Wooden cribwall on Slovenian water courses SedAlp Pilot Area ‐ Torrent Bistričica Papež, J.1, Repnik Mah, P.2,3 Krivograd Klemenčič, A.2 1Hidrotehnik, d. d., Slovenčeva ulica 97, 1000 Ljubljana ([email protected]) 2Inštut za vode Republike Slovenije, Hajdrihova 28 c, 1000 Ljubljana ([email protected]) 3Slovenian River Restoraon Centre, Hajdrihova 28 c, 1000 Ljubljana ([email protected])

INTRODUCTION ‐ Wooden cribwall through the me Wooden cribwall ‐ river engineering good pracce Wooden cribwalls (Kranjska stena in Slovene, Krainerwand in German) are very old Wooden cribwall is recognized as Slovenian river engineering good pracce, due to the 1992). It is clear that the aesthecal and funconal point of ecologically sound building technique used mainly for protecng slopes against surface erosion and rivers against fact that is has good hydro technical characteriscs (resistance to shear stress during materials are not in conflict. Wooden cribwall will be promoted as river engineering good river erosion. It is well known that these structures were constructed in Kraina () flood events, resistance over me, enable percolaon, adaptable to terrain pracce also within project SedAlp. Within the project wooden cribwall will be built on already back in 1700 (Florineth et al., 2002), from where also the name of technique characteriscs etc.), high coincidence with landscape (in mountainous / hilly region), low the Torrent Bistričica. origin (Schiechtl in Stern, 2002, Urbajs 2010, Rhein‐Zeitung 1996). Extensive negave impact on environment (in case of vegetated wooden cribwall with autochthon construcon of wooden cribwalls was present ll 1970s when concrete construcons for plants, adapted to natural channel characteriscs and bank slope, enabling lateral the most part replaced this old technique. Nevertheless construcon of wooden connecvity between channel and riparian zone etc.) and high socio‐economical value Wooden cribwall – Intangible Cultural cribwalls have never been disconnued in hard accessible parts of watersheds, where (improving the value of human environment, strengthening of region characteriscs by construcng with mechanisaon is impossible. using local materials, compability with recreaonal and tourism acvies, represenng Heritage of Slovenia cultural and technical heritage, acceptable cost of construcon and maintenance). Nowadays there is evident increase of wooden cribwalls construcon, also due to the fact, that river engineering works has to be harmonised with environmental needs, Wood, stone, specially the one obtained from the torrent ‐ beds, and the combinaon of Wooden cribwall is symbol of tradional river and torrent engineering in Slovenia and landscape planning and socio‐economical demands. Technique in general stays the same the two, are preferred materials not only from aesthecal, but also from the funconal represents technical and cultural heritage. It was and sll is strongly connected with through the me ‐ parcular stages of construcon are improved or simplified, what and raonality point of view. The energy consumpon for building with wood and stone people that work and live with rivers. Therefore wooden cribwall was included in Register represent higher applicability of wooden cribwall on the terrain. There were built is much lower than that with concrete, steel‐concrete or similar materials. If we consider of Intangible Cultural Heritage in 2013. Wooden cribwall in general represents numerous wooden cribwalls in Slovenia, especially in the Alpine region, where this that concrete cross‐seconal structures last 4 mes longer than those made of wood, the connecon between knowledge and experiences form the past with demands of technique is recognized as very appropriate for river (torrent) erosion protecon. energy cost for building wooden structures is sll 4,2 mes lower (Hitsch in Weinmeister, contemporary society in the future.

Figure 1: Wooden cribwall on the Dolinka River Figure 2: Wooden cribwall on the River Figure 3: Wooden cribwall on the Torrent Kolovec Figure 4: Building of wooden cribwall on the Pšata River

Figure 5: Wooden cribwall on the River Figure 6: Wooden cribwall on the Pšata River Figure 7: Cribwalls on the Torrent Čerinjščica Figure 8: Natural check‐dams ‐ source of idea for the wooden cribwalls? Figure 9: Building of wooden cribwall on the Pšata River

