by Thijs Visser
March 11, 2020
Water plays an important role in spatial development. That’s why I’m often asked how one should deal with the water component in a spatial development plan. The reason for the question is clear. A development cannot have any negative consequences for the environment. And that’s why the water management in the plan must be in good order. To make sure this is the case, the public authorities have set down requirements for a plan’s water component. And it is on the basis of these requirements that I design a plan’s water management.
If the numbers are good
I see that the requirements are often defined in technical terms. This makes a plan implementable and testable. Every policy includes the plan’s minimum drainage, the volume of water to be stored and the maximum discharge. And these form the bases for the plan’s assessment. I often notice that a plan is almost automatically approved if these specific numbers are good. A blue mark on the layout drawing suffices for water storage. Hard numbers: hard water.
An extra dimension
Testing for bare, technical requirements is simple, but it has its limitations. For instance, the technical requirement concerning the water storage volume suggests that this must be effective. This means that the volume is sufficient to contribute to good water management within the plan, and to prevent any effects on the environment. But the objectives are four-dimensional, because they have to do with effects in space and time. There is no suitable approach to this, so there’s a risk that a solution will fail in achieving its objective.
And this at a time when effectiveness is a high priority. I see this emphasis on the importance of effective operation primarily in the way in which climate adaptation is positioned in policy. Besides the above-mentioned technical requirements, I now also have to demonstrate for instance that no flooding will occur in the case of extreme precipitation. This case perfectly illustrates the four dimensions: a combination of hard-to-estimate water volumes at unpredictable moments. It may be clear that a storage calculation alone is no longer enough, and that it needs to be supplemented with a thorough spatial analysis. To meet this need, Dareius has developed the Urban Water Design OpTioneering tool (UWDOT).
Simplicity in complexity
In UWDOT we model the planning area and its environment in the future situation. The planning area is built up virtually on the basis of publicly available data. The spatial development is uploaded, including a new water-level plan, on the basis of the design. This gives us an understanding of the actual effects of the plan on the environment and within the plan’s boundaries. Using a ground-level model, we can see where and how the precipitation surface runoff occurs. This makes it possible to test the effectiveness of water provisions under heavy precipitation.
UWDOT’s power lies in its capacity to clearly show the effects in less than a minute. This makes the tool perfectly suited for interactive design sessions. The model’s visualizations allow stakeholders to quickly absorb the results, which makes complex questions clear and interactively accessible.
I have so far applied UWDOT in more than ten projects. What strikes me is that the tool’s use contributes to the mutual understanding between, for instance, the public authorities and stakeholders, and that the effectiveness of the water provisions is placed center stage. Local problem areas and possible solution paths are quickly made apparent, allowing for the creation of spatial quality. Soft water, I would say.
The challenge we now face is to provide a legitimate place for the deeper substantive insights produced by UWDOT within a process that is structured on the basis of the bare, technical policy.
