S. Wurms, P.M. Schroeder www.baw.de
Outline Background and project aim The research programme KLIWAS Hydraulic bottlenecks under changing hydrological conditions River training options for adaptation to extreme low water situations Fairway within fairway Flexible, temporarily acting regulating structures Summary Page 2
1. Background and project aim Rhine: Frequency and duration of low water periods might be increased due to future climate changes Adverse effects on navigation: Decrease of cost effectiveness due to reduction of maximum transportation capacity Decrease of ease and safety due to constriction of navigable fairway width Identification of adaptation measures to Rhine nearby Oberwesel during low water sustain navigation under extreme low water conditions Page 3
2. The research programme KLIWAS KLIWAS - Impacts of climate change on waterways and navigation Analysis of the vulnerability and development of potential adaptation measures 30 projects, financed by the Federal Ministry of Transport, Building and Urban Development (BMVBS) Research institutions: - Federal Waterways Engineering and Research Institute (BAW) - Deutscher Wetterdienst - DWD (National Meteorological Service) - Federal Institute of Hydrology (BfG) and - Federal Maritime and Hydrographic Agency (BSH) Page 4
2. The research programme KLIWAS Ensemble and multi-model approach: combination of different IPCC emissions scenarios, global and regional climate models with subsequent models result in a span of projected quantities (e.g. discharge) KLIWAS model chain 6. Navigational models source: BMVBS (Ed.) (2009): Conference Proceedings KLIWAS Impacts of Climate Change on Waterways and Navigation in Germany First Status Conference, Bonn. (modified) 7. Economical models Page 5
3. Hydraulic bottlenecks under changing hydrological conditions Area under investigation: Rhine 1320 km in total; navigable: 884 km MQ = 2300 m³/s (German Dutch border) Transport performance: 2006: 43.4 billion ton-kilometres (67.8 % of total German inland waterway transportation) Source: Wasser- und Schifffahrtsdirektion Suedwest (2007): Kompendium der Wasser- und Schifffahrtsdirektion Südwest. (modified) Page 6
3. Hydraulic bottlenecks under changing hydrological conditions changes of NM7Q (hydrol. summer) in near (red) and far (purple) future Hydraulic analysis (2D-HN model TELEMAC-2D): Present conditions of the waterway under changing hydrological conditions Identification of potential future bottlenecks e.g. gauge Kaub: 2021 2050: +/- 10 % 2071 2100: - 25 bis - 10 % Bandwidth of projected discharges Sensitivity analysis using reduced low water discharges GlQ - 5% up to GlQ - 25%. (QlQ 2002_Kaub = 750 m³/s; equivalent low Source: Nilson, E., Carambia, M., Krahe, P. (2010): Low Flow Changes in the Rhine River Basin, In: Results of the RheinBlick2050 Project. CHR Report No. I-23. water discharge) Page 7
3. Hydraulic bottlenecks under changing hydrological conditions River Rhine reach Mainz St. Goar (Rhine-km 493-557) Rhine-km 557.5 guaranteed fairway-depth between Rhine-km 508 and 557 only 1,90 m below GlW 2002 (GlW 2002 : equivalent low water level) km 508 Rhine-km 493.0 Page 8
3. Hydraulic bottlenecks under changing hydrological conditions Volume of shoals within the existing fairway per running river kilometre due to decreased water levels as a function of reduced low water discharges GlQ 2002 volume of shoals within fairway [m³] 4000 3000 2000 1000 0 GlQ2002 GlQ2002-5% GlQ2002-15% GlQ2002-25% guaranteed fairway-depth below GlW 2002 2.10 m 1.90 m 493 503 513 523 533 543 553 Rhine-km riverbed: condition 2004/ 2006 Page 9
4. River training options for adaptation to extreme low water situations Width-reduced, deepened low water fairway ( Fairway within fairway ) in addition to existing fairway; utilisation of excess depths reduction of maintenance costs compared to fairway deepening on entire width Flexible, temporarily acting or fixed regulating structures Page 10
4.1 Fairway within fairway Determination of the minimum fairway width: KLIWAS Project 4.04 Minimum width of fairways for safe and easy navigation Navigational dynamic models (PeTra1D, PeTra2D) Additional safety distance between ship/ ship and ship/ bank Additional width due to a human factor (Determination by using an autopilot including a human factor model) Source: Wurms, S., Schroeder, P.M., Weichert, R.B., Wassermann, S. (2010): Strategies to overcome the possibly restricted utilisation of fairways due to climate changes, River Flow 2010, 08. - 10.09.2010, Braunschweig. Page 11
4.1 Fairway within fairway Hydraulic analysis of a deepened Fairway within fairway shows: Small decline of water levels (< 0.01 m) Decrease of bed shear stresses within the dredging areas increase of aggradation tendencies Development of regulating structures aiming at the decrease of aggradation tendencies Dredging area Fairway within fairway (depth of 2.10 m below WLGlQ 2002 25 % ) Page 12
4.1 Fairway within fairway Example of a regulating structure for increasing bed shear stresses within a dredging area of the Fairway within fairway Training wall nearby Bingen (Rhine-km 525) Dredging area Fairway within fairway (depth of 2.10 m below WLGlQ 2002 25 % ) Page 13
4.1 Fairway within fairway Effect of the training wall: Increase of bed shear stresses within dredging areas No adverse effect on water levels during flood Future work: Optimisation of the regulating structure by means of a 2D-morphodynamic model Page 14
4.2 Flexible, temporarily acting regulating structures Potential option in case of non-applicability of fixed regulating temporary closing of a branch structures (no flood neutrality, obstacle for navigation, ecology, insufficient hydraulic effect ) Effect would be limited to low water discharges Constructional aspects further investigations required Example: Temporary closing of a branch of the river during low water Option for regulation? location of a shoal in case of reduced low water discharges Page 15
4.2 Flexible, temporarily acting regulating structures Hydraulic effect of the temporary closing of the branch Gaining flow depth upstream of the bifurcation up to 0.3 m during GlQ 2002 25 % (approx. 0.14 m at the shoal 1.5 km upstream) Discharge through dammed branch for ecological reasons (approx. 0.2 m/s): Decrease of regulation effect of about 25 % at the shoal 1.5 km upstream of the bifurcation location of shoal in case of reduced low water discharges Page 16
5 Summary Rhine: Decrease of low water discharges expected in the far future hydraulic sensitivity analysis shows an increase of hydraulic bottlenecks Width-reduced, deepened Fairway within fairway : Improvement of the navigability during extreme low water from a technical point of view Flexible, temporarily acting regulating structures are potentially suitable for gaining flow depth during extreme low water periods further investigations required Potential of adaptation to sustain navigation under extreme low water conditions Page 17
Thank you for your attention! www.kliwas.de KLIWAS project 4.03: Options for the regulation and adaptation of hydraulic engineering measures to climate induced changes of the discharge regime Dr.-Ing. S. Wurms Dr.-Ing. P.M. Schroeder Bundesanstalt für Wasserbau (BAW) Bundesanstalt für Wasserbau (BAW) sven.wurms@baw.de michael.schroeder@baw.de 0049-(0)721-9726-5510 0049-(0)721-9726-3730 Page 18