SedALP PROJECT PILOT AREA ‐ TORRENT BISTRIČICA WATER MANAGEMENT PREVENTIVE MEASURES & DISSEMINATING of SedALP results: „Wooden Cribwall on SedALP test bed Bistričica torrent“ ‐ Integral and environmental friendly Torrent & Erosion Control in Slovenia finalisaon ll the end of the June 2015 Slovenia faces different forms of erosion, among which water erosion is parcularly significant. The most significant are torrent outbursts, extreme sediment transport and debris flow events, landslides, rockfall and avalanches. 44 % of the area is potenally at risk by erosion, one third of the area is Communicaon objecves SLOVENIA considered as unstable or condionally stable. Almost one quarter of Slovene territory are torrenal  Environmental‐sound watersheds, where the erosion phenomenon can obtain larger dimension and cause major damage structural protecon Figure 10: Locaon of Bistričica when precipitaons are intensive. measures for benefits of local inhabitants and visitors Integrated water management begins in torrent catchments. (protecon of local Bedload transport control is successfully carried out by infrastructure) correctly posioned and designed consolidaon and retenon structures. These structures are generally integrated in a  Raising awareness of general system and therefore their funcons are interacvely public & local/regional supplemenng. Since the beginning of the organized torrent stakeholders for the control in Slovenia in 1884 (1875), quite a lot of work has been importance of integral done, and safety from erosion and torrents has been torrent / sediment substanally improved. The standard of design and execuon management of construcon torrent control works was connuously  Informing about the added‐ improved, by means of new knowledge, new materials and value of transnational new technology of works. The majority of torrent control cooperaon in the field of structures have been actually constructed on proper water, sediment & natural locaons, taking into consideraon also the best possible way Figure 11: Catchment of the Torrent Bistričica; A ‐ sediment retenon dam under the upper part hazard risk management of catchment (Štrancar dam); B – sediment transport in the middle secon with crical points; of their integraon in the landscape. C – inflow in river Kamniška Bistrica (results of SedALP partnership) The torrent control management sll faces numerous tasks, in spite of the extensive control and management work conducted in  Informing about the the past. In the control and management of torrent and erosion proceedings, outputs & areas we should always be aware that we are managing them in a results (e.g. data, methods, complex way, taking into account, technical, biotechnical, agro experiences in pilots) technical and legislave measures. Especially technical  Informing other projects & anerosion measures are those, that could have negave interested Associaon, environmental impacts. We should use them very selecvely on Iniave on the SedAlp the areas, where erosion processes are concentrated or where acvies & supporng they are progressively advancing. Environmentally adequate exchange of informaon & cross‐seconal structures consider visual (aesthecal) and usage of synergies funconal aspects. The visual aspect is always associated with the Figure 12: Erosion map of the Torrent Bistričica  funconal one and at the same me subordinated to the former. Informing and training of esp. Stone and wood are ecologically sounder materials (e.g. wooden young water/torrent experts cribwalls). Cross‐seconal structures can be specially designed as  Target groups: local, regional, to sr water flow, provide favorable condions for water life, allow naonal stakeholders (e.g. fish migraon, etc. Such consideraons however, must not affect policians), ministries, the strength and the stability of the construcon. government, general public, Increased number of weather extremes are causing increasing experts, NGOs, media (print, number, frequency and intensity of natural disasters, and because radio, tv), authories, of the economical development, the consecuve damages are administraon, other geng proporonally bigger. The significance of maintenance and projects and programmes & modernizaon of the existent torrent control structures is the EU, schools, university therefore geng larger. Only well maintained torrent control etc. structures and systems can perform the required funcon. Figure 13: Torrent erosion map & management concept from 1939 (A. Štrancar) Project: Implementaon of two wooden‐cribwalls & SedALP info tables: We have to pay more aenon to systemac measuring and analyzing of magnitude and frequency of sediment transporng Iniave of the project: SI SedALP partner PP12: events in Slovene torrents. Because of the obvious non‐maintenance of the larger number of torrent structures, Slovenia will Instute for Water of the Republic of Slovenia (IzVRS) & HIDROTEHNIK have to assign a larger share of funds to their maintenance and increase the share of funds for prevenon measures aerwards, Operave financing: Kamnik community & „Si.voda“ Fund (donaon) to preserve the balance condions in torrenal catchments. Weather extremes could become even more frequent, and the me Designe financing: Ministry & Slovenian Environment Agency (ARSO) for catching up the earlier lack of maintenance measures is running out. Expert support (info tables): SedALP PP12 IzVRS & HIDROTEHNIK

MINISTRY OF THE ENVIRONMENT AND SPATIAL PLANNING SLOVENIAN ENVIRONMENT AGENCY