Measurement and monitoring the delta system

Our experts have a range of research options at their disposal: laboratories, computer models, large test halls (facilities), field trials and innovative measurement and monitoring methods. We also develop innovative measurement and monitoring methods. We have a wide-ranging knowledge network that we can use to search for solutions. That makes the difference when it comes to delivering outcomes that can be applied in practice.

How we increase our knowledge

How we increase our knowledge

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The subsurface

Our research area is where water, the subsurface and sediment interact. The focus in this drawing is on the subsurface, an important supplier of ecosystem services, but also an important basis below our feet. We live and work on it. Increasingly, we will have to make deliberate decisions about it.


Deltares has a geotechnical and a physical-chemical-biological laboratory where we investigate the specific properties of the subsurface, sediment and soil health.

Deltares zooms in and out

Zooming in and out makes it possible to include every piece of the puzzle while guarding coherence so that issues are addressed integrally, from a systems approach.


Where and why do we measure?

Fresh-Salt boundary



Where can we find enough suitable sand for construction activities or replenishment, how can we sustainably manage these stocks, what are good places for other offshore functions such as nature? What are the effects of our offshore activities in these areas? In addition to geophysical data, we also draw on borings that provide geological information.


Wind turbines

Efficient foundations that are as sustainable possible are needed for the turbines. We conduct extensive tests in our facilities to model the processes relating to currents and the seabed. We study ways to protect foundations against scouring. The composition of the subsurface also plays an important role here. The installation and presence of wind turbines affect local biodiversity. Working with others, we look for and test solutions, and measure factors such as currents, scour and vibration. In our laboratories, we look at the effects of anti-corrosion treatment on the environment. And we conduct studies to see whether the burial depth of power cables with fibre optics can be monitored to prevent damage. 


Urban areas

Water shortages can cause effects such as the shrinking and swelling of clay, and damage to houses with shallow foundations or wooden piles. By measuring groundwater levels, deformations and/or crack widths, we can learn about the effects of climate change on towns and cities. With meters to measure crack width and photogrammetry, this work can be done over longer periods of time and remotely. We track how damage occurs and whether the chosen solutions work. Quay walls on canals in inner cities are often more than 100 years old, exceeding their technical lifespan. But do we really need to replace them all? Information from measurements of quay deformation, groundwater levels and the locality allows us to validate models and therefore to prevent unnecessary replacement or to make new construction work more effective. In the busy urban environment, smart measurement and monitoring allow us to map the subsurface and processes there while keeping disruption at the street level to a minimum.


Rural areas

We study the composition of the subsurface, in some cases very locally with borings or with extensometers. As a result, we now know that, for example, where there is land subsidence the soil sometimes rebounds. We also measure on larger scales with non-destructive geophysical methods. For example, electromagnetic measurements from drones and helicopters efficiently identify weak spots around dikes and the presence of saline groundwater. 

More information

Land Subsidence


CO2 and other greenhouse gases

Land subsidence in rural areas is often the result of oxidation. Peat exposed to oxygen releases CO₂. We measure this in the field on a small scale with a Micro-portable greenhouse gas analyzer or with Eddy Covariance for a larger area. This monitoring is important to determine whether the measures to counteract land subsidence also result in a reduction of carbon emissions. 

More information

Land subsidence



With borehole measurements, we can validate fresh-salt levels in models. In this way, we can see where fresh water can be stored. On the provincial scale, we do that from a helicopter with electromagnetic equipment. We use monitoring wells to determine the link between groundwater levels and climate change in order to work on solutions in good time. The validation of our models ultimately results in maps or dashboards that allow management authorities to take action. Measurements from other sources such as environmental services can also be modelled. 


Soil health

A subsurface with soil life is important, not only for the ecosystem but also to allow enough water to pass through and keep the soil moist. Clean soil means clean groundwater. Our research here ranges from counting earthworms to countering pollution with bacteria or other natural solutions. 



The subsurface plays an important role here. Scour deepens rivers and increases flow rates; dredging also has this effect. It also leads to lower summer levels and therefore lower groundwater levels behind the dikes. River widening – room for the river – is one of the natural solutions selected. Every decision has implications for the bed profile and the functions of the river. We are researching this area with stakeholders in living labs such as Sediment Rijnmond. Through monitoring, research in our facilities and modelling, as in the PRISMA study, dredging in ports is becoming more efficient and sustainable. 



