Saturday, 30 June 2018

Ongoing research of instream wood in Carpathian headwater streams

Two our scientific papers were recently published, which deals with instream wood in the headwaters draining the highest peak of the Moravskoslezské Beskydy Mts, Czech part of Western Carpathians. The main aim of the article in Forest Ecology and Management was to find controlling factors of occurrence of large and small wood under mixed forest canopy. Deciduous trees significantly contribute to increasing number of observed small wood due to the recruitment of individual branches from these trees. However, higher frequencies of small wood did not turn into its larger active-channel volumes. On the other hand, conifers were important for the observed frequency of large wood pieces because of (i) recruitment of the whole trees and (ii) longer residence time of local conifers. Additionally, less-confined valley floor also led to increasing frequency of large wood, whereas highly confined valleys are prone to formation of large wood 'bridges' above the zone of bankfull flows. This paper was prepared under cooperation with colleagues from University of Geneve.

Conceptual model of LW and SW abundance and stability based on conifer/deciduous tree species and valley confinement. 

The second paper dealing with steps created by single wood pieces was published by Ecological Engineering. Detailed characteristics of 73 log steps in managed temperate Carpathian forests were assessed together with channel- and wood-based thresholds for log step development. The upstream threshold of log step occurrence can be assigned to those locations in stream longitudinal profiles, where transport capacity during ordinary high flows exceeds the critical value for the initiation of bedload movement (suspended-mode transport is usually not able to form sedimentary wedge upstream individual spanning logs). Downstream thresholds are controlled by stream transport capacity and wood dimensions, which also correspond to the limited recruitment of large wood pieces in local managed forests. The development of a log step at a particular channel width or basin area was controlled by the wood length, but the resultant step parameters (step height and width, length of upstream sedimentary wedge and volume of stored sediments) were better correlated with wood diameter. Nevertheless, the average sediment storage generated by a log step was only 0.51 cubic meters.      
Step created by a single wood piece. 

Empirical model of the potential development of log steps in the studied channels without debris flow or hyperconcentrated flow occurrence. 

Thursday, 28 June 2018

State of the geomorphologic research in 2018

Between 25th and 27th of April 2018, we participated on the 18th conference of Czech Association of Geomorphologists. The traditional State of the geomorphologic research in 2018 conference was held in Vílanec in the hearth of the Czech Republic close to the Vysočina Geopark. The Vysočina Geopark is spread out in the landscape of Bohemian-Moravian Highland. We presented our results from ephemeral channels of semi-arid European Mediterranean mountainous landscape in Crete (Greece) and from basins of the Outer Western Carpathians (OWC) in Czech Republic. Dr. Tomáš Galia discussed the importance of large wood in the geomorphic functions of rivers and streams of an ephemeral channel typical of semi-arid European Mediterranean mountainous landscape (Sfakiano Gorge, Crete, Greece). The conference was the first occasion to present the results of research of barchelor student Tereza Matušková from our Department of Physical Geography and Geoecology. She presented results about fine wood mobility in the Sučí Stream from the Ondřejník Massif (Podbeskydská pahorkatina Hilly land, OWC). Dr. Václav Škarpich and Mgr. Tereza Macurová referred about problematic of the possibilities of restoration measures to keep and protect the multiple-thread river pattern in the Skalická Morávka National Nature Monument in OWC.
  • Galia T., Škarpich V., Tichavský R., Vardakas L., Šilhán K.: Parameters, longitudinal distribution and dynamics of large wood in a Mediterranean ephemeral stream
  • Matušková T.: Fine wood mobility in the Sučí Stream.
  • Škarpich V., Galia T., Macurová T., Ruman S., Hradecký, J.: Possibilities for sustainability of the multiple-thread Morávka River channel in the Skalická Morávka National Nature Monument.
  • Macurová, T., Škarpich V., Galia T., Ruman S., Hradecký J.:  Gravel-bar dynamics of the protected multiple-thread reach of the Morávka River.
During this year we also plan to visit the conference RiverFlow 2018 in Lyon-Villeurbanne (France) between the 5th and 8th of September 2018.

Tomáš Galia during his presentation

Tereza Matušková during her poster presentation of fine wood mobility in the Sučí Stream

Tereza Macurová during her poster presentation about gravel-bar dynamics of the protected multiple-thread reach of the Morávka River