Warta River Valley Research Articles

Palaeogeographical conditions of the functioning of the fossil channel in the Koźmin-Głowy site; Warta River valley, Koło Basin

Palaeogeographical conditions of the functioning of the fossil channel in the Koźmin-Głowy site; Warta River valley, Koło Basin

Morphological changes in the backwater of the Jeziorsko Reservoir against the background of changes in the bottom of the Warta River valley between the Widawka estuary and Uniejów town in the Anthropocene

Morphological changes in the backwater of the Jeziorsko Reservoir against the background of changes in the bottom of the Warta River valley between the Widawka estuary and Uniejów town in the Anthropocene

Giant hail in Poland produced by a supercell merger in extreme instability – A sign of a warming climate?

Severe thunderstorms that occurred on 11 June 2019 over eastern Germany and western Poland caused severe material losses primarily due to large hail. This work documents a detailed inventorization of 79 large hail reports collected in the densely populated area of Gorzów Wielkopolski in Poland, including the largest with a diameter of 12 cm and heaviest with a weight of 380 g. Evaluation of environmental and Doppler radar data indicate that three unique aspects characterize this event. Firstly, the storm benefited from a favorable convective environment including a record-high CAPE exceeding 4000 J kg−1 that was the highest ever measured value at a proximity rawinsonde station of Lindenberg, and the highest for this region according to ERA5 since 1950. Secondly, moisture pooling along the convergence zone led to convective initiation of 3 isolated cells that merged together. Two of them with already embedded rotation. This merger subsequently evolved into a single powerful mesocyclone that was a main cause of giant hail. Subtle differences in the orography within Warta river valley could have played a role in the merging process. Third, a supercell had the biggest intensity over a densely populated area, which led to considerable material losses, but also allowed collection of a large number of hail reports. Distribution of these reports indicates that peak hail size varied significantly on very small distances. Storm has been producing giant hail for around 20-min over a distance of around 10 km and was preceded by a well-developed velocity couplet, bounded weak echo region and hook-echo signatures on the Doppler radar scans.

Changes in habitat conditions in a Late Glacial fluviogenic lake in response to climatic fluctuations (Warta River valley, central Poland)

The Warta River valley was greatly influenced by the ice sheet of the Last Glacial Maximum (LGM). A small peatland located in the Warta drainage system is here used as a palaeoarchive of climatic and habitat changes during the Late Glacial (Weichselian). The Ługi sediment profile was investigated using multi-proxy (pollen, Chironomidae, Cladocera and geochemistry) analyses that recorded changes in a fluviogenic sedimentary depression. After the Poznań Phase (LGM), Ługi functioned as an oxbow lake that was cut off from the active river channel as a result of fluvial erosion. Since that time, the Warta River has flowed only along the section now occupied by the Jeziorsko Reservoir. Sedimentation of lacustrine deposits started at the beginning of the Late Glacial. Summer temperature reconstructions indicate cool Oldest and Younger Dryas, but no clear cooling in the Older Dryas. During the Younger Dryas the palaeolake was completely occupied by a peatland (fen), which periodically dried out during the Holocene. Investigation of this site has tracked the reaction of the habitat to climatic, hydrological and geomorphological changes throughout the Late Weichselian.

Wpływ powodzi z 2010 roku na morfologię południowej części dna Zbiornika Jeziorsko

