Ryszard J. Kaczka

Floods at the northern foothills of the Tatra Mountains — A Polish-Swiss research project

The present paper introduces the topical area of the Polish-Swiss research project FLORIST (Flood risk on the northern foothills of the Tatra Mountains), informs on its objectives, and reports on initial results. The Tatra Mountains are the area of the highest precipitation in Poland and largely contribute to flood generation. The project is focused around four competence clusters: observation-based climatology, model-based climate change projections and impact assessment, dendrogeomorphology, and impact of large wood debris on fluvial processes. The knowledge generated in the FLORIST project is likely to have impact on understanding and interpretation of flood risk on the northern foothills of the Tatra Mountains, in the past, present, and future. It can help solving important practical problems related to flood risk reduction strategies and flood preparedness.

Flash floods in the Tatra Mountain streams: Frequency and triggers

Flash floods represent a frequently recurring natural phenomenon in the Tatra Mountains. On the northern slopes of the mountain chain, located in Poland, ongoing and expected future changes in climate are thought to further increase the adverse impacts of flash floods. Despite the repeat occurrence of major floods in the densely populated foothills of the Polish Tatras, the headwaters have been characterized by a surprising lack of data, such that any analysis of process variability or hydrometeorological triggers has been largely hampered so far. In this study, dendrogeomorphic techniques have been employed in four poorly-gauged torrential streams of the northern slope of the Tatra Mountains to reconstruct temporal and spatial patterns of past events. Using more than 1100 increment cores of trees injured by past flash floods, we reconstruct 47 events covering the last 148 years and discuss synoptic situations leading to the triggering of flash floods with the existing meteorological and flow gauge data. Tree-ring analyses have allowed highlighting the seasonality of events, providing new insights about potential hydrometeorological triggers as well as a differentiating flash flood activity between catchments. Results of this study could be useful to design future strategies to deal with flash flood risks at the foothills of the Polish Tatras and in the Vistula River catchment.

Growth trends and climate responses of Norway spruce along elevational gradients in East-Central Europe

Key messageDecadal growth variability of Norway spruce increases with elevation. Recent temperature sensitivity and growth enhancement are limited to trees growing in the zone adjacent to timberline.AbstractGrowth trends and climate responses of forest trees along elevational gradients are not fully understood. A deeper insight is, however, fundamental for predicting ecosystem functioning and productivity under future climate change. Supplementary to the effects of elevation and regional provenance on tree growth are sample depth, uneven representation of sample age and varying site conditions. Furthermore, there is only a limited number of studies addressing growth changes along elevational gradients, while at the same time applying tree-ring standardization methods that are sensitive to trend preservation. Here, we introduce 12 novel tree-ring width chronologies of Norway spruce (Picea abies[L.] Karst.) from four elevational belts encompassing montane forests and the local timberline in three regions in East-Central Europe between 15° and 19°E. Each chronology is characterized by sufficient sample replication and a comparable age structure between 1906 and 2010. Tree growth near timberline revealed substantial medium-frequency variability and sharply increasing ring widths since the 1980s. Medium-frequency growth variability of lower elevation trees was, however, relatively small, and growth rates over the last decade were either stable or even decreased. During the last four decades, Norway spruce from higher elevations exhibited a reduced response to autumn temperatures preceding ring formation. In contrast, trees from the lower-montane zone increased their sensitivity to drought during the same time. Our results emphasize not only different but also instable growth trends and climate responses of forest trees along altitudinal gradients, which should be considered in future forest management strategies.

High-Precision Dating of Debris-Flow Events Within the Growing Season

We established and tested a new method of precise debris-flow dating using an existing model of wood formation (Deslauriers et al. 2003). The study was based on the hypothesis that scars and other wood anomalies record the stage of tree-ring development at the moment when a high-energetic impact kills the cambium, stopping further cell production. We also assumed that tangential rows of traumatic resin ducts and wood density fluctuations within the growth ring could develop soon after injury. Debris-flow sampling was carried out at four different sites located in three valleys of the Monts-Valin, north of the Saguenay River (48°40¢–49°00¢ N, 70°00’–71°15¢ E), Quebec (Canada). Fifty balsam fir (Abies balsamea) trees with scars dating back to 1996 were selected from a collection of 240 discs representing 12 debris-flows sites (Kaczka and Morin 2006). Major debris-flow events were recorded in the Saguenay region in 1996 as a result of severe rainstorms lasting from July 18–21 (199–202 Julian days). That known event was used to estimate the synchronism of three different proxies used in dendrogeomorphology to date debris-flow incidences, namely: (i) scars, (ii) tangential rows of traumatic resin ducts and (iii) density fluctuations.

Methods to Assess Large Wood Dynamics and the Associated Flood Hazard in Polish Carpathian Watercourses of Different Size

Applicability, advantages and limitations of a range of methods applied to determine large wood dynamics in Kamienica Stream and the Czarny Dunajec River, Polish Carpathians, are discussed. Results of a 6-year-long monitoring suggest an increased rate of wood recruitment to Kamienica Stream caused by recent bark beetle infestation of the spruce forests in the valley. However, both monitoring of wood transport and wood inventories indicate that the mobility of large wood in the stream is low and can increase only during major floods. Thus flood hazard to downstream valley reaches potentially resulting from the considerable amounts of large wood stored in the upper stream reach is limited. In the Czarny Dunajec, wood inventories, a tracking experiment with logs tagged with radio transmitters, and numerical modelling indicated high potential for wood transport in the narrow river reaches formed by channelization or channel incision, and high potential for wood deposition in the wide, multi-thread channel. Vegetative regeneration of living willow wood considerably reduces its remobilization by subsequent floods. Efficient transport of large wood along narrow river reaches implicates that during floods substantial amounts of wood may be delivered from distant sources to the channel sections located downstream of the narrow reaches. Wide, multi-thread reaches operate as natural wood traps, considerably limiting further transfer of wood to vulnerable sites/reaches.

