Higher Lanes and Public Planes

Myrna Ayoub: Details 1

by Myrna Ayoub (MArch II '16)

As sea-levels rise and the threat of flooding looms within South Beach Miami, new regulations and codes are responding through recommendations to elevate the city. The proposed flood level floor and raised roadway are an adaptation of elevation–a deliberate re-articulation of the ground-plane that creates a new urban threshold. By reworking these modifications, water can be absorbed, moved, or retained as opposed to shed, concealed, or pumped. The fluctuation of urban boundaries, manifest in the section in particular, reveals an exploration of levels that augment civic context. This project explores the potential manifestations for these new elevations through the study of three sites identified along the transect of 4th and 5th avenue. The typologies negotiate the parameters and accommodate the existing urban conditions to allow for the preservation of a dynamic/heterogeneous city and the resilience in the face of rising sea levels through the exploration of the urban section.

Hydrologies: This project explores section operations to maximize municipal stormwater management capacities. In the public realm, streets elevate with limestone-like fill to increase storage. New pervious ground cover materials slow runoff from overburdening existing drainage systems. In the private realm, new ground floors sit atop limestone filled “sponge pads” and elevated buildings cede ground to maximize sheet flow. In both realms, additional vegetation and their deep urban soils add stormwater infrastructure.

Spaces: The interior of the site is set aside for ecological performance. Low-maintenance native ecosystems are fostered to regenerate potential habitats and reduce open-space maintenance fees. Concentration of tree planting at the northern and southern tips suggest public parks and possible habitats that could spur from the alluvial channel. Topographical modifications foster the succession of native species. East-West corridors enable street tree planting schemes that organize and orient the block structure.

Infrastructure: This scenario views ongoing engineered infrastructures as a multi-layered system that provides pubic benefits and a new urban landscape. In addition to elevating the street roughly 5’ above current grade, mass transit is also introduced along 5th Street where it connects directly to the MacArthur Causeway. Pedestrian walkways and bikeways take precedence over vehicular traffic which is reduced in capacity and speed. Certain parts of the new ground plane are reimagined as extensions of public space.

Policies: Coordination between the public and private realms is paramount to creating seamless urban thresholds and transitions. A finer-grained zoning overlay map would be necessary to integrate suggested common flood elevations and regulate private properties to match such elevations. Where roads cross multiple jurisdictions, additional cooperation is necessary to ensure the successful design, construction, and maintenance of proposed section scenarios. FAR incentives on key corner properties would help initiate and accelerate their adaptive redevelopment.