Wednesday, 26 April 2017

New textbook released

The textbook of Fluvial geomorphology designated for students of the Department of Physical Geography and Geoecology of the University of Ostrava (author's affiliation) was released. It is written in Czech language and its aim is to present principal concepts of fluvial geomorphology as same as basics of channel hydraulics, watershed management, river restorations and modelling of morphodynamics and sediment transport. The textbook can be also useful for students of related subjects (general geomorphology, hydrology, environmental sciences, water resources engineering) and other people interested in fluvial systems. It can be ordered via secretariat of the Department (black/white softcover print, 186 pages, price 200 CZK).
Front page


Tuesday, 28 March 2017

Within the EPSILON programme for the support of applied research and experimental development of the Technology Agency of the Czech Republic, Risks identification and possibility of support of landscape natural functions in landscape protected areas influenced by climate change project was received.
Members of Czech-Rivers research group, namely associate professor RNDR. Jan Hradecký, Ph.D., assistant professors RNDr. Václav Škarpich, Ph.D., RNDr. Tomáš Galia, Ph.D. and Mgr. Stanislav Ruman, from Department of Physical Geography and Geoecology are lead partners of project. Other project partners (i) EKOTOXA  s.r.o. and (ii) T. G. Masaryk Water Research Institute, public research institution are involved in this project.
The main objective of the project is to identify risks arising from the predicted climate change impacts on the landscape and its features in the model area PLA Beskydy. On the basis of the sensitivity and vulnerability of the landscape identifying the main problems and subsequently designing variants of suitable adaptation measures and appropriate management models in order to support the main features of the landscape and thus create conditions for the existence of valuable habitats and species in the changed climate conditions. The project outcomes will be generalized and provide professional support for public administration authorities for decision making and conceptual activities in ensuring the effective conservation of PLA, taking into account climate change.

Monday, 2 January 2017

Channel bed adjustment to over bankfull discharge magnitudes of the flysch gravel-bed stream – case study from the channelized reach of Olše River (Czech Republic)


This research is dealing with the Olše River in the Czech part of the Flysch Carpathians. It summarises the results of the increased kinetic energy of flowing water of contemporary channel based on the analyse of hydraulic parameters of channel. The comparison of geodetic measurements from 1960 and 2003 was used together with the assessment of aerial photos from 1950s and present. The active Olše R. channel was narrowed from 35 m in 1955 to 24 m in 2010 in the studied reach. In some locations, the original river bed has lowered as much as 2.3 m between the years 1960 and 2003. Morphology of the Olše River channel has accelerated these erosion processes. The main reason for this is an adjustment of water flow dynamics. The unit stream power and hydraulic radius values have increased two to three times from 1960 to 2003 for 5, 20, 50 and 100-recurrence interval discharge. Incision of channel greater than 0.10-0.21m in the studied period was affected especially by change in cross-sectional geometry and lower than 0.10-0.21m may reflect other factors such as sediment disruption operating in the basin (e.g. with land-use changes, gravel mining etc.).
 
The paper has been recently published in
Zeitschrift für Geomorphologie.


Cross profiles, water level stage and w during the 100 R.I. discharge (the source of discharge data was provided by Povodí Odry Enterprise, R.I. discharges were derived from the Jablunkov-Olše gauging station) in 1960 (grey colour) and 2003 (black colour) in the studied river reach of the Olše R.: a56.163 r. km; b 57.601 r. km; c58.604 r. km; d59.773 r. km; e63.204 r. km; f64.932 r. km; g66.064 r. km; h67.426; i69.850 r. km; vertical axes – elevation (in m a.s.l.); horizontal axes – distance (in m).

Comparison of incision and change of ω from 1960 to 2003 of analysed cross-sections in the Olše R. study reach during the 5, 20, 50 and 100 R.I. discharge.

Sunday, 16 October 2016

We participated the river restoration conference in Cracow

Tomáš Galia, Jan Hradecký and Václav Škarpich participated the conference 'Towards the Best Practice of River Restoration and Maintenance', which took place 20-23/9 in Cracow (PL) under organisation of Ab Ovo Association, Institute of Water Engineering and Water Management, Krakow University of Technology, University of Agriculture in Krakow, Institute of Nature Conservation, Polish Academy of Sciences in Krakow, Institute of Geography, Pedagogical University of Krakow and Regional Water Management Board in Krakow. Tomáš Galia spoked about effects of check-dams on channel morphologies and bed sediment parameters and he also presented some possibilities to restore such type of managed streams. Václav Škarpich discussed the role of human impact connected with the increase in stream power in managed gravel-bed rivers. Many interesting topics were presented through the conference, which dealt with natural function of rivers, ecosystem services and river restorations (see the book of abstracts free available for download).  

