Graduation of Susanne Taekema

30 August 2017 12:30 - Location: Room 3.98 , Faculty of Civil Engineering and Geosciences

Climate Change and Waal Canalization”| Professor of graduation: Prof. Ir. T. Vellinga, supervisors: Ir. H.J. Verheij (TU Delft), Ir. W.F. Molenaar (TU Delft), Dr. Ir. J.C.M. van Dorsser (TU Delft).

The River Waal is one of the most important shipping routes in the Netherlands. The river fulfills several functions whereof inland shipping is one with high economic value. To maintain the functions of the river, but also to protect the river area, human interventions such as river training structures are applied to regulate theriver. Climate change may lead to other circumstances and river characteristics which could have a negative impact on the functions of the river. River canalization is an example of a major regulating measure, that is often applied to create sufficient and more constant water levels which is favorable for inland shipping. However, river canalization has a lot of ‘side’ effects that can have major impact. Therefore, the consequences of canalization must be investigated carefully.

This research is about the effects by climate change on the inland shipping sector of low discharges in the River Waal. Two different situations are investigated, one without any measure and one with canalization of the river. These two situations are compared with a zero variant where no navigation restrictions occur and therefore a so- called reference situation is also investigated. The focus is on the direct costs for the inland shipping sector due to navigation restrictions caused by insufficient water depth and canalization. Besides, the more integral picture is taken into account by the total costs due to canalization, which consist of the shipping costs due to canalization and the weir- and lock complex costs (from now on referred to as WLC costs). Other external effects, such as the reliability of inland shipping and modal split to other transport modes are not considered in this comparison study.

Canalization is defined as a plausible measure for improving the navigability of the River Waal when the shipping costs in case of canalization are lower than the shipping costs due to climate change without any measure. However, the more integral picture shows whether canalization is a feasible measure. When the total shipping costs due to canalization are lower than the shipping costs due to climate change without measure, canalization can be marked as feasible.

The geographical area that is taken into account is the physical river system from the German border (rkm 860) to the port of Rotterdam (rkm 1000). The fixed layer at Nijmegen (rkm 883 – rkm 885) is the most critical point of the River Waal with regard to the navigable depth. The important developments for this research are climate change, economic growth and the future fleet composition. Various possible future situations are considered by taking different scenarios into account. For climate, these are the WH,dry, WH, GH, GL and WL scenarios. For economic growth, the WLO scenarios are used.  For the characteristics of the future fleet only scaling is considered and the composition is equal to the current fleet. The consequences for inland shipping are investigated for two time horizons, namely at the years 2050 and 2085. 

For studying the effects of the different developments on the inland shipping sector an effect model is developed, validated and used. This model requires the following inputs: the normative depth each day during a year, the characteristics of the normative vessel and the total freight transported by inland shipping. Using this information, the model is calculating the load factor for each day and this results in the required number of loaded trips per year for transporting the amount of cargo. Subsequently, the total shipping costs in case of navigation restrictions can be calculated and is given as output of the model. Comparing these shipping costs with the total shipping costs of the reference situation, the extra shipping (or damage) costs due to navigation restrictions can be computed.

The shipping costs in case of canalization are determined for the most optimal option of canalization, which is defined as the option with the lowest total costs due to canalization. The optimization of the canalization is fully determined by the number and the dimensions of the WLC. The relation between the shipping costs and the water level difference over the weir (head) in combination with the relation between the WLC costs and the water level difference affect the optimal option. Applying a lower head leads to increasing shipping cost due to more navigation restrictions and decreasing WLC costs due to lower forces on the structure. For each scenario, there is a different optimum and therefore only for one (representative) situation the optimal option of canalization is investigated. Subsequently, this optimal option is used for investigating the consequences of several scenarios. The representative situation is the annual discharge distribution from 2003 in combination with the high economic scenario and the normative vessel for 2050, because it is expected that the discharge distribution from 2003 will occur annually around 2050.