Issues related to the transport of fluvial debris and deposition of alluvia in reservoirs have been the subject of intense research in many centres around the world for about a century. Studies of the silting rate of dammed reservoirs and the sedimentological characteristics of the deposited material are important from the point of view of the service life of these reservoirs. A reduction in capacity of 80% or even, according to many scholars, of 50% reduces the capacity of reservoirs to fulfil various important functions for which they are designed. In the case of the Jeziorsko Reservoir (central Poland), the problem of sediment accumulation was investigated by Wicher- -Dysarz and Dysarz (2016) after 30 years of its existence. The scholars applied several research procedures, adopting geodesic profiling as the main method. The data they obtained varied depending on the applied method, which indicates significant differences in their precision. For this reason, new methods must be sought. This article attempts to determine geomorphological and sedimentological changes in the southern part of the Jeziorsko Reservoir that occurred in the years 2009–20011 mainly as a result of the flood in the Warta River valley in May and June 2010. The flood was one of the largest in this valley in the last century. The main source of data was LiDAR measurements carried out in the years 2009 and 2011, i.e. one year before and one year after the catastrophic flood. Certain spatial data were visualised, including the extent of depositional processes, volume and distribution of sediment thickness, altered shapes of relief forms in the upper part of the reservoir, as well as other related environmental changes. Aerial and satellite photography taken throughout the reservoir’s existence and archival cartographic, geological, hydrological and botanical data were used for this purpose. It was found that the results of the flood included partial filling of channels within the delta, the disregulation of the outline of previously originated relief forms, and the formation of hundreds of fine hills of between several and twenty metres in diameter and rarely exceeding 1 metre in height. The thickness of the sediments deposited as a result of the flood in the vast majority of the area is 0.5–0.7 m, with the occurrence of small areas of slight depressions. The extent of flood-related debris accumulation was found to be linked with the most elevated, middle and northern part of the delta, particularly in the zone of tall vegetation. The authors also conducted a discussion of the previous research results from other authors, mainly in the context of silting of the reservoir. The effectiveness of sediment deposition as a result of the flood was primarily influenced by the following: existing depressions in the form of channels, existing narrowings or broadenings of the flood water flow zone (constrained flow, free flow), and concentrations of vegetation – especially tall (riparian and scrub) vegetation. It was found that, although lidar data are more precise than those obtained using other methods, one must take into account the possibility of errors that are difficult to estimate. This applies mainly to water-covered areas and, to a lesser extent, to accumulations of small convex forms. Due to this, part of he area was excluded from further analyses. Measurement using the trapezoidal rule in Golden Software Surfer 16 revealed 667 986 m3 of deposited material. This means that the overall cubic capacity of debris deposited during the 2010 flood may exceed the entire accumulation to date. For this reason, siltation analyses should account for the possible occurrence of catastrophic events, especially floods.

Parki w Uniejowie i Turku ostojami rodzimej flory leśnej w rolniczym krajobrazie środkowej Polski

Badaniami objęto florę roślin naczyniowych parku zamkowego w Uniejowie i parku miejskiego im. Żerminy Składkowskiej w Turku. Pierwszy z ogrodów został założony w dolinie Warty, drugi w dolinie niewielkiego cieku o nazwie Folusz. W sezonach wegetacyjnych 2018–2019 przeprowadzono spisy roślin naczyniowych w obu obiektach. Wśród odnotowanych gatunków wydzielono grupy: socjologiczno-ekologiczne, siedliskowe oraz geograficzno-historyczne. Bazując na analizie flory w zakresie spektrum geograficzno-historycznego określono dla badanych obiektów wybrane wskaźniki antropogenicznych zmian. W charakteryzowanych obiektach odnotowano łącznie 314 gatunków roślin naczyniowych. Flora parku zamkowego w Uniejowie obejmuje 217 gatunków, a w parku miejskim im. Żerminy Składkowskiej stwierdzono 202 taksony roślin naczyniowych. We florach badanych ogrodów odnotowano 217 gatunków rodzimych i 97 obcego pochodzenia. Parki są siedliskiem dla takich gatunków jak: Gagea pratensis, Thalictrum flavum, Galium schultesi oraz Corydalis intermedia. Szatę roślinną założenia ogrodowego w Uniejowie charakteryzuje wyższy wskaźnik naturalności flory (25%), niż flory parku w Turku (10,9%). Rezultatem tego są wyższe wskaźniki obrazujące antropogeniczne przemiany obiektu leżącego w Turku. Parki wokół zabytkowych obiektów (zamków, pałaców, dworów) oraz duże parki miejskie stanowią refugia flory naturalnych siedlisk w krajobrazie antropogenicznym.

Roman Period well fills resulting from using and abandonment in environment of a river valley (Kwiatków site, Central Poland)

The research was conducted at the Kwiatków site,1 in the Koło Basin (Central Poland). It included a fragment of a low terrace and the valley floor of the Warta river valley. The archaeological investigation documented over 100 wells that archaeological material indicates are associated with the Przeworsk culture. Geomorphological, lithological and geochemical studies were carried out at the archaeological sites and their surroundings. Selected for the presentation were two wells whose fillings were carefully tested and subjected to geochemical and lithological analyses. The wells showed a slightly different content of artifacts, as well as differences in their grain-size distributions, the structure of their filling deposits, and their geochemistry. This allows us to conclude that the two wells were used differently, but also probably about a different course for how each well was filled after the end of its operation.

