WP6 Report Interactions with Structures
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WP6 Report Interactions with structures WP Responsible: PP9 – University of Ljubljana, Faculty of Civil and Geodetic Engineering, Slovenia Coordination and synthesis: Jošt Sodnik, Simon Rusjan, Mojca Kogoj, Matjaž Mikoš Lead Authors: Jože Papež, Bruno Mazzorana, Alessandro Vianello, Mateo Cesca, Helmut Habersack Contributors: LP BMLFUW - Federal Ministry of Agriculture, Forestry, Environment and Water Management, Dep. IV/5 Torrent and Avalanche PP1 Autonomeous Province of Bolzano PP2 ARPAV - Regional Agency for Environmental Protection and Prevention of Veneto - Regional Land Safety Department PP3 UNI PD TESAF - University of Padova-Department Land, environment, Agriculture and Forestry PP5 Piedmont Region PP7 IRSTEA Grenoble, Snow avalanche engineering and torrent control research unit PP9 UL FGG - University of Ljubljana, Faculty of Civil and Geodetic Engineering PP11 BOKU - University of Natural Resources and Life Sciences Vienna, Institute for Water Management, Hydrology and Hydraulic Engineering, Dep. Water-Atmosphere-Environment PP12 IZVRS - Institute for Water of the Republic of Slovenia PP13 AKL - Regional Government of Carinthia, Department 8 – Environment, Water and Nature Protection 1 Contents Introduction 4 1.1 Overview about the WP6 4 1.2 Legal boundary conditions concerning sediment continuity 5 1.2.1 EU Water Framework Directive 5 1.2.2 Flood directive 17 1.2.3 RES directive 19 1.2.4 Habitats directive 20 1.2.5 Environmental Quality Standards Directive 21 2 Aims 22 3 Chapters – WP6 Outputs 24 3.1 Report on improved concepts of responses of torrent/river control structures to floods and debris flow impacts (including wood) 24 3.1.1 Introduction – up-to date insight on the main driving forces for improving flood control management in the European Union and Alpine Space context 24 3.1.2 Flood control and sediment management in the context of integral flood risk management – SedAlp recommendation on an improved planning approach 27 3.1.3 Modern protection concepts with cross-sectional structures in torrent and erosion control in Alpine torrent catchments 28 3.1.4 Effectiveness of checkdams 38 3.1.5 Effectiveness of barriers documented during events in Austria 39 3.1.6 Check dams influence on sediment transport in steep slope stream 41 3.1.7 Analysis of the protection work system on the Maira river 44 3.1.8 Concept of torrent control in the Bistričica torrent (Slovenia) 51 3.1.9 Maintenance of torrent protection structures 56 3.1.10 Conclusions and recommendations 58 3.1.11 References 63 3.2 Guideline for planning/designing of efficient torrent control structures with low impact on sediment continuity between upstream torrential headwaters and downstream river reaches 71 3.2.1 Background 71 3.2.2 Problem description 72 3.2.3 Design Framework 74 3.2.4 Procedures for improved planning 80 1 2 3.2.5 Good practice examples 91 3.2.6 Conclusions and recommendations 102 3.2.7 References 104 3.3 Guideline for improved planning of hydropower plants aimed to improve the longitudinal sediment continuity between upstream torrential headwaters and downstream river reaches 112 3.3.1 Background 112 3.3.2 Problem and processes description 118 3.3.3 Procedures for improved planning: actual Sediment Management Plans 136 3.3.4 Good practices: Management Plans' optimizations 149 3.3.5 Conclusions and Recommendations 153 3.3.6 References 156 3.4 Guideline for planning and designing of effective flood protection systems, river training and restoration projects that have lower impact on sediment continuity 160 3.4.1 Background 160 3.4.2 Problem description 160 3.4.3 Processes and relations 164 3.4.4 Procedures for improved planning 169 3.4.5 Practice examples 178 3.4.6 Conclusions and recommendations 184 3.4.7 References 186 4 Conclusions and recommendations 188 4.1 Policy makers 189 4.2 Practitioners 189 4.3 Researchers 190 5 Annex 191 2 3 Executive Summary Work package 6 (WP6) focuses on the interaction between structures and sediments. Since the structures in rivers and torrents are designed to perform different functions, the work in WP6 was divided in four main research topics. Four main expected outputs of the WP6 are provided. These include one report on improved concepts of responses and three guidelines: Guideline on effective planning and design of torrent structures with low impact on sediment continuity, Guideline on improved planning of hydropower plants to improve sediment continuity between torrential headwaters and downstream river reaches and Guideline on planning and designing of effective flood protection systems, river training and restoration projects with low impact on sediment continuity. Each output provides specific recommendations for Policy makers, Practitioners