Remote Infiltration Areas as a Main Source of Ground Water for Floodplain Forest Without Floods

Abstract

This article brings new information about phenomenon of the growth of floodplain forest without influence of floods over 50 years. Floodplain forest and its hydrogeological regime are under detail research for 10 years and detail 10 years data from hydrogeological well is used in this study. The area of interest belongs to nature reserve Plackuv les what together with brook Satava represents a unique relic of a floodplain forest in the confluence area of the rivers Svratka and Jihlava in southern Moravia (South‑Moravian Region). The damming of the channel of the river Svratka has caused the end of floods. Despite the anthropogenic regulations performed, the hydrogeological conditions have remained preserved at the site. Stream channel was rised due to the regulation at the above the level of the existing ground; this eliminated its drainage functions for groundwater. The contact between the base of floodplain loams and the groundwater Tab. is not lost and the capillary rise in them remains preserved. Analysis of groundwater level confirmed multi‑component refilling of the hydrogeological structure, which is drained in Plackuv les and the river Satava. All last 10 years, the maximum of the groundwater level measured is from July to September. It means, that groundwater reaches the highest level in the period, when the minimum flow rates are recorded on the surface flows. In this period, the locality displays the maximal infiltration of the precipitation from the last hydrological year from distant infiltration area. Because of the absence of floods, groundwater at this site is the most significant resource of water, and it represents a key‑factor which enables the growth and thriving of the floodplain forest ecosystem.