Report from REFORM Summer School (Wageningen, Netherlands)

Dr. Tomáš Galia and Dr. Václav Škarpich participated to Summer School 'Restoring Regulated Streams linking Theory and Practice' (link). It was organized by REFORM (REstoring rivers FOR effective catchment Management - see link). The Summer School was realized for 3-day programme from June 27 to June 29, 2015. 

Day 1st (June 27, 2015) started with an introduction and field visit of two contrasting stream restoration, namely: (i) Restoration programme Leuvenumse and Hiederse Beek, (ii) Stream restoration project Lunterse Beek.

 Fig. 1: Floodplain reconnection (for fish population - reconnection to spawning area) - Leuvenumse and Hiederse Beek.

Fig. 2: Feeding-sand (sand suppletion into the river channel) - Leuvenumse and Hiederse Beek.

 Fig. 3: Accumulated sand from feeding-sand (man affected sand suppletion) - Leuvenumse and Hiederse Beek.

 Fig. 4: Addition of wood into the river channel system - Leuvenumse and Hiederse Beek.

 Fig. 5: Addition of wood into the river channel system - Leuvenumse and Hiederse Beek.

 Fig. 6: Stream restoration of the Lunterse Beek.

 

Day 2nd (June 28, 2015) offered the theoretical background of assessing hydromorphological modification of streams and rivers and identifying appropriate restoration measures considering the socioeconomic context. The main topics were presented by: Prof. Ian Cowx, Prof. Angela Gurnell, Prof. Massimo Rinaldi, Dr Christian Wolter, Dr Nikolai Friberg, Dr Jochem Kail and  Dr Gertjan Geerling (see link to lectures video).

Fig. 7: First lecture about 'Planning Stream and River Restoration and Cost-
Benefit Analysis' performed by Prof. Ian Cowx.

 

Day 3rd (June 29, 2015) was be given a case study and work in groups to plan of restoration schemes based on the practices from previous field visit and theoretical background from lectures. The day was finished by presenting of restoration scheme by each group.

Significance of the coarsest bed fraction in flysch headwater streams

Boulders in steep headwater streams play an irreplaceable role in hydraulics, sediment transport and bed stability within this part of fluvial net. A few months ago, our new publication  has been released in Geografiska Annaler: Series A, Physical geography dealling with the connectivity of the coarsest fraction in Beskydian steep streams. Also, effects of past disturbances (debris-flows) and present lateral sediment supply was discussed in this paper. Debris-flow affected channels indicated more frequent occurrence of larger boulders in bed sediments and limited adjustments to contemporary fluvial processes (e.g. incision). On the other hand, bed sediments in channels void of past debris-flow activity often reflected lateral sediment inputs (e.g. bank failures) and trends of erosion or deposition. This study directly followed our previous paper published in Moravian Geographical Reports, which described downstream trends of coarse bed sediments and clustering of bed sediments reflecting recent fluvial processes in one of headwater stream. Other paper discussing bedload transport of the coarsest bed fraction in relation to recent geometrical parameters of steep channels and transformation of channel-reach morphology during bankfull and high-magnitude discharge is in review. The study will summarize our bedload transport observations (Q20 flood 2010, bankfull event 2011, Q5 flood 2014), contemporary fluvial processes (incision, aggradation) and connectivity of boulder and cobble fraction in local steep channels.   

Sediment Matters (Springer)

Source of picture: <http://www.springer.com/>

New book will be published by Springer - a global publishing company. Book with title Sediment Matters (link) was edited by Peter Heininger and Johannes Cullman. Book presents insights into the complex processes controlling sediment behavior in river basins and into state of the art integrated sediment management concepts.

We participate to chapters:

• Sediment transport in headwater streams of the Carpathian Flysch belt: its nature and recent effects of human interventions.

• Aspects of sediment transport in single-thread and anabranching river channels in flysch Carpathians (a case study from the Czech Republic).
  
  
   

New Czech Science Foundation (GACR) Project

Assoc. Prof. RNDr. Jan Hradecký, Ph.D. and RNDr. Václav Škarpich, Ph.D. are members of research team for realization of project - GAČR: 15-02067S (2015-2017) – Optimalization of dendrogeomorphic methods in landslide research. Project will be realized during the years 2015 – 2017. Research will focused to defining optimal spatial position and number of trees for field sampling, determining optimal age/size of trees that most sensitively reflect landslide movements and increasing the efficiency of landslide signal extraction from tree-rings. 

Source of picture: http://www.gacr.cz/en/

A complex approach for evaluation of sediment (un)balance in a steep headwater channel

A new paper was published in Catena, where a dendrogeomorphic approach was combined with ERT sounding and bedload transport simulations to estimate sediment budget during high-magnitude flood in a steep channel. It has been resulted from the cooperation with the dendrogeomorphic section of the Department of physical geography and geoecology, University of Ostrava. The methodology and results of this research were also presented on the Conference of Association of Slovac geomorphologists in Snina in October 2014. 

Sediment (un)balance budget in a high-gradient stream on flysch bedrock: A case study using dendrogeomorphic methods and bedload transport simulation

Detailed quantification of material supply into stream channels is crucial for determining sediment (un)balance budget during flood events. Unfortunately, existing quantification methods require long-term field monitoring; otherwise, there is an insufficient amount of usable data. In this study, we introduce a new approach, based on dendrogeomorphic methods, to determine the volume of material supply generated from flysch high-gradient stream bank failures. This approach was supplemented by 1D sediment transport modelling, using a TOMSED model.

We analysed 138 cross-sections from the roots of predominantly broad-leaved trees, which were exposed in bank failures from different floods. Using the spatial position of the roots and dating the exposure time, we determined the volume of material supply into the channel during the last flood, in 2010. In-channel sediment transport was analysed on 14 cross-sections, and the channel sediment thickness was estimated using the geophysically based ERT (Electrical Resistivity Tomography) method.

The total volume of material loss during the 2010 flood within the study area, according to the TOMSED model, was found to be at least 300 m3. This means that the calculated total volume of sediment supply resulting frombank failures during the flood (63.9 m3 based on dendrogeomorphic methods) was significantly lower than the calculated bedload transport for the entire study area. This finding implies that contemporary sediment sourcescannot adequately cover the transport capacity during high-magnitude flood events, and in general, in-channel erosion processes prevail.

Documentary Movie about Ostravice River (All rights reserved Czech Television - Česká televize ČT - Public Broadcast)

New documentary movie about the Ostravice River and ecology, water management, fluvial geomorphology in this river basin. With Assoc. Prof. RNDr. Jan Hradecký, Ph.D.

from the June 15, 2014 - Czech Television public broadcast

Interview about rivers in Czech Republic (All rights reserved Czech Radio - Český rozhlas ČRo - public broadcast).

Interview with Assoc. Prof. RNDr. Jan Hradecký, Ph.D. about water management and anthropogenic pressure on gravel-bed channels in the Czech Republic.

link to interview

from the May 5, 2014 - Czech Radio public broadcast