Project by: Inge Kersten & Jorrit Noordhuizen, Netherlands
Location: Nags Head, Kill Devil Hills &Kitty Hawk area, North Carolina, USA
Client: Wageningen University MSc thesis
Landscape as infrastructure for coastal protection
The designers of Vibrant Land show how the enhancement of landscape flows can foster responsive engagement between the natural forces and human inhabitants in a degraded coastal landscape and by doing so can stimulate resilience, flexibility and vibrancy.
The coast of North Carolina (USA) consists of natural barrier islands that protect the low and fragile mainland from the rolling waves of the North Atlantic ocean, and serve as a habitat and breeding ground for many wildlife species. Due to its attraction, rapid urbanization took place in the second half of the last century that ignored local knowledge and spread constructions all over the islands up to the dunes and beach, causing conflict with natural processes such as storm erosion, sand deposition and dune succession. The highly dynamic natural character of the islands—shaped by waves and wind—now frictions with the human-imposed static urban fabric, since this fabric leaves no room for natural regenerative processes. The designers therefore suggest a new approach: one that can handle uncertainty and system dynamics and can accommodate an array of both human and natural habitats.
The design focusses on the area of Nags Head, Kill Devil Hills and Kitty Hawk, since it provides a clear cross section of the challenges that face this area in the coming decades. Here, the island’s essential dune barrier has almost vanished, while at the backside of the island, the marsh is nearly gone due to erosion and building activities. The design proposal presents itself in timelapses of ten years and on the scale of a neighbourhood, showing how the landscape can be adjusted and improved with small steps by starting on a small scale.
How it works
According to the designers, a small-scale approach is essential for making people aware of their interaction with the landscape, so that they can relate to the measures that are proposed. Therefore, gradual change over time—starting with ‘quick-win’ opportunities—will give inhabitants sufficient time to get used to transformations within their environment, hereby making the changes more easily accepted.
First, the island landscape is divided into several landscape zones based on different character and processes; dunes, forest and marshlands. These zones are used to enrich the local landscape experience, as well as form the basis for several landscape interventions.
The designers then start by identifying ‘left-over’ space on empty plots, between buildings and along roads. These leftover ‘voids’ form a substantial part of the total surface of the urban fabric and form a perfect basis for the reorganization of the landscape. The usable void space is enlarged by changes in the parcelling grid and unpaving the surface. The standardized road network is optimized; unnecessary connections are removed or narrowed down, the monotonous grid is diversified and given hierarchy by bundling car infrastructure, while (semi-)public spaces are added. In some areas, almost half of the tarmac is eliminated, while maintaining the same level of accessibility. Voids can now be activated in three ways:
Since robust dunes create a safe backside where extensive and robust forests and marshes can develop naturally, a strong dune-landscape is fundamental for a robust and sustainable island. First, room is given to natural flows by creating a network of sand catchment and transportation within the voids, hereby integrating natural landscape dynamics with the urban fabric. Voids located within the first 150 meters from the shoreline are activated for sand catchment, since this is the area in which most overwash sand and most eolian-transported sand is deposited. By placing sand catchment structures (sand fences), dunes are able to grow dunes in a relatively short time span.
Second, voids are used for expanding the tree canopy of the maritime forest by planting Loblolly pines (Pinus Taeda). On the many empty plots and wide road profiles, the natural tree shelter will be enlarged giving room to ecological habitats and simultaneously mitigate the harsher oceanfront climate, making it a more pleasant environment for permanent residents in this area. Informal gathering spaces with a communal entrance are located between groups of houses: buildings become embedded in their local landscape zone and will relate less to the road network and more to their surroundings. This fabric of landscape variety and informal spaces will contribute to a more typical ambience of the area that fosters (social) interaction.
Third, voids are activated for creating a robust and resilient marsh edge. Shallow parts of the marshes give opportunity to let the island grow by combining this natural process with human elements. By adding low-cost wooden piers—with sufficient underwater structure—to the private piers present, sediment is caught which will eventually silt up and lead to marsh vegetation growth and expanding marshes. The piers make the landscape of the salt marsh much more accessible as well; providing excellent access for experiencing the actual growth and dynamics of this side of the landscape. Publications on using marsh growth for coastal defence show that marshes are able to grow along with coastal dynamics and sea level rise.
Essential in this design proposal is the element of time. Transformations will only occur by letting time do it’s job. Also, over time, poorly placed residential buildings will be relocated, shifting them out of the primary dunes and into the maritime forest.
Overall, the landscape will express its diversity as local site-specific differences become more visible, enriching the daily landscape experience. By small and simple interventions a large transformation can be triggered, resulting in a more robust and resilient landscape that is safer and more vibrant.