Water levels in the river Meuse drop during periods of low river discharges, making it unnavigable for shipping. To maintain navigability in the Dutch part of the river Meuse, seven weir complexes were constructed in the river. These complexes regulate the river and maintain target water levels to allow for shipping throughout the entire year. The complexes were constructed in the early 20th century and are all reaching the end of their technical lifetime. Therefore, they require replacement or renovation. This provides the opportunity to explore ecosystem restoration at these complexes.
The seven weir complexes are located at Borgharen, Linne, Roermond, Belfeld, Sambeek, Grave, and Lith. Each complex consists of weirs, locks, and fish ladders. These complexes act as barriers to fish migration, the river’s sediment transport, and reduce the lotic habitats in the river (in Dutch: ‘Stromende habitats’). The reduction of lotic habitats leads to a decline in species that depend on these environments.
The objective of this report is to study the possibility of creating an optimized ecological route at conceptual level for the weir complexes in the Dutch part of the river Meuse to create environmental conditions for the formation of lotic habitats. This optimized ecological route is referred to as an ecological channel. The channel was designed to support specific endangered river species, referred to as the target river species.
The channel was initially designed for weir complex Sambeek, which serves as the case study location. This complex was selected as it has the most available space, which provides more flexibility for the channel’s design. Subsequently, an assessment was conducted to determine whether the channel could be applied to the other complex locations. To form lotic habitats, the channel must meet certain environmental conditions that are based on the needs of the target river species. These conditions must be achieved during the critical reproductive months of these species. The environmental conditions primarily consist of varying flow conditions, which are achieved by varying inflow rates, indicating the need of an intake structure.
The ecological channel was designed through an iterative process, as its dimensions and flow conditions have interdependent relationships. These parameters had to be iteratively adjusted until a suitable combination was found that met the required conditions. To streamline the process and reduce the number of possible combinations, the design of the channel’s intake structure and the channel’s dimensions were done separately.
The final ecological channel design includes an intake structure consisting of a flap gate and vertical-slot fish passage. An impression of the final channel design at weir complex Sambeek is shown in the figure on the following page. The channel design meets the required environmental conditions for habitat formation for river discharges up to 500 m3/s for weir complex Sambeek, Linne, Roermond, and Grave, and for discharges up to 250 m3/s at complex Borgharen, Belfeld, and Lith. Both discharge ranges include the critical reproductive months of the target river species, as was required. The final design shows that the required environmental conditions for lotic habitat formation can be achieved at the weir complexes in the Dutch part of river Meuse, potentially leading to an increase in the populations of the target river species.
The channel design may not accurately represent reality due to uncertainties in the estimations and limitations of the channel’s boundary conditions, available space, and simplifications of its hydraulic processes. In addition, even if the required environmental conditions are achieved, it does not guarantee that the river species will utilize the channel, as their behaviours can be unpredictable, and their response may not be as anticipated. To develop a more realistic and detailed design, it is recommended to construct a hydraulic model and conduct further research on the behaviours of the river species.

The coastal area of the Murcia region in Spain experiences more frequent and more intense flash floods caused by inland heavy rainfall due to climate change. This results in high water levels in towns and cities, leading to risk of loss of life and many financial damages. Currently the region is vulnerable, because there are no hydraulic structures that regulate the flow safely downstream towards the coastline. Instead, at this moment the current channels are inadequate dry rivers. To reduce the risk of flooding, the objective of this design was to design a flood abatement control zone (ZAC). This design followed the design approach for Hydraulic Engineering.

A ZAC consists of a series of dikes that enclose separate reservoirs that are able to temporarily store water. This dampens the peak discharge of the flash flood, which reduces the flood risk of the downstream area. The peak reduction is the main function. The water that is stored is being discharged with a delay, spreading an acceptable discharge over a longer time to discharge the same rainfall event volume.

The first step of the design was to define the system of the ZAC. The ZAC was combined with the creation of an up- and downstream channel with short lengths to fit the structure into the environment. Its design life was set at 50 years, corresponding to a design rainfall event of once per 474 years. To design this structure, it was important to determine the maximum rainfall event discharge and the existing maximum discharge capacity without floods occurring downstream. These 2 factors, together with soil properties and land boundaries, acted as boundary conditions to the system.


In step 2, two locations were considered as potential construction location, both indicated by the client Universidad Polytechnica de Cartagena (UPCT). By applying a multi-criteria analysis (MCA) based on predominantly the water inflow, potential storage area, close company buildings and houses, the more upstream location was chosen.

Step 3: in order to design an adequate ZAC, a model was required to create the before-and-after-construction situation. A hydrological 2D-flow model was created in HEC-RAS. This was closely tied to functional design and design steps were taken iteratively. The 2D-model was able to compute flow in longitudinal and lateral direction, which is strongly needed in a flooded terrain. The most important design parameters to test in the model were the culvert-spillway-structure and the number of reservoirs. The model was validated qualitatively by flood maps from Centro de Descargas del CNIG.

Then, the functional design of the ZAC was done in step 4. The ZAC was placed partially dug into the soil upstream, and partly sticking out of the soil downstream. Upon iteration, it was decided to create 5 reservoirs, because of costs and a smaller marginal peak reduction effect of extra reservoirs. The ZAC is created in combination with a downstream funnel, downstream outflow channel and upstream channel. This means that the reservoirs are enclosed by 2 side dikes and 6 lateral dikes.

Then, detailed design in step 5 followed. The culvert-spillway structure was designed. The aim of this structure is to let water through the reservoirs without overflowing and therefore damaging the dikes. The structure consists of a culvert, spillway and retaining walls. For each element an MCA was set-up to determine the optimal shape, followed by choosing the design alternative. The design is a trapezoidal spillway, an arched culvert and a retaining wall.

With the optimal design, a conceptual design is constructed. In this conceptual design, the reinforced concrete dimensions and governing load combinations are determined. From this, the strength of the ZAC structure is evaluated in the finite element method program DIANA.

Finally, the final design was created. The conclusion is that the combination of structural elements that have been modelled in the system satisfies the aim to reduce the design rainfall event flood wave enough to avoid flood risk to the downstream areas of Murcia. The main uncertainties are the scaling of the data of the design rainfall event and the used soil characteristics. Further research could look into quantitative validation of the 2D-flow model, the implementation of sediment transport in the model and into optimizing bed protection downstream of the ZAC.