Weighing the importance of water in spatial planning: basic principles
Are you the initiator of a spatial plan? Then you will have to write a water paragraph in which the weighting of water interests is central. We assess this 'weighting of water interests' on a number of topics:
Water and soil management
When choosing a location for a new spatial development or change of function, the water and soil system is the guiding factor. A high/dry location is preferable to a wet, low location. Building on solid soil is better than building on soft soil. Advice maps from the water board and the province provide insight into this.
Hydrologically Neutral Development (HND)
We adhere to the principle of hydrologically neutral development. This means that the new water situation must remain at least equal to the initial situation. The compensation rules 'damping = digging', 'paving = compensating' and 'reducing ground level storage = compensating' are leading in this regard.
Prevention of pollution
The Water Framework Directive stipulates that new developments must not cause any deterioration in water quality and/or ecology. Preventing pollution is therefore a prerequisite for weighing up water interests. We would be happy to work with you to find ways of improving water quality.
Separating dirty water and rainwater
Wastewater belongs in the sewer system. Clean rainwater should preferably be drained into the ground (infiltration) or into a watercourse. In existing built-up areas, we accept a compromise when only a combined sewer system is available: the separate supply of water flows to the existing combined sewer system. We do not agree with the construction of new combined sewer systems.
Reuse > infiltration > buffering > drainage
When draining clean rainwater, follow these steps: reuse > infiltration > buffering > drainage. Reusing rainwater is particularly interesting for large-scale facilities such as schools and office buildings. The collected rainwater can be used for flushing toilets, watering gardens, or washing machines.
If reuse is not possible, infiltration into the soil is preferable. This can be achieved naturally in sandy soil with a sufficiently low groundwater level, using gravel or an infiltration system. If this is not an option, rainwater can be buffered in a water storage facility to prevent flooding during heavy rainfall (delayed drainage). A final option is to create additional open water and discharge rainwater into a watercourse.
Water board interests
Various water board interests may come into play in spatial developments. These include the presence of:
- flood defenses and associated zoning;
- watercourses and hydraulic engineering works;
- (Pressure) pipes for the wastewater chain managed by the water board;
- milled and millable windmills;
- roads (still within a few municipalities);
- property of the water board.
For a proper assessment, it is important that you gain insight into the water interests that play a role in and around your planning area. You can easily gain insight into this at www.hetwateradvies.nl (formerly 'the Digital Water Test').
Multiple use of space
Usage functions can be combined. For example: a wadi can also be designed and managed above ground as a playground for children.
Water as an opportunity
Water is sometimes seen as a problem. However, water can also add value to spatial development. You can make use of the experiential value of water. After all, many people appreciate a beautiful water feature with accompanying greenery.