Riparian ecosystems are crucial for maintaining ecological balance in riverine landscapes, offering diverse habitats, regulating water quality, and preventing soil erosion. However, these ecosystems are vulnerable to slope instability, leading to detrimental effects such as land loss, habitat destruction, and increased sedimentation in water bodies. In the Netherlands, the banks of waterways are typically protected using various materials, some of which emit significant carbon during production. To meet environmental goals such as the Paris Agreement (2022), there is a need for alternative bank protection structures that utilise natural materials.

Root reinforcement, which refers to the ability of plant roots to enhance soil strength and stability, plays a crucial role in assessing slope stability. The presence of roots influences soil strength through hydrological and mechanical effects. Existing methods for quantifying root reinforcement involve mechanical models or time-consuming in-situ measurements using large equipment. Therefore, the corkscrew extraction method has been developed as a quicker, lighter, and simpler approach to measure shear strength in root-reinforced soil. Previous studies have demonstrated the potential of this method for quantifying root reinforcement in field conditions, providing rapid data collection on shear strength at different depths and steep slopes. Throughout the thesis, a corkscrew set-up, inspired from Meijer et al. (2018) was used to assess root reinforcement in riparian environments. Also, it was determined whether this technique is applicable in riparian conditions.

The corkscrew device consists of a garden corkscrew weeder, a tripod with a ratchet winch, a steel cable, a load cell, and a draw wire sensor. The corkscrew is maunally rotated into the soil, and the load and displacement are measured during extraction. The force-displacement curves are analysed to determine rooted soil parameters.

The measurements were conducted at two locations in the Netherlands: the Botanical Garden of the TU Delft in Delft and a testing site in Middenmeer. The Delft location had fields with reed plants (Phragmites australis) and willow trees (Salix fragilis and Salix purpurea), while the Middenmeer site was planted with hawthorns (Crataegus laevigata). Corkscrew extractions produce force-displacement curves, which exhibit different patterns depending on the root content (root area ratio).

The study finds that the corkscrew method is a promising technique for measuring root reinforcement in challenging terrains like riparian areas. It offers advantages in terms of time efficiency, field applicability, and non-destructiveness compared to complex and destructive methods. However, challenges related to root recovery and the limited testing depth need to be addressed through further research.

The thesis also examined root and strength parameters related to root reinforcement. While root biomass provides information about the quantity of roots, it may not accurately quantify root reinforcement. The root area ratio was found to affect soil behaviour and showed correlations with strength parameters for certain selected species. However, other factors such as moisture content, the soil conditions and root diameter could also influence the relationship between root area ratio and shear strength. The force-displacement graphs obtained from corkscrew measurements highlight the significant influence of roots crossing the shear surface on soil behaviour by comparing the pattern of the curves. Also, root breakages are identified as sudden drops in force displacement graphs.

The presence of roots mobilising at higher displacements than the peak strength of bare soil is crucial for slope stability. The combination of species might provide the best reinforcement effect for stability owing to difference in root paterns spatially and with depth. ... Read more

Over the last years, the urge to reduce the world’s air pollutants is rapidly growing. New possibilities in order to replace fossil fuels have been explored and one of them is the usage of green hydrogen. The Argentinian, North Patagonian, province of Río Negro, has a great potential to generate green hydrogen on a large scale, due to the available natural resources. Therefore, the province is ambitious to contribute in the developing worldwide sustainable energy market by producing and exporting green hydrogen.
Argentina is located at a large distance from the expected green hydrogen sales market in Europe and Asia. In order to reach competitiveness with respect to other future hydrogen ports, the use of a Free-Trade Zone (FTZ) is considered. This is a delimited territory within a country in which tax benefits can be enjoyed. The Province of Río Negro is considering three different locations for a potential green hydrogen export port:

- Punta Colorada Muelle, is an old iron ore export port that is out of operation since 2016. It is located within a FTZ. The deteriorated dry bulk jetty could potentially be reused by accommodating the liquid bulk loading infrastructure.

- Punta Colorada South, is a location roughly one kilometre south of old iron ore export port and is also located within a FTZ.

- Puerto Lobos, is located on the border of the provinces of Río Negro and Chubut. It has potentially favourable bathymetric and hydrodynamic characteristics.

The following main research question is formed:
”Which location between Punta Colorada Muelle, Punta Colorada South and Puerto Lobos is the most suitable for a potential hydrogen export port in Río Negro?”
A conceptual qualitative Multi-Criteria Analysis is executed to compare the locations. In order to complete this analysis, firstly the hydrogen export port requirements and criteria are defined. Subsequently, primary and secondary data is collected. The primary data consists out of fieldwork surveys, including a topographic analysis, a hydraulic analysis and a structural analysis. The structural analysis is completed solely on the existing jetty at Punta Colorada Muelle, in order to create an understanding of the current state of the jetty. Furthermore, interviews are conducted with the director of the Maritime and Fluvial Research Center (CIEMF), the executive director of investment agency of the Government of Río Negro, and an ex-employee of the previous mining company at Punta Colorada Muelle. Secondary data on all locations is gathered through literature studies and presented documents from stakeholders.

With data from the field survey several detailed maps are made. A bathymetry map shows the sea bed profile from Punta Colorada Muelle until Punta Pórfido. A topographic map shows the ground level elevation for Punta Colorada Muelle. An interactive map of the jetty is made which contains all the gathered photographs of the structural components and indicates their level of corrosiveness. Next to that the stakeholders are displayed in a power-interest diagram.

Due to the limited information and the quality of the information that was gathered at Puerto Lobos no fair comparison between the locations can be made. Both locations at Punta Colorada have potential to construct a green hydrogen export port. The jetty at Punta Colorada Muelle has the potential to be used in the short-term if it is restored. Punta Colorada South has the advantage that potential future port operations will not depend on dated infrastructure. Next tot that there is no interference with the iron ore port authority. Puerto Lobos has the disadvantage that there is no FTZ and that is situated adjecent to a marine protected area.

To properly compare all three locations, bathymetric and aerial surveys that were completed at the Punta Colorada locations will need to be repeated at Puerto Lobos. To create a more definitive conclusion on any location, additional research like a CPT and an in depth analysis of the structural capacity of the jetty is required.

From the bathymetric surveys another potentially interesting location was found in Punto Pórfido. It is recommended this location is researched further.

Three alternative scenarios for phasing the port construction and operation are presented. These scenarios differ in permanent, temporary or no use of the current jetty at all. ... Read more