The impact of low river discharge levels on seaport terminal processes

Abstract

The increasing severity of river drought poses a potential threat to the operations of ports using rivers as hinterland connections. River droughts have impacted navigation in various rivers worldwide, including the Rhine river where instances of low water levels in 2018 and 2022 caused disruptions in navigation. As a consequence, inland vessels were forced to reduce their cargo loads. Seaport terminals that serve as crucial links between sea vessels and inland vessels may be impacted by changes in fleet composition, thereby affecting a terminal's cargo handling operations and storage. However, there is a lack of research quantifying the effects of low river levels on seaport processes and determining suitable methods to assess this impact using vessel movement data.

To address this research gap, this study aims to quantify the impact of low river levels on seaport processes by focusing on the EMO dry bulk terminal within the Port of Rotterdam as a case study. Given the connection between this port and the Rhine, which is known for its vulnerability to drought and serves as a vital route for inland navigation, the analysis begins by examining the impact of reduced river discharge on the dry bulk fleet sailing from Rotterdam to Germany utilising Information and Tracking System for Shipping (IVS) data. Additionally, Automatic Identification System (AIS) data is employed to assess the service time, the number of vessels and the berth occupancy within the terminal to quantify the impact of low river discharge on the cargo handling process within the terminal. Specifically investigating the effects on vessels being loaded and bound to the hinterland and those being unloaded after arriving from the sea. Finally, the study analyses the impact on the storage capacity of the EMO terminal using monthly cargo data provided by the terminal, by studying the balance between the amount of cargo being unloaded and loaded.

The findings show that vessels sailing along the Rhine are required to reduce their load as discharge decreases, leading to an increased number of vessels. However, this compensation by more vessels does not fully offset the load losses, resulting in a decrease in the total load carried per day when discharge decreases. Consequently, more vessels arrive at the EMO loading berths during low discharge periods to compensate for the reduced load and therefore loading time for vessels at these berths is shortened. Due to the increased vessel arrivals, the berth occupancy at the loading berths increases to a maximum of 65%. On the contrary, the berth occupancy at the unloading berths remains unaffected. Cargo flow analysis shows that the lowest cargo loading into inland vessels occurs during months without low discharge, rather than during the months with the lowest discharge. Additionally, the share of rail transport increases during low discharge months but remains below maximum capacity, indicating sufficient slack to handle all cargo. The stockpile analysis reveals a small surplus during low discharge months, although not as significant as in months with normal discharge levels.

Overall, the findings indicate that the large size of the EMO terminal allows it to withstand the impacts of past periods of low river discharge. As the loading berth's occupancy is not at its maximum capacity and the unloading berths remain unaffected, there is sufficient slack to accommodate additional vessels. Accordingly, adequate vessels are loaded to transport cargo to the hinterland, ensuring no impact on the stockpile and thus maintaining the storage operations at the EMO terminal without disruption.

While this research provides valuable insights, it is important to acknowledge that terminals of varying sizes or handling different cargo types may experience different impacts and should be subject to further investigation. Additionally, the limited availability of AIS and cargo data, with only one year of extreme drought (2022) for analysis, prevents drawing definitive trends and making long-term assumptions for future scenarios. Nevertheless, this study's methodology can be adopted in related studies to analyse more terminals and gain further insights.