Hydrogeological analysis of this phenomenon revealed that the water is lost at the point where the Prądnik leaves the Proszowice Plateau and enters the Vistula Plain as the Białucha. The reason for the water outflow from the riverbed is the relatively low groundwater level in the alluvia of the Vistula ice-marginal valley. Upstream from this point, groundwater is supplied to the river in a narrow valley eroded in rocky ground, while downstream water flows out into a thick aquifer drained by the Vistula river that is situated much lower in this area. A similar phenomenon is observed at the mouths of most tributaries of the upper Vistula. This problem is discussed in detail in the master’s thesis by Iwona Podraza [6].

The paper presents the calculation rules for infiltration into the saturated zone using a simplified piston model. It has been indicated that recharge is the same as during free infiltration for unsaturated infiltration and that a new system of boundary conditions has been proposed for saturated infiltration and redistribution of moisture. The volumes of infiltration calculated for those cases have also been compared with the results obtained in a simulation based on the conductivity equation, showing convergence.

The estimated characteristics of water seepage in a the vadose zone have been determined using analytical formulae based on the Carman-Kozeny capillary beam model. Only two standard soil parameters are needed to achieve this objective: hydraulic conductivity and porosity. The characteristics obtained find their application in a simplified description of infiltration known as the piston model.