However, the shipping costs are determined for a specific year, while the WLC costs are total costs. To be able to compare both costs with each other, the WLC costs are translated into annual WLC costs by using the equivalent annual cost method. The equivalent annual costs are the annual rental payments sufficient to cover the present value of all costs of owning and operating. Because the shipping costs are determined for one specific year, it is more convenient to use this equivalent annual cost method than doing a common net present value calculation. 

Based on the total head over the entire route it is determined that the area of interest, relating to the number of WLCs, is from one to three WLCs. For this area of interest the most optimal option for Waal canalization is investigated. Taking the total cost into account, it is found that it is more attractive to permit some navigation restrictions by applying a smaller water level difference over the weir . Furthermore, one WLC with a head of 8.0 meter is determined as the most optimal option for canalization of the River Waal. For this situation, the shipping costs are lowered from about 60 million Euro to about 7.5 million Euro. Looking at the integral picture, the total costs of canalization are lower in case of canalization and therefore canalization is an attractive measure.

The consequences in case of several scenarios for this canalization option are investigated to get insight in the range of possible outcomes. The scenario analysis shows that the shipping costs for all scenario combinations are lower in case of canalization than in case without any measure. Looking to the more integral picture, the total costs due to canalization are only in case of the most extreme climate scenario lower than the shipping costs in case without any measure. For all other scenarios, the total costs due to canalization are much higher. The results of all scenario combinations are included in the figures alongside to here.

 

It has been noted that the WLC costs are the biggest part of the total costs due to canalization. Therefore, the WLC costs have a much greater effect than the shipping costs on the total costs of canalization and therefore on the feasibility of canalization. In addition, the total WLC costs are about €1200 million and this might be a bit high for one WLC. Therefore, it is desirable to improve the accuracy of the WLC costs to obtain more reliable outcomes and insight in the feasibility of canalization.  However, no conceptual design is available and therefore it is hard to improve the WLC costs and to quantify the feasibility of canalization. To give an indication of the expected feasibility, the sensitivity of the WLC costs is investigated.

During the sensitivity analysis, the total costs due to canalization for various WLC costs are investigated. The result is shown in the figure alongside to here. For total WLC costs below 400 million Euro the feasibility of Waal canalization is quite high, which means that for many scenario combinations the costs due to canalization are lower than the costs in case without measure. However, for WLC costs between 400 million Euro and 900 million Euro the feasibility decreases to 20%.

 

Summarizing: canalization can be marked as a plausible measure to improve the navigability of the River Waal for inland shipping, because the shipping costs in case of canalization are lower than in case without any measure. Taking the more integral picture inclusive construction, maintenance and operational costs of a WLC into account, it is hard to indicate whether canalization is also a feasible measure because the WLC costs are very uncertain and these have a major effect. Therefore, an indication of the expected feasibility for various WLC costs is given. For WLC costs up to 600 million Euro the feasibility is more than 50% in 2085. For higher values of the WLC costs, the feasibility decreases to 20% and finally to 0%. It is expected that 1000 million Euro is quite large for one complex and therefore it is assumed that a feasibility of at least 20% is reached.

This research has shown the impact of climate change and Waal canalization on the navigability and therefore on the direct costs for inland shipping. Because the River Waal is the main shipping route between Rotterdam and Germany and a lot of freight is transported by inland navigation, the economic importance is high. A worse navigability can also have impact on other transport modes if modal shift takes place. Therefore, the impact of a worse river navigability can be large and, therefore, it is useful to investigate this. When the overall effects of a worse navigability are known, an appropriate solution can be found and policy implications can be made. At this stage, it is too early to conclude whether canalization is that suitable measure. However, it can be concluded that inland shipping experience such restrictions that a measure must most likely be taken. Therefore, it is recommended to investigate several possible measures that avoid navigation restrictions. In combination with research to the overall effects of a worse river navigability, more reliable policy implications can be made.

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