One of our primary functions here, besides touring the landschap of the Netherlands is to work through a few quick design projects, or charettes. Generally, a design charette involves being given a particular problem and then coming together in small groups to quickly generate ideas. The point isn’t to fully flesh-out all the details of the solution but to react quickly with a few peers to see what the brainstorming session might stir up. Last week, the Cities on Water class participated in such a charette.
I wrote recently about my trip across the Houtribdijk in Flevoland east of Amsterdam. This dike was initially constructed in 1976 with the intention of draining part of the Zuiderzee for an agricultural polder called the Markerwaard but due to shifting financial considerations and societal pressures about ecological impacts, that empoldering has been indefinitely postponed. The lake that now exists where that polder would be is the 70,000 hectare Markermeer, one of the largest freshwater lakes in Europe.
Unfortunately, this lake is evolving into an ecological wasteland. The Markermeer has become a turbid, cloudy, nearly lifeless body of water because its clay bottom is constantly being churned by waves with nowhere for the accompanying silt to drain. This silt is described as a thick layer of yogurt that strangles the aquatic vegetation and stifles fish and microorganisms.
Recently, the Dutch Nature Preservation Society Natuurmonumenten was awarded 15million Euros to realize the Marker Wadden project in the north part of the Markermeer. The project involves digging trenches to trap the silt, constructing a large break water to calm the waves, and the subsequent fabrication of a dredge island from the silt dredged from the trenches.
Our charette problem asked us to help tease out some designs that might help make such an undertaking a reality. Working in groups of three, we spent three nights in nearby Lelystad where we would have constant contact with the Markermeer and its surrounding context. Each day we conducted bike tours of the shore to try to understand the enormous scale of this lake and met with a local ecologist who described the current and predicted conditions of the lake. We also were joined by our favorite local landscape architect Jan Wouter Bruggenkamp and the director of Natuurmonumenten Roel Posthoorn.
Our design for Marker Wadden, On the Horizon, is one that promotes the water of the Markermeer while utilizing techniques to generate new ecologies and spaces for people and wildlife. Recognizing the importance of the infinite sea that is the Markermeer, we accentuate the space by situating the islands just at the edge of sight from Lelystad. Acknowledging the cultural history of the Netherlands was a guiding factor of our analysis and design. By drawing from the form geometry of the agricultural lands of Holland, we proposed to initially construct our islands in a rectangle of precisely organized grid points. Just as the Markerwaard was to be a polder of farms but is now becoming a place given to the promotion of wilderness, the islands we have designed will, over time, transition to more organically shaped spaces. Our flexible design is one that anticipates change and evolves over time.
The technology used in the formation of our islands draws on the techniques traditionally used in Dutch poldering but also brings new ways of land formation to Holland. The initial sequence will include the construction of a riff to slow down the wave activity near the construction site and a trench will be dug near the riff for the settling of silts. Our riff includes the generation of energy from the waves by including oscillating wave cylinders in the infrastructure. Following the construction of the riff, the fabrication of the islands will begin. By installing a 5 meter grid of vertical poles embedded in the substrate 2 meters and emerging from the surface of the water 1 meter, we will begin the island formation. According to the US Army Corps of Engineers, 2-20 ha is the optimal size range of dredge islands for stability and avian habitat. A silt fence will be drawn around the basic island shapes anchored to the poles. Mechanical pumping will be used to deliver the silt into the cavity. As the cavities are filled, willow mats will be added to provide some stabilization for the silt. Over time, the islands will grow in height until they emerge on the surface of the Markermeer.
These islands will continuously transform due to fluctuating water levels and tidal activity. Plants of the various Dutch ecotones will be seeded or staked to provide a range of habitats for birds. The islands will eventually represent a gradation from mud flat to woodland. As these plants take hold, they will continue to stabilize the silt and become attractive, varied landscapes. Eventually, these islands will be robust enough to support occasional human visits for bird watching, hiking, and canoeing.
One of the strengths of our design is the flexibility to experiment with land formation. As the silt has been described as having the consistency of yogurt, construction will be a challenge. Because we are actually constructing many smaller islands rather than one large one, our design provides room to adapt to unexpected difficulties that might arise. Another strength is our engagement with the water in our design. The overall dimensions of the island will be 1000 hectares but rather than being a single body, the island will be comprised of spaces for water as well as land. Among the islands, the waters of the Markermeer will be like small rivers and tidal pools. Also, because of the configuration of our riff to the islands, there is a large body of water between. This water too would have another character apart from that of the larger Markermeer. While the lake water exhibits strong waves, the space between the riff and the islands would be calm enough for small boats.
The Markermeer is, as we learned, at its presently degraded state because it is cut off from the larger system of exchange that is necessary for a healthy ecosystem. Much like the adjacent Oostvaardersplassen, cutting a piece of nature out of its larger context results in a dysfunctional and dismal place. The charette gradually took on a growing complexity. For the first time since coming here, we were designing and redesigning our ideas. The more we learned, the more difficult it became to solve the problem. The more our plan evolved, the more we were forced to return to the original renderings.
Eventually, almost in a couple of hours, my group had a much better understanding of the complexities of our surroundings. Our design grew from an abstraction to some sort of a solution. We had sketches, renderings, and designs. We had a good understanding of what we were proposing.
As a design project, the challenges were fantastic. I enjoyed the process of moving through the design, of seeing something evolve from a few circles on a piece of paper to an articulated design with precise phases and realistic spaces. Forcing us to move quickly through the process released an energy that came through in the designs and in the presentations. Unlike many design projects where we have had several weeks to manufacture a space, The Marker Wadden charette challenged us to be efficient and knowledgeable. As a design team, we learned to believe in our design.