Kazimierz Krzemień

Piping dynamics in mid-altitude mountains under a temperate climate: Bieszczady Mountains, eastern Carpathians: PIPING DYNAMICS: EROSION RATES AND PIPE ELONGATION

Abstract Piping has been recognized as an important geomorphic, soil erosion and hydrologic process. It seems that it is far more widespread than it has often been supposed. However, our knowledge about piping dynamics and its quantification currently relies on a limited number of data for mainly loess‐derived areas and marl badlands. Therefore, this research aimed to recognize piping dynamics in mid‐altitude mountains under a temperate climate, where piping occurs in Cambisols, not previously considered as piping‐prone soils. It has been expressed by the estimation of erosion rates due to piping and elongation of pipes in the Bereźnica Wyżna catchment in the Bieszczady Mountains, eastern Carpathians (305 ha, 188 collapsed pipes). The research was based on the monitoring of selected piping systems (1971–1974, 2013–2016). Changes in soil loss vary significantly between different years (up to 27.36 t ha−1 yr−1), as well as between the mean short‐term erosion rate (up to 13.10 t ha−1 yr−1), and the long‐term (45 years) mean of 1.34 t ha−1 yr−1. The elongation of pipes also differs, from no changes to 36 m during one year. The mean total soil loss is 48.8 t ha−1 in plots, whereas in the whole studied catchment it is 2.0 t ha−1. Hence, piping is both spatially and temporally dependent. The magnitude of piping in the study area is at least three orders of magnitude higher than surface erosion rates (i.e. sheet and rill erosion) under similar land use (grasslands), and it is comparable to the magnitude of surface soil erosion on arable lands. It means that piping constitutes a significant environmental problem and, wherever it occurs, it is an important, or even the main, sediment source. Copyright

Channel Changes due to Extreme Rainfalls in the Polish Carpathians

This chapter describes a role of extreme rainfall events in the development and transformation of channels in the Polish Carpathians. An analysis was based on the example of four selected events, which occurred in different parts of Polish Carpathians (Western Tatra, Bieszczady, and Beskid Niski Mountains) during the period 2003–2010. The findings underline that changes of the largest extent follow short and heavy rainfalls. Furthermore, their geomorphic impacts are the most significant in small watersheds. The research showed that the largest transformations of mountain rivers occur in the main channel, while the floodplain is only locally altered. The regularities identified in the study areas are relevant for mountain river channels in forested terrains, where a large supply of woody debris, for example, stems and branches, is ensured.

Can beaver impact promote river renaturalization? : the example of the Raba River, southern Poland

The European beaver (Castor fiber) was reintroduced in the Polish Carpathians in the 1980s after a few centuries of absence. It gradually colonized suitable habitats in the Raba River valley and elsewhere. The question arises as to whether beaver activity can play a role in the local improvement of hydromorphological conditions and spontaneous renaturalization of the Raba River channel. Field surveys were performed in morphodynamically and structurally homogeneous reaches of the river. Traces of beaver activity were identified and used to estimate the studied beaver population. Local beaver impact on the studied river channel was also determined. The Raba channel is trained along about 80% of its length and considerably incised. Traces of beavers activity were found in 16 out of 31 river reaches, mainly in the upper and lower river course. The study showed that relatively flat channel gradient, small maximum bed-material grain size, and high channel sinuosity favour beaver presence. The largest number of beaver habitats was identified in river reaches strongly altered by man and characterized by a uniform channel structure. Beaver impact on channel structure varies depending on differences of the river channel features in upper and lower reaches of the Raba River channel. In upper reaches, the impact of beaver activity (mostly dams) is reflected in increased lateral erosion, while slower water current reduces the tendency for bed degradation. In lower reaches, beaver impact is mostly limited to bank fragmentation (slides and burrows). Lateral erosion, accumulation of material at the toe of riverbanks, and wood debris accumulation all produce a local impact on river channel width. These beaver-initiated processes mostly alter artificially homogenized river reaches. Beavers may actually play a substantial role in future renaturalization of both upper and lower reaches of the Raba River.

Precipitation as a factor triggering landslide activity in the Kamień massif (Beskid Niski Mts, Western Carpathians)

Abstract On the landslide slope in the Beskid Niski Mts (Western Carpathians) 48 silver firs were cored for dendrochronological samples. Tree-ring widths were measured for the upslope and downslope sides of each stem. Events of landslide activity were dated using the method of the eccentricity index. The tree-ring record of landsliding was compared with the occurrence of precipitation in the study area. The nature of the relation between precipitation and landsliding is complex. We have found a statistically significant correlation between landsliding and the number of days with 24-hour precipitation totals above 20 mm and high 3-, 5-, and 10-day precipitation totals during winter half-years. Thus landsliding in the Kamień massif is triggered mainly by high precipitation totals in the preceding winter period. No such relation was found for annual precipitation totals and different types of precipitation totals in the summer period. Single landsliding events related to high summer precipitation totals were found, but the correlation is not statistically significant. In addition some landsliding events are 1–2 years lagged after the occurrence of high long-term precipitation totals. It seems that the strongest landsliding events resulted from sequences of wet summer, wet winter and once again wet summer seasons directly following one another.

Effects of environmental changes and human impact on the functioning of mountain river channels, Carpathians, southern Poland

Abstract In the northern slope of the Carpathian Mountains and in their foreland, river and stream channels have been significantly transformed by human impact. These transformations result from changing land use in river basins and direct interference with river channels (alluvia extraction, engineering infrastructure, channel straightening). Anthropogenic impacts cause significant changes in the channel system patterns leading to increased impact of erosion. This mainly leads to the channelling of the fluvial system. This article reviews studies of structure and dynamics of Carpathian river channels conducted based on the methodology of collection of data on channel systems, developed in the Department of Geomorphology of the Institute of Geography and Spatial Management, Jagiellonian University.

Natural conditions of coarse bedload transport in headwater catchments (Western Tatras, Poland)

ABSTRACT The aim of the study was to examine the magnitude and frequency of bedload transport in 1st–3rd order headwater catchments (with an area <2 km2) in the Western Tatras. The study was carried out in 19 headwater catchments, divided into two groups: (1) alpine catchments, and (2) montane catchments. Bedload transport measurements were carried out at intervals over a period of 40 years using the painted stone method. During large floods observed in the main stream (Q > 5 m3 s−1), usually associated with prolonged rainfall or a combination of both snowmelt and rainfall, it can be expected that bedload will also be activated in its tributaries and headwater sections. Bedload transport may also occur during snowmelts, but this type of flood is of a completely local nature. During small local floods, the role of the local channel structure is quite important. Channel topography can slow down transported bedload, which is particularly visible within alluvial fans. During high-energy events, this effect disappears, and the distance of bedload transport increases downstream. In alpine channels, bedload transport occurs on a much smaller scale than is the case in montane channels and it occurs along the entire channel length. The distance of bedload transport, its size, and the frequency of occurrence of geomorphologically-active floods are smaller in alpine catchments than in montane ones. In alpine channels, the maximum distance of bedload transport was 18.2 m, and in montane channels, distances reached 165 m.