The Omringdijk (ring dike) that encloses the island of Marken is a striking spatial element; it is low and in general amazingly narrow and steep: a highly compact shape. In addition, the dike has strikingly bent lines. This enables multiple views of both the island and the waters around it. The bent lines also create eye-catching ‘capes’ and ‘bays’
Both on its inside and outside, unique ‘pearls’ are located along the dike. On the inside the Rozewerf and the archaeological monument De Heuvel, on the outside the famed lighthouse (het Paard van Marken), the harbour and several ‘drowned villages’. The ring dike is the frame around the artwork that is Marken. This ‘frame’, however, does not conform to current water security norms. Primarily its height and inner stability are problematic. As a result, the dike needs reinforcement soon: over long stretches it needs to be broadened, and in many places also elevated.
This, however, is doubly problematic for Marken. On the one hand, because of lack of space: both insides and outsides of the dike border on terrains of great archaeological, cultural-historical and ecological value. On the other hand, because of the peat soils the dike rests on: these soils are highly prone to subsidence. It makes dike elevation only temporarily effective.
Dike improvements on Marken ask for customisation: for a solution that respects its special cultural-historical and spatial characteristics, and simultaneously, adequately prepares Marken for the future. Where possible, dike improvements must also add spatial, ecological and user value to the ring dike. Of course, this must not undermine security. The quest is to create a dike that guarantees water security within standard norms and simultaneously embodies a certain spatial quality. It is ‘safety first, quality too’.
To bring the dike back to norm standards, several solutions have been studied, leading to a number of alternatives. This includes the development of a ‘subsidence-free dike’ alternative. This alternative requires an enormous amount of ground work, in which the deeper, peaty soil is excavated down to the underlying sand layer. As such, it has extensive repercussions for the archaeological values on the outer edge of the dike. Moreover, it is a big question mark whether it would leave any room for the existing cultural-historical dike at all, and how old and new dike bodies would relate in such a scenario.
An important area of attention is the treatment of the bent lines of the current dike. Dike improvement inescapably leads to a broader dike. This directly affects its characteristically bent trajectory. Precisely the narrowness of the dike makes it ‘flexible’, allows it to easily and sharply change its course. Compare it to a rope: with a thick rope, contours are much harder to follow than with a thin wire. Principles like these were included in further technical and design development, that led to the final assessment of each alternative on aspects such as costs, manageability and spatial quality.
– Partner Steven Slabbers, BoschSlabbers
To that end, in 2015 the Framework Spatial Quality Dike Improvements Marken was approved. The framework describes the dike’s history, identifies its qualities and proposes ways to handle these qualities in the coming improvement project. As such, the framework provided a basis for several alternatives with potential, and eventually led to an alternative of preference.
In 2017, a ‘Memorandum of Spatial Design Criteria’ was drafted for the further spatial development of the dike body and its connection to its surroundings.
Title: Dike reinforcement Marken
Location: Isle of Marken, NL
Size: 8,7 km
Type: Dike reinforcement, framework for spatial quality, memorandum on design principles
Image credits: BoschSlabbers
Project code: bs-L 17-18