and Researchers. The first report deals with improving flood control management in European Union and flood control and sediment management in the context of integrated flood risk management. Modern protection concepts with transverse structures in torrents and erosion control in Alpine torrential catchments are presented and the importance of the prevailing sediment transport process in the torrent is pointed out. Besides the theoretical research, the results of the real case scenario research about effectiveness of barriers during flood events are analyzed. Lab experiment was applied to analyze the influence of check dams on sediment transport. Two case study concepts of protection and control system are analyzed and presented. Different approaches (design frameworks) for planning and designing of efficient torrent control structures with low impact on sediment continuity are presented. The importance and role of various input data and analysis is emphasized and the possibility of different knowledge approaches in different problem solving phases is analyzed. New procedures for improved planning are developed including analysis of various design criteria for designing sediment traps, review of construction, functionality and management of retention basins of torrent structures is prepared. Further, the methodology for torrent check dam failure hazard ranking is presented. Physical scale model is applied to refine the process comprehension and torrent control structure design. Within examples of good practice, new methods and approaches are presented. Hydropower plants have various impacts on the environment. Overview and problem description of the impacts is prepared with emphasis on the sediment transport which is affected in the upstream and the downstream reach. Procedures for improved planning including mechanical removal and flushing operations are presented and described together with positive and negative influences of the procedure. Management plans optimizations are proposed: removing of coarse sediment and re-introduction of sediments in the downstream channel reach and application of MCA (Multi Criteria Analysis) method. Anthropogenic changes in the environment caused ecological, economical and technical problems, including flood hazard and interruption of sediment continuity. Detailed description with theoretical background of sediment related problems is prepared. Proposed procedures for improved planning include counter measures for bed degradation, tools for river bed widening, river bed implementations and consideration of sediment transport in flood risk management. Two practice examples are described with all the implemented measures and actions. 3 4 Introduction 1.1 Overview about the WP6 Sediment transport in running waters with its multitude of practical consequences is among the phenomena that still defy reliable prediction despite substantial progress having been made in fundamental research and the development of numerical methods. Further intensive study will be needed to acquire the capability to provide safe information that will stand the test of practice in the fields of morphological stream development, reservoir sedimentation, sediment deposition in floodplains, breach of dams, etc. There are many reasons for this unsatisfactory situation, and measurement results are among them. Intensive soil erosion and sediment transport process can worsen the agricultural conditions in endangered areas; high sediment concentrations in rivers can present threat to aquatic organisms and influence the water quality; turbine abrasion and sedimentation in the hydropower plant reservoirs can cause significant economic damage. Therefore, sediment transport monitoring is one of the pre-required steps to improve the knowledge about erosion and sediment process in catchments. New knowledge can be applied during the planning/design of different structures and also for the integrated sediment management, which is composed of several important steps. Identification and quantification of sediment sources is one of the first steps. This information is then used with addition to the sediment connectivity study to estimate the sediment yields which are transported to the river network (basin-scaled sediment dynamics and sediment transport monitoring are included in WP4 and WP5) Then, a bed load and suspended load monitoring system is designed based on the information gathered from the previously mentioned steps. High-frequency sediment transport data with the addition of the historical information are the inputs of the sediment management. Various man-made structures like hydropower plants, water supply reservoirs, check dams, and other torrent/flood control structures have an enormous impact on sediment transport (alterations of flow behaviour