Roman Soja
Articles
Changes of the Vistula river channel and floodplain in the last 200 years
Geographia Polonica (2006) vol. 79, iss. 2, pp. 65-87 | 
Full text
Abstract
The Vistula River is a typical Central-European river flowing from the mountains acrossbasins and upland belts to the lowlands. The Vistula valley is modelled by a river with a complexhydrological regime. In its upper reaches, floods driven by summer rainfall prevail, while in thelower reaches snowmelt floods are important. Deforestation favoured a natural propensity forriver braiding. In the mid-19th century, the channelization of the upper Vistula (in the Carpathianforeland) and the lower reaches was commenced with, while the middle streach was leftin a natural state, such that the river has in places preserved a braided pattern up to the presentday. The channelization followed by construction of reservoirs caused downcutting and aggradationto occur, such that opposing tendencies were observed in particular reaches of the riverchannel. In addition, flood embankments confined aggradation to the intra-embankment area.Thus, the functioning of the Vistula River system is largely controlled by diverse human activity.Unconstrained flow and river load transport along the whole river length are only partly possibleduring extreme floods. The present-day adjustment tendencies also relate to ongoing changes inland-use in the drainage basin, as well as on global climatic changes.
Keywords: Vistula River, channelization/regulation, present-day changes of floodplain, downcutting, aggradation
[alajczak@o2.pl], Institute of Geography Pedagogical University of Krakow Podchorążych 2, 30 -084 Krakow: Poland
[plitjo@twarda.pan.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Twarda 51/55, 00‑818 Warszawa, Poland
[soja@zg.pan.krakow.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Św. Jana 22, 31-018 Kraków, Poland
[starkel@zg.pan.krakow.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Św. Jana 22, 31-018 Kraków, Poland
Rainfall, runoff and soil erosion in the extremely humid area around Cherrapunji, India
Geographia Polonica (2002) vol. 75, iss. 1, pp. 43-65 | Full text
Abstract
The present paper includes a characterization of the environment in the extremely humid Cherrapunji region (with annual rainfalls from 8 000 to 24 000 mm), as well as a description of a new project and preliminary observations on runoff and soil erosion. Due to deforestation, soils are degraded. The investigation is based on existing meteorological records, measurements of rainfall intensity by way of pluviometers, and observations of selected geomorphological and hydrological processes conducted in an experimental catchment. Heavy rains mainly occur during late evening and continue till morning. The runoff follows the heavy rains immediately, even if the soil profiles may absorb 100 mm of rainfall over 3-4 hours. Deeper layers of the soil profile are still satura-ted during the first half of the dry season. During the rainy season, saturated sheet flow also prevails in the valley bottoms. The present-day rate of soil erosion is very low due to heavy overland How continuing for centuries, and the formation of a stony pavement on slope surfaces as well as of river channels cut in resistant rocks with iron crusts. This has been documented by measurement of ,rCs contents in soil profiles.
Keywords: rainstorm, overland flow, soil erosion, Cherrapunji plateau, '7Cs
[starkel@zg.pan.krakow.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Św. Jana 22, 31-018 Kraków, Poland
, epartment of Geography, North-Eastern Hill University, Shillong-793014, India
[soja@zg.pan.krakow.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Św. Jana 22, 31-018 Kraków, Poland
, Homerka Laboratory of Fluvial Processes, Institute of Geography, Polish Academy of Sciences, Frycowa, Poland
, department of Geography, North-Eastern Hill University, Shillong-793014, India
[pawel@zg.pan.krakow.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Św. Jana 22, 31-018 Kraków, Poland