Graduation of Ruben Frijns
13 November 2019 14:00 - Location: Lecture Hall G, Faculty of Civil Engineering and Geosciences - By: Webredactie
"Design of an adaptive weir; A case study of the replacement of weir Belfeld" | Chair of graduation:dr. ir. J.D. Bricker, supervisors: dr. ing. M.Z. Voorendt (TU Delft), dr. R.R.P. van Nooijen (TU Delft), ir. H.G. Tuin (Arcadis).
In contrast with other Dutch river parts, human measures in the upstream part of the River Meuse did not only focus on discharging surplus water, but also on retaining water in dry periods. Almost 100 years ago seven weirs were built in the River Meuse to enable transport of coals. The structures reach, due to concrete degradation, their end of technical lifetime and the manual operation does not meet the current ARBO-legislation; both make replacement of the weirs required. This thesis elaborates on a weir replacement strategy developed in 2015 at by Rijkswaterstaat organized meetings, which proposes adaptive designing of the weirs.
The approach of adaptive delta management is applied, which states that designs have to be flexible in future. An overview of the future uncertainty and the measures required in case of specific developments is given in this study by adaptation schemes. The adaptation scheme has been elaborated for the four Dutch delta scenarios DRUK, STOOM, RUST and WARM, which are based on a unique combination of the rate of climate change and socioeconomic developments. Adaptivity can be obtained by weir adaptation measures and regional adaptation measures over a particular stretch along the river. To address both the adaptivity of the river and the weirs, three design levels have been established: the global, regional and local design level.
- The global design level comprises the total dammed section of the Dutch River Meuse and two weir sections in Belgium. The series of weirs in the river still suffices the requirements. The global adaptivity is limited by agreements on water distribution and by the present soil conditions and elevation of the area surrounding the river. On this scale level no large adaptations have to be made now or in the future.
- The regional design level comprises the weir sections Roermond and Belfeld. The adaptivity of these sections is the largest of all weir sections in the global design area, since the navigation function is fulfilled by a parallel canal and (the lakes of) the Meuse River fulfil(s) the recreation and ecology function. The adaptation scheme of these two weir sections indicates what regional adaptation measures and weir adaptation measures are required per time period in each of the four delta scenarios. On basis of this adaptation scheme, it is concluded that by designing an adaptive weir, regional adaptation measures that involve undesired implications can be discarded in the future.
- The local design level addresses the geometric design of the weir Belfeld itself. An adaptive weir is proposed to replace weir Belfeld, which consists of 7 openings, including a navigation opening. The requirements to and the design of the adaptive weir are based on the adaptation scheme from the regional design level. The weir can be adapted by adding an extra weir opening, adjusting the management of the weir gates and heightening the radial gates and thus the dammed water level with a maximum of 1.2 m. This adaptivity requires a 30% increase of the initial investments, but, in the majority of the future scenarios, regional adaptation measures can be saved.
- Concludingly, a method of using adaptation schemes for designing an adaptive weir has been developed. This method results in a weir at Belfeld, which can be adapted to fulfil the changed requirements in most of the future scenarios and thus enables the discard of regional adaptation measures that involve undesired implications. In general, the used method can be applied to each weir section. By also involving stakeholders, quantitative adaptation schemes can be set up for all weir sections in the River Meuse, which thereafter can be used for the design of all new weirs.