Black alder (Alnus glutinosa (L.) Gaertner) and its bank-protective effect on the banks of water flows quantified by method BSTEM

Abstract

The present article reviews the significance of Black alder (Alnus glutinosa (L.) Gaertner) in the
riparian stands of torrent Hučava (Protected Landscape Area Poľana) in connection with bank
stability of water flows and resistance of the banks of the bed against the erosion. Riparian stands
are nature nearest reinforcement of the banks of water flows with accent of nature and landscape
protection and biodiversity. Riparian vegetation increases the bank stability and erosion resistance
of the banks of water flows. In the geomorphological unit Poľana (Central Slovakia) were
investigated and compared 22 of experimental sections and profiles of torrent Hučava. On these
experimental sections was analyzed the stability and erosion resistance of the banks on the both
sides of the bed in connection with different density of stems of Black alder. The factor of stability
Fs of the banks of water flow was calculated according to Bank Stability and Toe Erosion Model
(BSTEM). The results indicated close correlation between the density of the stems of Black alder
and factor of stabilty Fs (correlation coefficient is I yx = 0.964 for the right banks and I yx = 0.952
for the left banks). The calculated results of Fs are in accordance with existing erosion damages
of the banks which were determined in terrain. The analysis confirms the influence of alder stands
to stability and erosion resistance of the banks of water flows. The results were validated by
statistical testing.