Environmental conditions as a key factor in the functioning of wells at a settlement from the Roman period of the Iron Age

The article deals with geological and geomorphological conditions of the construction and functioning of wells from the Roman period of the Iron Age in a settlement on the Amber Road. This settlement is located in Central Poland (in the vicinity of Kwiatków village), on a flat surface of the lower terrace of the Warta River valley, among the dry channels of numerous streams cutting the terrace, which developed in three generations, from the Younger Dryas onwards. In the Holocene, the area was characterised by an abundance of flowing water in a multichannel system and the stability of the groundwater table. Among the archaeological features discovered there, the most interesting is a large complex of well-preserved wells dated to the early Roman period. The structures of the wells were based or dug in an organic series which constituted the terrace profile at a depth of between 2.0 and 2.5 m, dated to the late Alleröd and the Younger Dryas. In the study, the authors focus on the purpose of locating a large number of wells within a relatively small area abundant with numerous streams. The authors used a range of methods, including lithological and textural analyses, a geochronological analysis and a geochemical examination to describe the properties of the deposits and the quality of the waters. The characteristics of the wells were provided from dendrochronological studies. The archaeological approach included an analysis of the features morphology and the stage of technological advancement, as well as the diversity of the wells’ casings. The spatial and functional relationships of the locations of the wells were also given special attention.

Existing and Proposed Urban Geosites Values Resulting from Geodiversity of Poznań City

Abstract Poznań, a city in central-western Poland, is located in the lowland region but has no less attractive geomorphological and human history. It was here that Poland was born at the end of the tenth century. The city’s location is connected with the meridian course of the Warta River valley. In contrast, in the northern part of the city, there is a vast area of the frontal moraines of the Poznań Phase of the Weichselian Glaciation. Against the backdrop of the geomorphological development of the city, the article presents the existing geosites, classified as urban geosites. The present geosites include three lapidaries with Scandinavian postglacial erratics, one of them also with stoneware, a fragment of a frontal push moraine and impact craters. Besides, three locations of proposed geosites with rich geomorphological and/or human history were identified. These are as follows: the peat bog located in the northern part of the city, defence ramparts as exhumed anthropogenic forms, and the Warta River valley. The existing and proposed geosites in Poznań were evaluated in three ways. In general, it should be assumed that the proposed new geosites are higher ranked than the current ones.

Palaeoenvironmental Proxies for Permafrost Presence During the Younger Dryas, Central Poland

AbstractInvolutions and small frost fissures have been recorded over a wide area of the lower terrace of the Warta River valley (central Poland). They developed at the lithological boundary between an organic‐rich deposit with a thin peat layer (unit b) and an underlying fluvial sandy deposit (unit a). Most of the involutions are products of a reversed density gradient and loading, or developed under the influence of cryohydrostatic pressure. Among them are drop‐like and flat‐bottomed structures, diapirs, flame‐like and fold structures and irregular involutions. Some frost fissures have also been recorded in the same stratigraphic position. The sedimentological properties and formative mechanism of the involutions, together with environmental data (lithology, groundwater conditions, snow cover and vegetation), reveal their origin as periglacial. Radiocarbon dating indicates that the structures formed during the Younger Dryas. Overall, the involutions and frost fissures indicate that permafrost re‐aggraded in this region of central Poland during the Younger Dryas. Copyright © 2017 John Wiley & Sons, Ltd.

Population structure of Liparis loeselii (L.) Rich. in relation to habitat conditions in the Warta River valley (Poland)

Abstract The paper presents results of a study on the population structure of the orchid Liparis loeselii growing in the Warta River valley peat bog in Myszków (Woźnicko-Wieluńska Upland, S. Poland). Individuals of L. loeselii occurred in patches of Menyantho trifoliatae-Sphagnetum teretis and Eleocharitetum pauciflorae – associations. The demographic structure of L. loeselii populations was described by variations in plant height, the length and width of leaves and the number of flowers of the constituting individuals. It was observed that habitat conditions such as conductivity, pH and the percentage cover of tall perennials had the strongest effect on the structure of L. loeselii populations.