The New Features of Landslide Relief Discovered Using Lidar – Case Study from Babia Góra Massif, Western Carpathian Mountains

Abstract Basing on LiDAR data, the re-interpretation of the limit and distribution of the selected landslide forms in 9 test areas were carried out. The forms are located at the slopes of the monoclinal ridge of Babia Góra Mt. (1,725 m a.s.l.) in the flysch Western Carpathians. The earlier knowledge on these landforms is shown in the unpublished map at the scale of 1:5,000 which was prepared basing on geomorphological mapping. Basing on the newest information source, subtle geomorphic signatures of landslides were found, the dynamics of these forms and directions of their further development were determined. Local differentiation of deep-seated landslides was indicated according to the relation between the sandstone layer dip and slope inclination, slope length, and altitude of the location of headwaters. An attention was paid to polycyclic relief of the highest located landslide forms, which contain the elements of glacial and nival morphology, and some are modelled by debris flows.

Changes of flood risk on the northern foothills of the Tatra Mountains

The present paper reviews selected outcomes of the FLORIST project devoted to flood risk in the region of the northern foothills of the Tatra Mountains in Poland and summarizes novel results. The project encompassed theoretical, field, and modeling work. It was focused around observation-based hydroclimatology; projections for the future; dendrogeomorphology; as well as influence of transport of large wood on fluvial processes. The project improved understanding and interpreting changes in high-flow frequency and magnitude as well as changes in flood risk in the region, related to the presence of large wood in mountain streams. A unique database on past episodes of intense precipitation and flooding was created, harnessing multiple sources. The project showed that the analysis of tree rings and wood logs can offer useful information, complementing and considerably enriching the knowledge of river floods in the region of northern foothills of the Tatra Mountains. Retrospective and scenario-defined modeling of selected past fluvial events in the region was also performed.

Climate Reconstruction from Tree-Rings in the Tatra Mountains

This chapter examines the long-term variability of summer (June–July) air temperature and summer humidity (precipitation and Standardised Precipitation Evapotranspiration Index, SPEI) in the region of the Tatra Mountains, which represents natural climate conditions, free of strong anthropogenic influences. The reconstruction of temperature is available for the period since the beginning of the 17th century and reconstruction of humidity related parameters since the beginning of the 18th century by means of the methods based on the tree-ring chronologies. The main proxies utilized for temperature reconstruction were tree-ring widths of Norway spruce (Picea abies (L.) H. Karst) and Stone pine (Pinus cembra L.) growing in the timberline ecotone. The precipitation and SPEI were reconstructed based on Scots pine (Pinus sylvestris L.) tree-ring widths of trees growing at ~1000 m a.s.l. The reconstruction of summer temperature from tree-rings pointed to a relatively cold interval as a part of the Little Ice Age (from the mid 16th to late 19th centuries). In the 20th and at the beginning of the 21st centuries, general increase of air temperature was observed. However, in this recent warm period and during earlier main climatic periods, temperature conditions were not uniform. Analysing series of summer temperature (the 17th–21st centuries) several shorter warm and cool fluctuations were observed. The reconstructed humidity variables exhibited less variability. This is the first attempt of precipitation reconstruction in mountains regions based on the tree-ring chronologies. But the correlation between flood events and humid periods is poor due to the predominant character of the flood caused by short term intensive precipitation of short duration.

Deciphering Flood Event Information from Tree-Ring Data in the Tatra Mountains: Implications for Hazard Assessment

Mountains and their foothills are areas where intense floods are characterized by high discharge and where they occur more often than in lowlands. Furthermore, due to the fact that they are mainly caused by short-lasting heavy rainfall events, they are difficult to predict. The dense network of meteorological stations and river gauges is crucial to understand hydrological processes and to forecast floods. Most mountain regions suffer from a scarcity of instrumental data that are long enough for scientific purposes. In such cases where historical data or instrumental records are lacking, floods in forested catchments can be analysed by using growth series from trees growing along stream channels. In the streams draining the northern slopes of the Tatra Mountains, it was possible to reconstruct the occurrence and magnitude of paleofloods using tree-ring data. More than 1100 increment cores were sampled from 218 Picea abies and Abies alba trees growing at 6 stream sectors and allowed determination of 480 growth disturbances and a definition of the magnitude of 47 flood events between A.D. 1866 and 2012. In this region, floods are triggered by intense and prolonged rainfall events in spring and summer. These paleoflood records also allowed construction of a regional flood analysis and to reduce the uncertainties in the flood frequency assessment.

Development of Tourist Infrastructure on Babia Góra Mt. (Western Carpathians) in Conditions where There is Risk Due to Slope Processes

The aim of the paper is to evaluate the sustainability of the location of all elements of tourist infrastructure on the slopes of Babia Gora Mt. in the Western Beskidy Mountains taking into account local relief and a range of geomorphologic processes. For more than 130 years, local tourist facilities remained unthreatened by slope processes with the exception of very limited sections of the northern slope. A deep-seated landslide reactivated in the mid 19th century affected a small section of that slope that is outside of regular tourist traffic while another landslide, a shallow one that remains active, has been damaging a single marked tourist trail. Debris flows observed locally on the northern slope are not typical of contemporary relief dynamics across Babia Gora Mt. and therefore cannot be regarded as a universal threat to local tourist infrastructure. In addition, snow avalanches that reach short stretches of tourist trails on the northern slope have not damaged them. The current hazard status of the tourist infrastructure on Babia Gora Mt. is clearly better than it would have been if certain heavy development plans had been carried out in geomorphologically vulnerable areas.