The image of Civil Engineering is characterised by large steel or concrete structures that conflict with resource and environmental protection through land sealing and the displacement of ecosystems. But instead of equating Civil Engineering with building "against" nature, we show here examples where Building with Nature represents a paradigm shift towards an environmentally protective and enhancing perspective of building. This topic is becoming increasingly relevant and is a focus at the TU Braunschweig in the training of future generations of civil engineers.
In Building for Nature, for example, revitalisation measures in rivers are scientifically investigated in order to quantify the influences on an ecosystem. Building for Animals deals with questions of how ecological passability can be ensured when rivers are altered by transverse structures for human use. Building with Ecosystems explores the possibilities of ecosystem-strengthening coastal protection. Among other things, our wide sandy beaches are facing the challenge of rising sea levels, and their near-natural adaptation possibilities are examined in more detail in the area of Building with Sand.
What effect do renaturation measures have in rivers and how is biology related to physics? These are the questions addressed by the collaborative project "Wilde Mulde - Revitalisation of a Wild River Landscape", which was launched in 2015 and to which the Department of Hydraulic Engineering and River Morphology at the Leichtweiß-Institute for Hydraulic Engineering and Water Resources is contributing with its research.
River restoration, i.e. the return of a developed river to a valuable habitat, has been part of the repertoire of engineering firms since the late 1990s. However, there is still a lack of knowledge about how a measure has to be designed in concrete terms so that the river ecosystem benefits from it in the best possible way.
Based on this question, various measures to improve the river structure were planned and implemented in an approximately 20 km long section of the Mulde, a tributary of the Elbe, between Raguhn and Dessau-Roßlau. These included the installation of predatory trees, the partial restoration of a natural bank by dismantling the bank protection and the connection of a side arm.
Regular measurements of hydraulic parameters (water depths and flow velocities) and morphological parameters (grain distribution of the bed sediment and bed topography) are used to determine whether the measures lead to the desired self-dynamic development of different habitats in a small area. In the LWI's Hydraulic Engineering Laboratory, individual processes are singled out and the relationship between cause and effect is determined in parameter studies. For example, the influence of properties of a tree lying in the water (e.g. root plate diameter and tree length) at different water levels on the development of the bed (bank and scour formation) is investigated.
Together with biological and chemical data from the project partners, conclusions will be drawn about the effect on fauna and flora. The knowledge gained in this way should indicate how future renaturation measures can be planned more effectively and sustainably.
The European river network is interrupted by more than 1.3 million transverse structures of various kinds, of which about 200,000 are in Germany alone. This has an immense impact on aquatic communities, as many fish species need free paths upstream and downstream in their life cycle.
A very natural way to create ecological passability at a transverse structure is to build a bottom sluice. The use of large stones and their skilful arrangement creates a varied flow pattern similar to that of a mountain stream. This kills two birds with one stone, because both the ecological continuity and the water management purpose of the structure are guaranteed.
However, the dimensioning of bed slides so that they can be passed by all fish species and sizes occurring in the water body is still problematic. Too high flow velocities are just as unfavourable as too shallow water depths. This is where the MigRamp research project comes in and literally makes the fish their own builders.
A demonstrably functioning, i.e. continuous, bed channel on the Ilme in Lower Saxony was selected for the project. In laboratory and nature studies, underwater cameras are used to precisely record the paths of fish of various species as they migrate across the bed channel, and the properties of the current and the bed, i.e. the bottom of the water body, are measured along these so-called migration corridors using state-of-the-art methods. With their findings, the civil engineers from the LWI are making a significant contribution to making it easier for the fish to find their way.
Was ist eine „gute Küste“, an der wir sicher vor Naturgefahren, im Einklang mit der Natur, eingebettet in die gewachsene Kulturlandschaft, verantwortungsbewusst und nachhaltig leben und wirtschaften können?
Dieser sehr breit angelegten Frage geht der Forschungsverbund aus drei Niedersächsischen Universitäten an der Niedersächsischen Küste zwischen Ems und Weser nach. Im Zentrum von Ingenieuren, Ozeanographen, Landschaftsökologen sowie Sozialwissenschaften steht der ökosystemstärkende Küstenschutz.
How typical northern German maritime landscapes can be integrated into protection concepts of the responsible authorities and what additional functional protection through wave attenuation or independent adaptation such ecosystem-based approaches offer is being investigated in the project "Good Coast Lower Saxony". To this end, Real Labs are being set up on the North Sea and data collected over years to observe the dyke foreshore with its vegetation. In a further step, the field data will be used to map the natural areas in the laboratory and to test various system states on surrogate models in order to subsequently be able to formulate recommendations for action for coastal protection.
On the German North Sea coast, wide beaches and natural coastal dunes characterise the landscape and attract millions of tourists every year with their ecological diversity. The dunes form as a result of sand drifts, pile up several metres high and are colonised by numerous plant and animal species over time. In addition to their ecological importance, these soft coastal stretches also often fulfil an important function, as they protect the adjacent hinterland from flooding. However, both the habitat diversity and the protective effect in the event of a storm surge are massively endangered by the long-term consequences of climate change and the associated sea level rise.
For this reason, science is setting itself the goal of developing sustainably effective coastal protection for the affected regions, which at the same time also preserves the natural biodiversity in the habitats. The research project "Sand Coast St. Peter-Ording" is developing various concepts for a dune area in St. Peter-Ording in order to adapt the dunes to rising sea levels as close to nature as possible.
Experimental test facilities are of great importance in science in order to reproduce and understand complex physical processes from nature on a large scale. With the help of a wave machine, natural wave characteristics can be artificially generated in a long channel or in a wide basin. This allows both constructive coastal structures (e.g. dikes) and natural coastal landscapes (e.g. dunes) to be subjected to various wave and current loads.
In the "Sand Coast St. Peter-Ording" project, the dune chain to be investigated is being reproduced as a model (scale 1:10) in the wave channel in order to test its protective effect under characteristic water level and wave conditions. In an initial test phase, in addition to the current protection level of the dune, its protection potential under future increasing storm surge loads will also be simulated. With the help of numerous measurements, the morphological interaction between the dune and the attacking waves can be recorded and under which load variables certain failure mechanisms and probabilities occur. Based on these findings, several ecosystem-compatible protection concepts are to be designed and tested in a second test phase, which provide for targeted dune reinforcement with natural, near-natural (e.g. vegetation) or soft (e.g. sand stabilisation) measures.
These and many other exciting topics also await you in the study of Civil Engineering. Building with Nature thus takes place in a diverse and challenging area between Biology, Physics, Engineering and many other disciplines, and will continue to require motivated and practice-oriented students in the future to shape our environment and infrastructure.
Interest aroused? On this page, the Leichtweiß Institute for Hydraulic Engineering and Water Resource at the TU Braunschweig gives you a small insight - If you are interested, you can contact the staff of the Leichtweiß-Institute or Faculty III at any time!