BISCAYNE BAY: TURN THE TIDE!
Comprehensive research and design project resulting in an integrated landscape approach for coastal restoration in Biscayne Bay through spatial and ecological interventions.
Project type · Graduation project and joint publication
Date · 2019
Location · Biscayne Bay, Florida USA
Mentors · Dr.ing. Steffen Nijhuis & Yuka Yoshida
Keywords · Ecological Restoration, Coastal Management, Mangrove Reforestation, Landscape Architecture, Spatial Design, Flood Protection, Urban Ecology, Design Research, Research by Design
In collaboration with:
Turn the tide: “To completely change the direction of something”
The coast of South Florida has undergone a drastic change in the last century and this has had a major impact on flood safety. Natural coastlines supporting mangrove and wetland have been transformed into urban water fronts consisting of seawalls and buildings. It is estimated that in the last 100 years, 40 percent of the mangrove coast has disappeared. This is very unfortunate, because this forest functions as a natural barrier between sea and land and provides the coastline with a natural levee which protects against flooding. This natural system has potential to adapt to the consequences of climate change that highly urbanized areas like Miami’s Biscayne Bay are already facing and which will increase rapidly in the future. Therefore, the restoration of mangrove forests stand out to be a future-oriented strategy of natural coastal protection for this area: a way to turn the tide!
This research identifies and explores design strategies and principles for the mangrove landscape of Biscayne Bay in order to reduce the flood risk of Miami Metropolitan Area, as well as provides aesthetic, ecological and functional qualities that contributes to the identity and resilience of this coastal region. This is done through design-related-research, that divides this research in two domains. Design research, which consist of a system analysis and examination of best practices and research by design, which involves design experiments.
The result is a layered landscape strategy that contributes to the harmony of the natural coastal landscape of Biscayne Bay and thereby restores its functions. The systematic strategy is converted into a spatial design, applying principles gathered from best practices. This landscape architectural design adds an extra dimension to the mangrove landscape that will invite the residents of the Miami Metropolitan Area to experience through exposure to changes and value its aesthetic and ecological qualities and protective functions.
The desired coastline for Biscayne Bay is a continuous mangrove landscape, consisting of three layers along the bay: wetland, mangrove forest and sea grass meadow. In the current situation, the mangrove landscape is depleted because the layers are fragmented and interrupted by the spatial limitations of the built environment and the canalized water system. The feasible situation is a fragmented but continuous mangrove landscape, which contains at least one of the layers. Existing parts in this layered structure, like fragments of mangroves or wetland, offer the opportunity to restore the desired landscape. The strategy is to preserve, restore and reintroduce the layers in a design for a continuous mangrove landscape with dynamic borders to enable expansion. If spatial limitations obstruct these actions, parts of the layer be shifted to an adjacent one and be interwoven with its context.
In the most northern part of the bay, the mangrove landscape barely exist anymore. Apart from a few small mangrove fragments and depleted meadow, there is no place for the landscape in this urbanized area. Shifting parts of the mangrove layer offshore is the concept for this urban zone of the bay. An island chain off the coast offers space for the mangrove new development. This barrier structure can substantially lower the water level and the impact of waves of storm surges. The mangroves improve and hold sedimentation, but also add spatial quality and aesthetic value to the area. The shape of the islands is based on a sedimentation experiment and the pattern is defined by the bay’s current and the topography and topology of the sea floor. The islands are situated in existing fairways or on the mudflat, to spare the sea grass meadow that supplies the islands with sediments so they can expand. The area between the shore is sheltered by the barriers islands and supports larger water based recreation.
The method used for researching and developing the strategy, considers landscape as a system consisting of three components: structure, process and actors. These three components are used as basic elements for the landscape architectural design. The island base is made of basalt rock material. Bigger islands are accessible and have a wider base that allows elements of the program, such as the routing, picnic places and observation points. The islands offer a new experience for the residents and local tourists in the northern part of the bay. The shape of the islands and their vegetation is constantly changing due to sedimentation and erosion. This form of diachronic change allows the user to experience the most important processes of the mangrove landscape. Paths and the circular bridge are a reference point to observe the development of the islands over time. Experiencing retreat and expansion of the vegetation, but also deviating high water levels, will make the user aware of the function of the mangrove landscape and value its role as a coastal defense system.
The scheme above illustrates the development of an barrier island that is also accessible. In the first phase, the base is constructed in the water and directly enables sedimentation and peat formation between the mangroves root system, which will cause growth of the islands in the following years. During this process, red mangroves move seaward and the black mangrove strip increases on the higher shores. After a decade, the slopes will be more elongated and can expand towards each other and form one bigger islands. However, the expansion is not based on stable rock or solid ground and could be washed away during a heavy storm. The base of the island will continue to exist and the process of expansion can start over again. Eventually, multiple islands can form clusters that would be strong enough to survive a storm and create a continuous barrier of mangrove landscape.