Geographia Polonica (2010) vol. 83, iss. 1

Abstract

Today’s fl ood events along the River Wieprza assume a quite characteristic course entailingcalm spillovers of water from the bed in places of riverbank lowering and in sections above andbelow bridges, where a narrowing of the channel is present. The identity of the land inundated relatesto morphology, the near-channel part of a fl oodplain may be affected or those parts in depressions thatserve as fl ood basins.Riverbank exposures on both sides of the present river channel plus pits reveal the construction of theWieprza fl oodplain. The sediments that build the fl oodplain represent channel and overbank facieswith subfacies of palaeomeander fi lls. Analysed exposures are located along the valley section betweenSławsko and Staniewice, mostly in close proximity to the Early Mediaeval fortifi ed site ofWrześnica. The content of the exposures indicates that the uniform cover of overbank sedimentsacross the fl oodplain emerged during the last 1000 years. It is now impossible to say when exactly, soit is unknown what the rank of the extreme fl oods which took place at the end of 19th century was, andwhat their role in forming the present fl oodplain.

Keywords: paleomeanders, Holocene, overbank deposits, fl ood, fl oodplain, Medieval fortifi ed site, Wieprza river.

Jacek Kaczmarzyk, Department of Geomorphology and Quaternary Geology, Institute of Geograpghy and Regional Studies, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland
Wacław Florek, Department of Geomorphology and Quaternary Geology, Institute of Geograpghy and Regional Studies, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland

Abstract

In the 19th century throughout Central Europe fl oods became increasingly intense; a similarsituation pertained in the area of lake districts and the coastal zone. Maximum water levels recordedat the end of the 19th century (particularly in the years 1888-1892) to the present day on many watergaugestations (particularly those located in rivers’ lower courses) were the highest ever observed.Yet in the half on 19th century the need for regulation works became increasingly apparent. On thePomeranian rivers these works began in 1860; they reached their greatest intensity in the fi rst twentyyears of 20th century.Regulation activity was conducted which led to a distinct shortening of riverbeds; on longer sectionsof the river the reduction amounted from over 12 to 20 or more percent, in some places even50%. It caused the aggravation of bottom erosion, and also lateral erosion, which was particularlyapparent beneath the water power stations.In the last few decades the ending of work that interferes with the riverbed has resulted in thegradual restoration of the primary character of Wieprza River bed. It is also worth mentioning thateven when notable fl oods have appeared (for example, in 1980), which were comparable to those thatappeared at the end of 19th century, they did not lead to any fundamental change to any section of theWieprza River bed geosystem.

Keywords: hydrotechnic structures, Wieprza river, fl ood, river bed response, reservoir, fl oodplain.

Wacław Florek, Department of Geomorphology and Quaternary Geology, Institute of Geograpghy and Regional Studies, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland
Jolanta Jaromij, Department of Geomorphology and Quaternary Geology, Institute of Geography and Regional Studies, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland
Magdalena Skwierawska, Department of Geomorphology and Quaternary Geology, Institute of Geography and Regional Studies, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland

Abstract

Since most hydrological quantities are regarded as random variables, it is important thattheir distributions of probability be identifi ed. This paper therefore presents the results of a fi tting ofmost frequently-applied probability distributions to a series of minimum yearly fl ows. Specifi cally, theseries of minimal annual discharges derived from 119 stream gauges located throughout Poland and relatingto the period 1971-1990. The main task was to adjust one of the probability distribution functionsapplied most frequently (Fig. 1). Maps generated provide for the identifi cation of several regularities.

Keywords: hydrology, Poland, fl ow, rivers, frequency distributions, low-fl ow

Adam Bartnik, Department of Hydrology and Water Management University of Łódź Narutowicza 88, 90-139 Łódź, Poland

Abstract

The objective of the investigation presented here has been to verify schemes for the developmentof cliff coasts proposed earlier by Subotowicz (1982). This is i.a. justifi ed by observationssuggesting greater differentiation to the geological structure and consequent hydrogeological characteristicsof the Southern Baltic cliffs than had been assumed by the authors of earlier works. Themeasurement data for the investigated profi les yielded by the work to date show that:

• the most dynamic zone on the coast is the beach,
• clifftops are the parts least resistant to destruction,
• the strong storms of late autumn 2004 and the 2005/06 and 2006/07 seasons proved capable of activatingthe cliffs at nine of the ten investigated profi les, though no relationship was found betweenthe lithology of the sediments building the cliffs and rates of erosion.

Keywords: coastal zone, cliff, Southern Baltic, extreme storms, erosion.

Wacław Florek, Department of Geomorphology and Quaternary Geology, Institute of Geograpghy and Regional Studies, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland
Jacek Kaczmarzyk, Department of Geomorphology and Quaternary Geology, Institute of Geograpghy and Regional Studies, Pomeranian University in Słupsk, Partyzantów 27, 76-200 Słupsk, Poland

Abstract

Sea level, which has been rising over the years, constitutes a higher reference level forstorm surges and fl oods. According to the IPCC, extreme phenomena occurred more frequently and thiscould be connected with global climate change. The work presents the relative changes of sea level anda determination of its quantitative and qualitative variability in the eastern part of the coast along thePolish Baltic Sea which was investigated for the purpose of this paper. The analysis is based upon theresults of four tide-gauges: Władysławowo, Hel, Gdynia and Gdansk–Harbour. The fi rst part of the paperexamines long-term and seasonal fl uctuations of sea level, then the paper discusses the matter of amplitudes,and the fi nal part analyses the appearance of high water levels and storm surges during the year.

Keywords: sea level change, storm surges, southern Baltic Sea

Katarzyna Marosz, Institute of Oceanography, University of Gdańsk, Poland, Piłsudskiego 46, 81-378 Gdynia, Poland
Ewa Jakusik, Institute of Meteorology and Water Management, Poland, Podleśna 61, 01-673 Warszawa, Poland