Understanding systems: from river basin to coastal zones
Managers of water systems like rivers, estuaries and coastal zones must consider numerous factors, such as water quality, navigability and biodiversity. Optimising the management of a water system or tackling unexpected problems crucially depend on knowing how an area functions. Deltares helps water managers and government authorities to map out these aquatic ecosystems. We conduct research to determine the presence, behaviour and effect of particles (such as sand and silt), chemical substances (nutrients and toxicants) and organisms. By looking at the interaction between the different factors, we provide water management authorities and legislators with options – sometimes unexpected – for solutions or policies.
The knowledge about the ecosystems can be used in different areas such as:
- the analysis of specific problems such as polluted water, silting or the spread of algal blooms;
- the availability of sediment for coastal defences, river development, sand/clay extraction and nature;
- defining standards for laws and regulations, and establishing frameworks for policy relating to soil management, nature and water quality;
- identifying the possible impact of human activities – such as offshore dredging – in a particular area. Deltares can also contribute to Environmental Impact Assessments.
These applications require different types of research, from large-scale to detailed. We use models to calculate and predict the behaviour of particles and chemical substances. In each situation, Deltares looks at what is needed to help water management and government authorities.
- We appraise and assess the morphology, water quality and ecology of particular areas, making it possible to provide sound arguments to show why the status of an area is adequate for the functions fulfilled by the water system such as tourism, shipping, water extraction or agriculture.
- The morphodynamics research line focuses on mapping out and predicting changes in the subsurface over the course of time. The transport of sediment particles – the sediment balance – affects landscape development, flood risk management and ecology. How can these sediment dynamics be used to improve the water system?
- Nutrients and toxicants are transported by, for example in the surface waters or groundwater or bound to suspended sediment. This research line investigates the transport and settlement of these substances at a river basin scale. We continuously improve our fate and transport models resulting in a clear picture of the impact.
- In addition to the long-term morphological changes, we also look at the details of sediment behaviour. Silt is an important factor in ecosystem functioning but how it behaves depends on several factors. We look at which elements – such as flow rate, salinity, and the weight of the particles – affect sedimentation, and how.
- A detailed understanding of processes at natural interfaces can tell us a lot about the causes of, and possible solutions to, specific problems in river basins or coastal zones. For example, what happens when phosphates in groundwater enter surface waters? How does the transition from fresh to salt water in estuaries affect water quality and ecology?
From monitoring to solution
This programme is closely linked to the instruments developed in the monitoring and models programme and to the programmes for selecting and implementing solutions : Solutions for impacted environments and nature-based engineering .