The design concepts

4.1 The design concepts

Mount concept (Terp)

The mount concept follows a traditional approach which aims at prevention of flooding under all circumstances. The ground level for the whole area is raised up to a safe level. Stadswerven is raised up to NAP +4m. This level is in agreement with the design water level predicted for 2100 according to the WB21 climate scenarios. No other measures, such as adjusted building concepts or infrastructure, are applied. This concept provides a safe environment up to the design water level. If the water levels exceed the design level, the area could become flooded.

The Mount concept is applicable in the downstream zone of a river. In other situations (in the upstream zone of a river) this concept will act as an obstruction causing water levels to rise during high river discharges. The Mount concept is therefore not applicable in the upstream zone of a river. An exception can be made for areas which are already high but need to be elevated to comply with changing water levels due to climate change.

For the Mount concept no flooding calculations were made. Due to the elevation of the area no flooding occurs under the conditions as evaluated within the flooding scenarios.

Integrated floodwall concept (Vloedfronten)

The Integrated floodwall concept, integrates flood defences into the buildings and public space forming a floodwall surrounding (part of) the urban area. Examples of such defences are houses with raised floor levels, elevations in the public space sometimes combined with other functions such as a car park. Inspiration for possible measures was found within the old city of Dordrecht.

Parts of the old city have been subjected to flooding for centuries. In the old centre specific building concepts and public design have been applied to cope with the frequent flooding.

For Stadswerven the defences form a wall which withstands a flood up to the design water level. A large part of the Stadswerven area is protected by the floodwall. The areas not enclosed by the floodwall, are designed to cope with flooding. Optionally within the area protected by the floodwall, additional measures can be taken, such as wet proof housing. This is done to anticipate on a failure of the floodwall.

The Integrated floodwall concept allows the flood water to touch the urban area. By integrating flood defences within the housing and public zone, flooding becomes part of life. The possibility of failure of the floodwall should be taken into consideration though.

Figure 4.1 gives a 3-D impression of the integrated floodwall concept for Stadswerven. The red area illustrated the location of the barrier and area’s already elevated to a level of NAP +4m in the present situation.

Figure 4.1 Integrated floodwall concept. The red area illustrated the location of the floodwall and areas elevated to a level of NAP +4m.

Watersteps concept (Watertreden)

The Watersteps concept incorporates building concepts which are able to cope with flooding. Instead of trying to keep the water out, the river becomes part of the design The Watersteps concept incorporates building concepts which are able to cope with flooding. Instead of trying to keep the water out, the river becomes part of the design

Figure 4.2 gives a 3-D impression of the Watersteps concept applied to Stadswerven. The red area illustrated area which is elevated to a safe level of NAP +4m. Around the Wantij areas are designated for floating houses, houses located in the water creating a Venice like setting and for different types of wet and dry proof building concepts.

Houses located in the water

Area suitable for a range of flood proof concepts

Wantij

Area suitable for floating houses

Figure 4.2 Watersteps concept. The red area illustrated the area which is elevated to a level of NAP +4m. Around the river Wantij, floating houses are planned. These are not illustrated in the figure.