The stability of dikes is important in a densely populated country like the Netherlands. This factor is studied in facilities and in full-scale trials in the field. During dike upgrade operations, successful innovations can be implemented immediately and regulations can be modified. We look at how piping and heaving can cause dike failures, as in the Hedwige polder and near Kampen. In this work, we use equipment such as pore pressure gauges, inclinometers and extensometers, and geophysical techniques such as ERT (Electrical Resistivity Tomography). But stability is also investigated on a large scale. We are currently mapping the subsurface of the entire dike system between Amsterdam and Enkhuizen.



Infrastructure is needed for life and work in the delta. With our knowledge partners, we research and advise on the construction, maintenance and resilience of infrastructure networks. We determine the influence of the subsurface and groundwater on the stability of infrastructure with a range of research and measurement techniques. For the purposes of safety and liveability, we measure and model vibrations caused by traffic and determine how fast trains can travel without causing problems. We use existing fibre-optic cables along the track as measuring instruments for this work. 

From the world of measurement and monitoring 

The picture for the future

Permanent connections

Connecting systems with each other will make it possible in the future to convert data into decision information remotely and at any time. We then check those decisions in the field.

Data, measurements (e.g. from satellites, robotics)

Self-learning models

Web viewer

Investing in new technology

We keep data available and usable, drawing on artificial intelligence and the latest computing methods. We invest in Deltares experts and in our measurement and monitoring facilities to meet the challenges.

FAIR data

Cloud computing

Machine learning

Integrating sustainable solutions

To preserve biodiversity and our health, it is important to integrate things like Nature-based Solutions. With measurement and monitoring, we can see how the applied solutions work and to what extent this makes the infrastructure in place more sustainable.

For example Sand Motor

For example using bacteria for soil pollution

For example Aquifer recharge


Communications are becoming ever more important. Science has to earn people’s trust these days. With measurement and monitoring, we can not only share knowledge and show the effects. Stakeholders themselves can also visualise their actions and efforts. That makes the result more inclusive.

Science communication

Citizen science

Coastal erosion in Senegal

For Saint Louis in Senegal, we worked on monitoring and modelling coastal erosion. In three major measurement campaigns, a lot of knowledge was acquired about the river waves, currents and discharge. We used the results to build models of the system. All the options to make the area safer can now be assessed using forecasts. Salinisation was also included. 

Saint-Louis, caught between two threats

Ganges basin

This basin is home to half of India’s population and it is an important source of water. To restore the water system (groundwater and surface water), and to prevent pollution and ecological degradation, a basin strategy is needed. Experts from a range of Deltares disciplines worked together here on surface water, groundwater, ecology, policy consultancy and communications. In addition to analysing the subsurface, groundwater flows and their quality, we needed to understand how groundwater interacted with the river and the irrigation canals. The river discharge, and therefore the groundwater system, is changing rapidly due to climate change. Discussions with local scientists and managers resulted in a proposal to overhaul the groundwater monitoring system. This system provides input for the basin-wide strategy.

Strategic Basin Planning for Ganga River Basin in India


In the city of Santiago de Cali in Colombia, Deltares and IHE are working with local water authorities and local professionals to implement the groundwater management plan for the aquifer beneath the city. The priorities are: to set up a sound water balance, and to analyse the impact of riverbank filtration and the contamination coming from an old landfill. To assess the water balance and understand how groundwater is replenished via the riverbed, we installed several piezometers (water pressure gauges) with groundwater level loggers. Surface water and groundwater samples are also being collected for chemical analysis. In this way, we are validating the existing computer model to calculate the water balance. At the landfill, we use boreholes and geophysical surveys to acquire more information about the subsurface. This information is used to validate a computer model for groundwater transport that was developed to assess the movement of the contaminant plume in the subsurface. The model will be used to assess the impact of a range of measures for mitigating groundwater contamination.

North Sea sand

The Netherlands uses sand to defend a large part of its coastline. The best known long-term replenishment project is the Sand Motor. That sand is taken from the North Sea. But the North Sea also has other functions: nature, fishing and energy (wind farms). With Rijkswaterstaat, we set up a minerals information system for the North Sea which shows, for example, where the sand is located that is suitable for replenishment work. In that way, it becomes clear where sand extraction collides with other functions. We base this work on geological borings and seismic data.

Sand from the North Sea