Analysis of Prognosis of Lowland River Bed Erosion Based on Geotechnical Parameters

Abstract The river erosion is a complex process, the dynamics of which is very difficult to predict. Its intensity largely depends on hydraulic conditions of the river channel. However, it is also thought that natural resistance of the subsoil has a great influence on the scale of the erosion process. Predicting the effects of this process is extremely important in the case of constructing a piling structure (for example, artificial reservoirs). The partition of the river channel causes significant lowering of the river channel bed downstream the dam which threatens the stability of hydro technical and engineering (bridges) buildings. To stop this unwanted phenomenon, stabilizing thresholds are built. However, random location of thresholds significantly reduces their effectiveness. Therefore, taking under consideration natural geotechnical conditions of the subsoil appears to be extremely important. In the light of the current development of in-situ tests in geotechnics, an attempt to use results from these tests to predict the bed erosion rate was made. The analysis includes results from CPTU and DPL tests, which were carried out in the Warta River valley downstream the Jeziorsko reservoir. In the paper, the general diagrams for the procedure of obtaining and processing the data are shown. As a result, the author presents two multidimensional bed erosion rate models built based on hydraulic data and results from CPTU or DPL tests. These models allow taking more effective actions, leading to the neutralization of the effects of the intensive bed erosion process.

Younger Dryas flood events: A case study from the middle Warta River valley (Central Poland)

The Weichselian Late Glacial sequence composed of Younger Dryas overbank deposits and the Alleröd/Younger Dryas organic-rich series from the Warta River valley, Central Poland, were studied within a project, including sedimentological criteria, analysis of aquatic invertebrates (cladocerans and chironomids) remains and diatoms. The well-dated sequence of events on the floodplain, mainly due to the determination of the age of in situ riparian forest, provided a basis for a reconstruction of local conditions of palaeofloods in a wide context of global climatic changes at the Weichselian decline. The flash floods were largely affected by catchment topography, forest destruction in response to the Younger Dryas cooling, and permafrost reappearance. The floods have been detected as the causative factors in a river style change.

Inquiry of levee formation by grain size analysis — A case study from the Warta River (central Poland)

Levees were the most easily recognised depositional forms developed after two subsequent floods that occurred in summer 2010 and winter 2010/2011 in the Warta River valley (central Poland). The levees are built of mainly by fine-grained, well-sorted, massive or climbing ripple-laminated sands. The forms were sampled in 3 pits, 0.75–1.1m deep. Samples were collected every 5cm in vertical profiles. The main aim of the study was to investigate changes in the grain size of the sands deposited during one flood episode. Analyses indicated slight differences in the grain-size of the deposits, with a mean ranging from 1.9 to 2.5phi. However, a detailed grain-size analysis of sand samples showed that a single flood event was represented by a coarsening-upward sequence. It is generally assumed that such a trend indicates an increasing energy of the transporting medium. Therefore, the deposits recorded the rising flood stage. In scatter plots of mean vs. skewness and mean vs. kurtosis, the examined deposits show a V-shaped point arrangement. It may indicate the mixing of grain subpopulations. Differences in flow energy, observed mainly within the channel banks, resulted in mixing sediment transported in saltation with sediment transported in graded suspension.The paper proposes a model sequence for levee deposition during flood event. It is directly related to the flood progress: 1) beginning of the flood — fine-grained sand, 2) rapid rise of water level (up to the inflection point) — inverse grading deposits, and 3) slow rise and stabilisation of the water level (up to the culmination point) — fining upward deposits. The subsequent phase of falling water level does not involve deposition. Therefore, a single flood (particularly the rising phase) is represented by a pensymmetric sequence. However the uppermost part of the sequence is sometimes lacking in the fossil record which results in an upward coarsening sequence.

Archiwum zmian środowiska naturalnego okresu przełomu plejstocen-holocen w basenie uniejowskim

Archives of changes in the natural environments are gathered in various kinds of sediments,depending on the time in the history of the Earth. The Quaternary environmental variations are recorded from the ocean cores and the Greenland or Antarctic ice cores. High temporal resolution for shorter periods may be derived from annually laminated lacustrine sediments. A versatile archive for palaeogeographical reconstruction of the time of the Pleistocene–Holocene transition in the fluvial has been found at Koźmin Las site in the Uniwejów Basin of the middle Warta river valley. Well-preserved remains of pine subfossil forest as trunks and in situ stumps and accompanying organic deposits, of the late Alleröd and Younger Dryas age, have been subjected to multiproxy palaeoecological analysis and geological investigations. The sediments stored signals of a few short terrestrial events intrrupted by periodic floods. It has been concluded that the forest was destroyed by deteriorating hydrological conditions or a sudden catastrophic event, like a strong wind, in response to a global climatic change of the Pleistocene–Holocene transition. The Late Weichselian natural events recorded at the site point to a possible reaction of the fluvial system in a changing climate and environment. The knowledge about the past is essential to the creation of current ecosystem management strategies.

