Erosion Based Urbanism

Sustainable habitat solutions for the Equatorial Pacific belt
Kiribati

Erosion Based Urbanism

Stopping coastal erosion

This project focuses on Kiribati, a country in the central Pacific Ocean, formed by 32 atolls and an elevated coral island. Considering that Kiribati’s territory is 99.9% ocean water, it is one of our main goals to help the country to preserve the small percentage of mainland available in their territory, and if possible, to increase it.

The current state of this project is represented by Kiribati Adaptation Program, a program initiated by the World Bank and funded by entities such as the Asian Development Bank, where sea walls are being proposed as the solution to stop sea-level rise effects on atolls.

However, these types of hard and static interventions create secondary issues due to the deviation of natural cycles such as ocean current and wind. Nature always finds its way, and because of these static walls/defenses, water is inundating areas which are not enclosed by these walls, thus contaminating groundwaters. It also increases erosion effects in other areas. An example occurred in Tarawa (the main island) when the expressway was built to connect Betio Island to the rest of the atoll, developed by New Zealand. The result of this intervention was the erosion of a small island located within the lagoon of the atoll, called Bikeman Island.

Given the failure presented by sea walls and other hard interventions, we propose the use of organic systems to protect Kiribati's mainland, ones that can adapt with the dynamism of atolls based on the growth and erosion of land. In this sense, the following techniques can be replicated and applied to similar ecosystems: a) Electrochemical reef construction, a way to regenerate coral reefs based on electro-estimulation; b) Regenerating autochthonous flora such as mangroves, or algae; c) Construction system to be used, based on local materials and construction methods. Our proposal develops these possibilities in detail.

The urban planning approach

Vernacular architecture in Kiribati has enabled atoll dwellers to integrate construction with the dynamicity of atolls for centuries, without disrupting its cycles, and in the most sustainable way. For this, it has chosen ephemerality over permanence, thus includes nomadic structures for adaptation. It differs from Western architecture in its mobility and adaptation to the environment, rather than submitting the environment to the urban need. Globalization is dominated by Western influence, and its arrival/implementation in Pacific Islands can only confront with the atolls landscape due to its stationary ideal, rather than work with it.

Kiribati's traditional housing unit is called Kia Kia, and uses few enclosures thanks to the tropical climate. Their roofs are high, as they help with ventilation; the buoyancy of hot air keeps heat in upper level, away from the living space. Units are slightly elevated above the ground with stilts, so moving nutrients and organisms can pass through both on mainland and on water mediums. It is an architecture that uses local materials, being palm trees the main construction medium with which they fabricate structures and thatched roofs.

Wood construction near the coast decays faster, something that Western architecture codes and regulations try to avoid and to prevent due to the intentional stationary vision of architecture and real estate. However the decay of architecture brings some concepts akin to the sustainability of dwelling on atoll nations, explained as follows: a) it enables the mobility of architecture, of importance for a dynamic ecosystem such as atolls; b) this mobility strengthens ties at the community, where neighbors help each other in the relocation and reconstruction of housing units; c) it contributes to the carbon cycle, as the palm tree traps carbon emissions, embedding in the molecular structure transformed carbon in the form of sugars within its leaves, trunk, and stems. With the decay of wood, this sequestered carbon falls in the bottom of the sea, doing a similar job as phytoplankton.

Based on these considerations, the project aims to present efficient and useful urban models specifically for its environment.

Credits

A project for LAIA Stem, USA
Authors: Gabriel Muñoz Moreno, Jordi Muro
Team: LAIA Lab NY
Location: Equatorial Pacific, Kiribati
Production: 2018-2019

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Paper Erosion Based Urbanism - Kiribati