Blog Resilient Urban Water

by Dennis Kuijk

June 9, 2020

In my previous blog I wrote about a technically feasible project in which getting the residents involved once again created added value. The residents were actually all on the same wavelength, and that helped make the project very successful. But what happens if one person’s solution is another person’s problem? If for example you want to retain water to meet your needs in dry periods, but the retained water causes moisture problems? You will need to find a course between sufficient drought containment and the lowest possible, acceptable moisture levels. And preferably not reach a compromise that everyone has a problem with, but one that is actually effective. What we now realise is that our own climate resilience is not that great. Our choices are subject to the whims of the seasons. In the summer the drought is palpable and we want to infiltrate and retain more water. A drought period apparently helps bolster water awareness. When the days again grow longer and rainy weather raises groundwater levels, we immediately react by calling for the discharge of as much water as possible. 

Urban areas in low-lying delta regions actually confront numerous different challenges caused by the changing climate. The problems of water on the street or of heat islands are generally acknowledged. But this next example illustrates the conflicting interests I described above. For instance, I see high groundwater levels and poor soil permeability leading to the growth of moulds in buildings. But, of course, drought is again the ‘silent killer’ for both agricultural, and particularly urban areas. Urban green spaces dry up, wooden pile foundations deteriorate, land subsidence accelerates, just to mention a few examples – all problems incidentally that are in fact technically quite easy to solve on their own. But the quest for a joint solution is still not that easy if two problems arise simultaneously. Active groundwater level management is a good way of managing these kinds of problems in conjunction. The key to success lies in that little word: ‘active’. It means that you can adjust the dial to minimise the negative impact of groundwater level fluctuations for all those affected.  

Active Groundwater Level Management 

In the old city centre of Delft many of the houses have steel foundations, that is, they are built on a steel base on the ground, without foundation piles. This causes problems when the ground settles or sinks because of peat oxidation (land subsidence).  Land subsidence leads to a diminishing drainage depth under buildings and roadways. In such cases, if you lower groundwater levels further this will lead to further subsidence, and so on. In many cases a sound system design using the Active Groundwater Level Manager (in its Dutch acronym, AGAPE) is enough to prevent both groundwater flooding and low groundwater levels. Even if every groundwater level has its harmful implications, in many instances an acceptable middle course can be found. This sometimes implies that a stakeholder has to accept some damage or inconvenience, or needs to invest in some construction work. Actually, I would dare say that an approach using the AGAPE, on the basis of a transparent and thorough appraisal of the long- and short-term consequences for all the stakeholders, can produce solutions acceptable to everyone. This requires a high commitment by citizens and public authorities in a preliminary phase. And it requires that we, as engineers, do our very best in presenting and explaining all the potential factors of influence as simply and as clearly as possible. By taking an integrated approach, combined with knowledge at different scale levels, we can effectively resolve problems. Municipalities can make a big difference in this context. Providing insight into the urban groundwater, outlining the groundwater requirements and conditions, and proposing possible solutions to property owners. To my mind, the municipalities have an important task when it comes to keeping deltas liveable and habitable!   

by Dennis Kuijk

July 29, 2019

Dennis Kuijk is a civil engineer graduated from Delft University of Technology and is responsible for the development of the field of Resilient Urban Water at Dareius. Monthly he invites us to accompany him in his advisory work to share his experiences with visitors to the Dareius website.

In my work and sometimes personal life I receive questions about climate change and the vulnerability of our cities and living environments. In my role as advisor I see the various developments in climate change mitigation and adaptation such as new policies, regulations, technology and business models. I’ve also noticed an increasingly essential collaboration with other professions, processes and communication between stakeholder groups. Since we are all in the same proverbial boat, it’s only natural that the solutions we develop come from society at large as well.

In the past, requests that came in dealt with the design of rain or groundwater systems of an area – our work field was mostly limited to the subsurface layer. The surface layer, the part actually visible to inhabitants, was in most cases already designed. The amount of green space was pre-determined, the total amount of parking spaces was specified, and so on. It’s a rather important consideration, because it’s not possible to properly incorporate water amongst other natural flows safely into our environment if the various systems above and below the surface are viewed separately.

In recent years there seems to be a collectively improved understanding or re-discovery of these issues and the connections between professions. For example, in a current project I am designing the renovation of a neighbourhood in the village Pijnacker in cooperation with landscape architects, urban planners, administrators, and inhabitants. By doing this together, we not only create a robust solution for the neighbourhood but also learn from each others’ expertise and experience during the design process.

What brought us together?

The motivation for this partnership was both technical and practical: in this case it was about the area’s sensitivity to land subsidence. Certain street levels had subsided approximately 80cm in relation to the original ground floor of the residences; something inhabitants naturally suffer from. To be able to deal with the elevation differences (aboveground) and limit the subsidence in the future (belowground), specialists need to work together. Besides, it provides the perfect opportunity to combine engineering with local (inhabitants’) knowledge and experiences. In the village of Pijnacker we are using innovative systems to make the neighborhood climate proof, known as the Urban Waterbuffer. Using this system, the storage capacity for rainwater within the village greatly improves. This stored water is also used to maintain pre-determined, safe groundwater levels (in dry periods), which in turn limits potential subsidence or settlement. This may sound easy, but in practice the water needs to be collected, purified and infiltrated into a deeper aquifer. This incorporates different disciplines, like civil engineering, hydrogeology and spatial planning/design. This project marks the first time the Urban Waterbuffer is applied in conjunction with active groundwater level management.

Inhabitants are part of the eco-solution

In order to have an holistic and inclusive solution we first spoke to the local inhabitants and collected their concerns and wishes. We were encouraged to see how their climate awareness had grown and how they deal with the problems of their subsiding environment in a pragmatic way. The next step incorporates these requests with the technical requirements into the overall design – without the residents’ input, such a system will not function optimally. With this holistic approach, we not only build a resilient neighbourhood, but we also create a realistic and sustainable solution.

Want to know more?

For more information about Resilient Urban Water, please contact us at:

Dennis Kuijk MSc +31 6 82 92 14 88
Want to know more?