Palaeogeographical significance of the Eemian biogenic sediments at the Bór site (Warta River valley, central Poland)

An investigated area is located in the middle reach of the WartaRiver valley. During drillings in the Bór site organic deposits such as detritous calcareous gyttja and calcareous detritous gyttja has been documented in a depth between 14,9 and 16,6 m. The organic deposits are covered by mineral, mostly sandy deposits. The accumulation took place in the small lake formed as an abandoned channel. Palynological analysis led to conclusion that biogenic accumulation began at the end of Wartanian and took place at least to the Eemian Interglacial optimum. Results of palynological, Cladocera and geochemical analysis inform about water level changes and increasing of trophy status of the reservoir. Presence of Mesozoic substratum very close to the palaeolake bottom influenced significantly chemical features of the organic deposits. As Eemian organic deposits are uncommon in the Warta River valley, the Bór site seems important for palaeogeographical reconstructions of the Warta River valley during Eemian Interglacial.             Normal 0 21 false false false PL X-NONE X-NONE

Environmental influence on forest development and decline in the Warta River valley (Central Poland) during the Late Weichselian

At Koźmin Las, in the Warta River basin, Central Poland, a series of well-preserved tree trunks and in situ stumps, accompanied by organic deposits, all of Alleröd/Younger Dryas age, have been the focus of a multiproxy palaeoecological study using pollen, plant macrofossil, Cladocera and Chironomidae based on absolute radiocarbon dating. This is the first study to use a dendrological approach to Late Weichselian palaeoenvironmental reconstructions in Central Poland. This study reveals a series of short terrestrial events interrupted by flood episodes in response to climate cooling and provides new opportunities for research into the economic adaptation of Late Palaeolithic hunters to changes in the local environment. Evidence from dendrological studies shows that the riparian forest consisted predominantly of pines of a maximum age of about 140 years and an average age of 68 years. A local pine chronology spanning 133 years has been constructed. The forest appears to have been destroyed ca. 12,600 cal BP by deteriorating hydrological conditions or a sudden catastrophic event (strong wind ?) related to climatic change.

Never ending story: a lesson in using sampling efficiency methods with ground beetles

Biological inventory is a crucial activity in life sciences field research. However, it is sometimes time-consuming and laborious to take representative samplings of communities, especially in the case of invertebrates. In this paper, we address the issue of sampling efficiency and its influence on obtained results. As a study system, we used data on epigeic carabid beetles (Carabidae) collected in 1999–2001 in the Warta River valley of western Poland. We trapped a total of 17,722 individuals belonging to 108 species. However, due to rarefaction methods, the expected number of species was estimated at 134–140, suggesting that from 26 to 32 species are missing from the material, even expressed as a huge number of collected specimens. The estimated probability that another captured individual will represent a new species (i.e. a species that was not already recorded) is 0.0010. In order to record all the species present in the study area, another 193,338 individuals need to be sampled (abundance-based approach) or another 1,871 samples need to be collected (incidence-based approach). This means that the collected material should be 10.9 times greater (or 7.9 times greater for incidence-based data) than what was actually collected in order to record all the species present in the study area. The results show that, in practice, full inventory is simply nearly impossible to achieve, and this knowledge should be included in inventory planning. Therefore, we argue that species accumulation curves and unseen species estimators need to be carefully examined and threshold probability of detecting a new species should be built into the design of inventory science. The ratio between recorded and estimated species richness and the estimated efficiency of further sampling can be easily computed with available freeware software and should be incorporated when performing biological inventories.

Geologic position of the Younger Dryas subfossil forest in the Warta River valley, central Poland

Geologic position of the Younger Dryas subfossil forest in the Warta River valley, central Poland

Impact of Land Use Changes and Dynamic Vegetation Changes on Vascular Flora Diversity in Małków–Bartochów (the Warta River Valley)

The paper presents the changes of vascular plant flora in the Małków–Bartochów peatland area (the Warta River valley) which took place over a 40-year period. Vanishing, permanent and new components of the flora are presented with a special focus on valuable (protected by the law, threatened and locally rare) species. Changes in the share of ecological groups are estimated and discussed. Anthropogenic and natural factors, directly or indirectly influencing (in the past and at present) flora composition, are noted and analyzed.