The 3-day field trip took place immediately after the conference in a smaller group of scientists. Colleagues from Poland showed us their study locations (e.g. Czarny Dunajec, Kamienica, Biala, Bialka), where we could see incision tendencies of Carpathian gravel-bed rivers as same as 'close-to-natural' reaches with wandering river patterns and development of islands or a mountain stream with log-jams. Also the approaches of local river restorations or a flood hazard by instream wood transport were illustratively demonstrated in the field. This trip was held in a very friendly atmosphere, giving us a great opportunity to discuss (not only) the issues of gravel-bed streams with well-known colleagues from abroad. We would like to thank especially to Bartek Wyzga and Joanna Zawiejska for the preparation and organisation of this field trip and conference.      
Restored check-dam with a fish-passage (the Krzczonówka Stream). 

Newly constructed erodible corridor in the Raba River

Demonstration of instream wood flood hazard in the Czarny Dunajec

Incision in the Bialka River (Polish-Slovakian border)

Deposited instream wood after a flood in the Czarny Dunajec upstream the Czorstyn Reservoir

Logjam in the Kamienica Stream (Gorce Mts.)

Erodible corridor in the Biala River

Monday, 3 October 2016

The effects of river patterns on riparian vegetation: A comparison of anabranching and single-thread incised channels

On September 2016, study about channel changes of the Morávka River and their effect on riparian vegetation was published.
Riparian vegetation reflects the current conditions and the dynamics of streams. The floodplain vegetation along the watercourse of the Morávka River was subject to study in this project. In some reaches, the river has the natural character of an anabranching gravel-bed stream; in contrast, other Morávka R. reaches are incised into the bedrock. These cases were used to assess potential changes in vegetation conditions as evidence of negative processes taking place in the gravel-bed streams of the Beskydy Mts. The results demonstrate a higher biodiversity in the floodplain along the anabranching river channel. In contrast, the floodplain along the incised river channel shows low biodiversity values. Redundancy analysis was used to determine the relationships between plant species composition, distance from the main channel and relative elevation from the mean water level of the main channel. In addition, the results show a higher degree of change in plant species composition on the floodplain along the incised river channel. The analysis of floodplain groundwater fluctuations shows a decreasing trend in the annual maximum groundwater level.
The paper has been recently published in Moravian Geographical Reports journal.


The Morávka R.: A – single-thread bedrock-incised channel river; B – anabranching channel river reach
Photo: V. Škarpich.
 
A – Shannon-Wiener index and B – Simpson's index of phytosociological relevés in the study area of the Morávka River floodplain. Source: authors’ elaboration.

Thursday, 29 September 2016

Geomorphic impact of historical slate mining activity on gravel-bed streams

Our present research concerned on the geomorphic effect of historical mining of slate slabs on small stream channels. The mining activity in the Nízký Jeseník Mts (Eastern Sudetes) took place mainly in 19th century and almost all mines and quarries were closed until 1950s. Unusable rocks were usually deposited on dumps in front of the mine entrances and quarries. Dumps located on the hillslopes adjacent to the channels and former floodplains were studied as important inputs of coarse material for local streams and the alterations in bed grain-sizes and channel morphologies were evaluated.  The sediment supply from investigated dumps in low-order (I-III.) channels often transformed channel-reach morphologies (pool-riffles to plane beds), significantly altered adjacent and downstream caliber of bed sediments, and decreased the bankfull width near the points of active sediment inputs. This supply of larger grains into channels also increased potential stability of channel beds. By increased transport capacity of a stream, the significance of slate dumps as sediment inputs for evaluated supply limited or transport-balanced streams decreased as expressed obtained results for larger IV-order gravel-bed stream.
The paper has been recently published in Zeitschrift für Geomorphologie

Large slate dump in Deštná
Slate dump coupled with the channel - the case of the Lobník Stream.

Increased bed grain-sizes near the positions of active sediment inputs. Supplied slate slabs
significantly exceed  stream transport capacity calculated for bankfull flows.

Sunday, 4 September 2016

Inventory of large wood in the Odra River

The upper Odra River upstream Ostrava City represents unique geomorphic meandering pattern on the boundary between the Western Carpathians and Bohemian Massif. During the first week of September, the inventory of instream wood in the protected area of the Odra River took place, where the removal of large wood due to flood risk is prohibited since 2015. In total, 146 individual pieces of large wood were measured and positions of additional large wood jams (several including up to 20 logs) were mapped in ca. 4 km long reach. In addition, 32 large wood pieces were tagged in order to observe their future movement during high water stages. We assume extensive lateral supply of instream wood particularly in active meanders, which was also documented during field mapping.