Restoration of floodplain rivers: The 'danube restoration project' Export

@article{citeulike:2958811, abstract = {Restoration concepts for large river systems are currently in an early stage of development. Possibilities for, and constraints of, rehabilitation - both from a process-oriented view as well as from the nature conservation perspective - differ strongly according to the degree of anthropogenic changes. This requires precisely formulated amelioration goals. Well-conceived and thoroughly analysed case studies are necessary to better understand reversibility, direction and time scale of changes, and the sustainability of various scenarios. It is important to plan controllable set-ups with long-term monitoring in the pre- and post-implementation phases of restoration programmes. In order to achieve these goals, monitoring instruments have to be developed and calibrated that allow the definition and analysis of improvements. Finally, controlled restoration programmes offer the opportunity for large-scale experiments to test overall concepts and hypotheses and have an important heuristic value to improve the understanding of river ecology in general. Copyright {\copyright} 1999 John Wiley \& Sons, Ltd.}, address = {Department of Limnology, EAWAG/ETH, CH-8600, Duebendorf, Switzerland}, author = {Schiemer, F. and Baumgartner, C. and Tockner, K.}, citeulike-article-id = {2958811}, citeulike-linkout-0 = {http://www.scopus.com/record/display.url?view=extended&origin=resultslist&eid=2-s2.0-0033061049}, comment = {Characteristics of the Upper Danube The Danube is one of the main drainage systems in Europe. Its catchment extends from Germany to the Black Sea, forming a major West to East biogeographic corridor and migration rout of nearly 3000km in lenght. […] Like all large rivers in Europe and North America (see, e.g. Petts et al., 1989; Dynesius and Nilsson, 1994; Ward, 1998), the ecology of the Danube has been considerably affected by land use and changes in its catchment, by pollution and most importantly by hydro-engineering. Over the past 50 years more than 90\% of the Upper Danube and its major tribunaries have been dammed for hydropower production (Fig.1b). The remaining few stretches have been sverely affected by regulation. […] The long-term monthly mean water levels in the Austrian stretch are highest in June and lowest in November, with an amplitude of 2.5m. However, water level fluctuations are strong and stochastic and spates {fluten} can occur throughout the year. High current velocities in the main channel and coares-grained substrates characterize the Austrian Danube as hyporithral river. Historically, the dynamic hydrology and the high sediment transport from the Alps produced large alluvial fans, especially in the tectonic basins below geomorphological constrictions. This was accompanied by a braided river course with extended floodplains prior to regulation. […] This holds true for the 50km river reach downstream of Vienna to Bratislava. This reach, althoug strongly impacted by regulation, represents one of the last remnants of a river-floodplain system. Here, the key functional attributes of floodplains - the hydrological dynamics, flood pluses and bed load transport - are partially operative and a high potential for re-establishing hydrological dynamics remain. As the largest remnant of alluvial landscape in Europe, this strech was declared a National Park in 1996. The main features of the regulation schem and its immediate and long-term effects in this area are schematically outlined in Fig.2. The regulation scheme started in 1875 and represented a major engineering feat at that time. […] The main engineering approach was to create a singel, straightended channnel, stabilized by riverside embankments and ripraps. The former arms of the original braided system were cut off. Weirs had to be built in order to retain the water level in the floodplain. The riverside embankments reduced the hydrological interaction with the floodplains and large levees completely cut off parts of the former floodplains from erosive, scouring flood flow. The immediate effect were: - A loss of riverine inshor habitat, which had strong imapcts on inshore retention characteristics (Schiemer et al, 1991) and on the habitat value for rheophilic organisms, e.g. as nurseries for riverine fish (Schiemer and Spindler, 1989; Schiemer et al., 1991) - Reduced hydrological connectivity both of groundwater exchange and open surface water connections between river and floodplains - lowered water table - strongly reduced geomorphic processes in the floodplain and complete change in the pattern of cout and fill - a concentration of the erosive forces on the main channel bed This initiated a deepening on the cannel by approximately 1.5m since 1875. The present average rate of degradation is 1.5-2cm per year along the free-flowing stretch downstream of Vienna. This means a continous dewatering of the floodplains. In combination with sediment accumulation and terrestrialization processes in the isolated waterbodies, the aquatic system is subject to ongoing disintegration and fragmentation. With lateral distance from the main channel, sedimentation and water retention increas, while erosive processes, hydrological connectivity and the amplitude of the hydrograph decrease. Outside the levees, these changes are strongly enhanced. [...] A master plan for the National Park area has been elaborated [...] The aims are (1) to reduce the channel deepening by adding coarse-grained (oversized) gravel, (2) to rais the water thabel by narrowing the shipping channels with groynes and (3) to enhance lateral integration and exchange processes between river and floodplains. Restoring the hydrological connectivity between a river and its floodplain is - from an ecological perspective - recognized as the most important step. (Schiemer, F.; Baumgartner, C.; Tockner, K. (1999): Restoration of floodplain rivers: The 'danube restoration project'. In: River Research and Applications, Jg. 15, H. 1‐3, S. 231‐244. Online verf\"{u}gbar unter http://www.scopus.com/scopus/record/display.url?view=extended\&origin=resultslist\&eid=2‐s2.0‐0033061049, S. 232-234)}, journal = {River Research and Applications}, keywords = {0print, 1dipl, 1limno, 1npda, floodplains, restoration, river}, number = {1-3}, pages = {231--244}, posted-at = {2008-07-03 12:30:22}, priority = {2}, title = {Restoration of floodplain rivers: The 'danube restoration project'}, url = {http://www.scopus.com/record/display.url?view=extended&origin=resultslist&eid=2-s2.0-0033061049}, volume = {15}, year = {1999} }

