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Optimising coastal structures with numerical modelling
The joint industry project (JIP) Coastal Foam focuses on the development of numerical tools to predict the stability of various components of coastal structures, and particularly on the open source CFD-toolbox OpenFoam. One of the studies looked at open filters in which rock material is placed on top of a sand core. Another area studied was slamming loads from breaking waves on crest wall elements.
Monitoring the quality of railway tracks from space
Subsidence can play a key role in the performance, serviceability and safety of engineering works such as railway embankments. Research by Deltares in 2007 indicated that 40% of the maintenance costs for railways in the Netherlands are linked to preserving the geometry of the railway track. Deltares developed a predictive settlement model for railway embankments built on soft soils. The main achievement of this project is the stochastic prediction of secondary settlement using satellite data and subsoil data. This prediction will improve the assessment of the quality of railway tracks in the long term and help to rationalise existing monitoring campaigns.
Bather Safety App
Deltares hosts a mobile phone application that displays forecasts of sea currents and beach widths around the Sand Motor (Delfland Coast, the Netherlands). The information is consulted by the lifeguards responsible for monitoring bather safety at the Sand Motor. It allows them to anticipate potentially dangerous situations on the beach and in the shallow waters such as rip currents. Precautionary measures can be taken to reduce the risks for visitors to the beach.
The added value of passive sampling in the monitoring of organic pollutants
Good and effective monitoring of water quality is key to determining whether, and where, measures should be taken to improve water quality. Monitoring for organic pollutants can be performed with passive sampling. A sampler with sorption material is exposed to water for several weeks or months. During the exposure, organic pollutants are sampled by diffusion from the water, resulting in a time-integrated average concentration based on large sampled volumes. In recent years, Deltares has further developed the technique and applications in a range of water types such as sewage water, surface water and groundwater.
A fresh look at effective river restoration
The assessment of the First River Basin Management Plans conducted in the context of the Water Framework Directive (WFD) indicated that 40% of European rivers are affected by hydromorphological pressures that are caused predominantly by hydropower, navigation, agriculture, flood protection and urban development. A consortium of 26 partners coordinated by Deltares was therefore established to generate substantial output as part of the REFORM project (REstoring rivers FOR effective catchment Management) to support the implementation of the Water Framework Directive.
Quantifying the long-term effects of human interventions on estuarine sediment concentrations
Many estuaries worldwide have been modified in recent decades and centuries, for example through land reclamation or to allow ever larger ships to access inland waterways. These human interventions often lead to higher suspended sediment concentrations (SSC), which reduce visibility and lead to a decline in primary production at the base of the ecological food chain. One estuary affected in this way is the Ems Estuary on the Dutch-German border. Deltares has quantified historical changes in SSC associated with human interventions and advised on mitigating measures.
Recovery of Adelaide’s seagrass meadows
Seagrass has been disappearing from Adelaide’s coastal waters in the Gulf St Vincent, South Australia since the 1950s. The Adelaide Coastal Waters Study concluded in 2007 that the seagrass decline was caused by discharges of treated sewage, rivers and storm water, which reduce water transparency and further the excessive growth of “epiphytes” on the seagrass leaves. Both phenomena reduce the amount of sunlight penetrating to the seagrass leaves and subsequently kill the seagrass. At that time, however, it was not clear when, where, and by how much these discharges would need to be reduced to create the conditions required for recovery of the seagrass meadows. The South Australian Water Corporation (SA Water) commissioned Deltares to jointly develop coastal modelling capabilities that would help to answer these questions. With Delft3D as the main “engine”, SA Water, Deltares and DAMCO Consulting (Perth, West Australia) built the Adelaide Receiving Environment Model (AREM).
Drones monitoring vegetation in watercourses
Regional water authorities usually have limited information and knowledge about the vegetation present in their watercourses. An innovative monitoring technique was developed that uses a full-spectrum camera on a drone. The technique was tested in the River Experiment Center of the South Korean Institute for Civil Engineering and Building Technology (KICT) in Andong and in two Dutch streams.
Human interventions and climate change on the West African sand river
The West African coast consists of a narrow low-lying coastal strip maintained by sediment from rivers that is transported along the coast by waves and currents: a “sand river”. Today, however, much of the fluvial sand is retained behind river dams and the flow is interrupted at several locations by jetties. The sandy coastal barrier is therefore eroding almost everywhere. The situation is already critical and it is likely to worsen in the future due to climate change. This study set up a quantitative and consistent large-scale sediment budget study using a unique numerical modelling framework for the Ivory Coast, Ghana, Togo and Benin. The numerical modelling framework was based on Delft3D and UNIBEST-CL+.
Effect of dam-gate operation on sediment flushing
A new approach has been developed to investigate different approaches to operating dam gates in the Funagira dam in Japan. This approach consists of quasi-3D-modelling coupled with the real-time control toolbox (RTC), resulting in more efficient reservoir flushing and more sediment transport to the downstream reach.