The impact of high sea-level rise (1-5 m) on mainport hinterland transport networks

Abstract

Climate change & sea-level rise
It is well-known that the Netherlands is susceptible for sea-level rise. Half of the country is situated below sea level and in an estuary. Previous measures of the Dutch against the threat of inundation have resulted in the closure of estuary branches, decrease in the length of primal flood defences and the world-renowned Delta Works. The Nieuwe Waterweg is kept open for economic reasons, in order to provide unhindered access to the port of Rotterdam, the largest deep sea port in Europe. However, the rise in sea level poses a threat to the accessibility of the port.

Sea-level rise adaptation scenarios for the Netherlands
There are various scenarios conceivable for the Netherlands to adapt to sea-level rise. The main scenarios are 'Open protection', 'Closed protection', 'Seaward' and a 'Retreat' scenario. Each scenario brings its own set of challenges and benefits. There are many strategies to implement these scenarios for future landscape and sea-level rise adaptations.


Currently, there are around ~180 sea-level rise adaptation strategies for the Netherlands, as collected by Deltares. Only a handful actually include the effects on modality networks, port activities and shipping. Furthermore, all strategies use the same method which uses multiple models and has a lead time which stretches over multiple weeks to determine the effects on waterborne supply chains. Moreover, this method is not compatible for the retreat scenario. This forms the knowledge gap of the thesis.


Proposed method & model
This thesis therefore sets out to mitigate that gap by developing a first-order method to quantify the consequences of large sea-level rise projections, landscape changes and hinterland modality network changes of a deep sea port and to provide the results in a comprehensive manner.

Therefore, we propose and create a method and a model to quantify the consequences on spatial sea-level rise adaptation strategies on hinterland container port competition, by enforcing modality network changes and being able to easily adjust boundary conditions of the model. This thesis brings forth the method and model and subsequently applies it to the Netherlands and the port of Rotterdam as a case study. The ports of Antwerp and Hamburg are additionally taken into account to model the port competition. The method and model can account for any number of deep sea ports and countries.

Conclusions & recommendations

- This thesis shows that currently, the majority of the sea-level rise adaptation strategies do not take their effects on waterborne transport and port activities into account. Furthermore, the strategies that do currently all use the same method, which cannot account for a retreat scenario. Furthermore, this existing method uses four models which results in a total cycle time in the order of weeks. These existing models cannot account for landscape or network changes.

- The proposed method shows that current port operations for Rotterdam are no longer viable at +3 m sea-level rise and a retreat scenario. Two options for are suggested for the port of Rotterdam: relocate the port to the new coastline or transform the current port in a deep sea terminal in combination with inland terminals at the new coastline.
\item The proposed method further shows that Belgium and Germany experience less inundation at +3 sea-level rise and a retreat scenario. Moreover, the ports of Hamburg and Antwerp are less susceptible to the inundation and do not have to resort to the extreme measures as the port of Rotterdam.
\item The model shows that by locating the port more inland and in close proximity to (current) modality networks, the competitive position of the port of Rotterdam increases, whilst losing the advantages the port presently enjoys over Antwerp and Hamburg, as the modalities are now closer to the hinterland destinations. This is most notable for the road modality.
\item Following the model, it can be concluded that new port locations have to be chosen with care as the results suggest a large decrease of hinterland areas for two locations (-51% and -88%), whilst the (other) two locations only show a slight increase in hinterland port areas (+3% and +16%). The model suggests that the most promising new port location is Tiel.
- The proposed model only accounts for the container commodity, other commodities, such as dry bulk and liquid bulk, could give different results and it is therefore recommended that further research is done based on the other commodities. 
- It is further recommended to improve the model by adding a common starting point, China for example. Currently, the model starts at the quay, when the containers are unloaded from the deep sea vessels. This would give the option to add (dis)advantages of ports, such as increased relative distances, a tidal window, or container dwell times.