TY - JOUR ID - citeulike:2958811 L3 - citeulike-article-id:2958811 N2 - Restoration concepts for large river systems are currently in an early stage of development. Possibilities for, and constraints of, rehabilitation - both from a process-oriented view as well as from the nature conservation perspective - differ strongly according to the degree of anthropogenic changes. This requires precisely formulated amelioration goals. Well-conceived and thoroughly analysed case studies are necessary to better understand reversibility, direction and time scale of changes, and the sustainability of various scenarios. It is important to plan controllable set-ups with long-term monitoring in the pre- and post-implementation phases of restoration programmes. In order to achieve these goals, monitoring instruments have to be developed and calibrated that allow the definition and analysis of improvements. Finally, controlled restoration programmes offer the opportunity for large-scale experiments to test overall concepts and hypotheses and have an important heuristic value to improve the understanding of river ecology in general. Copyright © 1999 John Wiley & Sons, Ltd. IS - 1-3 JF - River Research and Applications AD - Department of Limnology, EAWAG/ETH, CH-8600, Duebendorf, Switzerland EP - 244 TI - Restoration of floodplain rivers: The 'danube restoration project' VL - 15 SP - 231 KW - 0print KW - 1dipl KW - 1limno KW - 1npda KW - floodplains KW - restoration KW - river N1 - Characteristics of the Upper Danube The Danube is one of the main drainage systems in Europe. Its catchment extends from Germany to the Black Sea, forming a major West to East biogeographic corridor and migration rout of nearly 3000km in lenght. […] Like all large rivers in Europe and North America (see, e.g. Petts et al., 1989; Dynesius and Nilsson, 1994; Ward, 1998), the ecology of the Danube has been considerably affected by land use and changes in its catchment, by pollution and most importantly by hydro-engineering. Over the past 50 years more than 90% of the Upper Danube and its major tribunaries have been dammed for hydropower production (Fig.1b). The remaining few stretches have been sverely affected by regulation. […] The long-term monthly mean water levels in the Austrian stretch are highest in June and lowest in November, with an amplitude of 2.5m. However, water level fluctuations are strong and stochastic and spates {fluten} can occur throughout the year. High current velocities in the main channel and coares-grained substrates characterize the Austrian Danube as hyporithral river. Historically, the dynamic hydrology and the high sediment transport from the Alps produced large alluvial fans, especially in the tectonic basins below geomorphological constrictions. This was accompanied by a braided river course with extended floodplains prior to regulation. […] This holds true for the 50km river reach downstream of Vienna to Bratislava. This reach, althoug strongly impacted by regulation, represents one of the last remnants of a river-floodplain system. Here, the key functional attributes of floodplains - the hydrological dynamics, flood pluses and bed load transport - are partially operative and a high potential for re-establishing hydrological dynamics remain. As the largest remnant of alluvial landscape in Europe, this strech was declared a National Park in 1996. The main features of the regulation schem and its immediate and long-term effects in this area are schematically outlined in Fig.2. The regulation scheme started in 1875 and represented a major engineering feat at that time. […] The main engineering approach was to create a singel, straightended channnel, stabilized by riverside embankments and ripraps. The former arms of the original braided system were cut off. Weirs had to be built in order to retain the water level in the floodplain. The riverside embankments reduced the hydrological interaction with the floodplains and large levees completely cut off parts of the former floodplains from erosive, scouring flood flow. The immediate effect were: - A loss of riverine inshor habitat, which had strong imapcts on inshore retention characteristics (Schiemer et al, 1991) and on the habitat value for rheophilic organisms, e.g. as nurseries for riverine fish (Schiemer and Spindler, 1989; Schiemer et al., 1991) - Reduced hydrological connectivity both of groundwater exchange and open surface water connections between river and floodplains - lowered water table - strongly reduced geomorphic processes in the floodplain and complete change in the pattern of cout and fill - a concentration of the erosive forces on the main channel bed This initiated a deepening on the cannel by approximately 1.5m since 1875. The present average rate of degradation is 1.5-2cm per year along the free-flowing stretch downstream of Vienna. This means a continous dewatering of the floodplains. In combination with sediment accumulation and terrestrialization processes in the isolated waterbodies, the aquatic system is subject to ongoing disintegration and fragmentation. With lateral distance from the main channel, sedimentation and water retention increas, while erosive processes, hydrological connectivity and the amplitude of the hydrograph decrease. Outside the levees, these changes are strongly enhanced. [...] A master plan for the National Park area has been elaborated [...] The aims are (1) to reduce the channel deepening by adding coarse-grained (oversized) gravel, (2) to rais the water thabel by narrowing the shipping channels with groynes and (3) to enhance lateral integration and exchange processes between river and floodplains. Restoring the hydrological connectivity between a river and its floodplain is - from an ecological perspective - recognized as the most important step. (Schiemer, F.; Baumgartner, C.; Tockner, K. (1999): Restoration of floodplain rivers: The ’danube restoration project’. In: River Research and Applications, Jg. 15, H. 1‐3, S. 231‐244. Online verfügbar unter http://www.scopus.com/scopus/record/display.url?view=extended&origin=resultslist&eid=2‐s2.0‐0033061049, S. 232-234) AU - Schiemer, F AU - Baumgartner, C AU - Tockner, K PY - 1999/// UR - http://www.scopus.com/record/display.url?view=extended&origin=resultslist&eid=2-s2.0-0033061049 ER -