SEME-BIOSE : Beyond resilience

Project idea

SEME-BIOSE is a pilot project whose objective is to mitigate in the short term the effects of erosion on the Senegalese coast, one of the most affected countries in Africa. The experimental site is a 4 km coastal strip from Rufisque to Bargny marked by erosion and the strong presence of industries. We propose an alternative based on a « land-sea » approach. It is a question of being part of a protection framework that integrates coastal development through a set of strategies both on land (dunes,...) and in water (reefs,...) that combine to reduce wave action, prevent erosion, generally rebuild the coast and promote the development of sea-related activities.

The origin of the title comes from a deep desire to launch an appeal ! Not just a call to action, but also and above all a call to conscience. Indeed, it is not a question of « when to sow ? », but rather of » (what, how and why) sowing ? « because you sow every day and every moment, and the results are there sooner or later. Sowing is an act that involves strong responsibilities that are often overlooked. Sowing is investing for ourselves and for others. We therefore see the need to sow in the hearts of men values that will make them responsible and virtuous citizens. This title also evokes the symbiosis that we put forward in our project, between blue and green, between land and sea, but above all between man and nature.

Project description

Our beautiful planet is facing two major problems today. These are climate change and the population explosion. However, macro-economists tell us that Africa will be a major contributor to the exponential population growth to come and will host about a quarter of the world’s population in 2050. In addition, with 46% of its population living in extreme poverty, a fraction of 38 coastal states out of 54 countries, and the sea swallowing in some areas more than 10 metres per year, the situation is all the more intriguing. It is even more so for us, given the situation of the populations of these areas, who derive their income mainly from the sea. The case of youth has become such an emergency in recent years that crossing the Mediterranean by canoe becomes an option for many of these young people. Faced with this situation, we see the need for action.

In the short term, the project aims to increase the economic, social and ecological resilience of the Senegalese coastal populations. The different interventions are organized in five strata: The demolition of ruins and dangerous buildings located at a distance from the waterfront allows the beach to be freed and reduces the pressure on it. Eco-domains made of local materials make it possible to relocate displaced populations inland on hollow teeth. The use of windbreaks makes it possible to naturally restore the dune cordon on the back beach and create a resilient park. The creation of coral reefs and the restoration of mangroves promote biodiversity development, wave attenuation and optimize sediment deposition in deltas. The creation of artificial islands makes it possible to control swells and prevent sand from leaving the coastal system while developing economic and social activities. An extension offshore, through a floating architecture aims to optimize and democratize activities related to the blue economy while respecting the environment. In addition, the foundations of the footbridges leading to the islets are designed to stabilize the beach and deltas, optimize sediment deposition and create walking spaces with spectacular views of the landscape and extraordinary experiences, without disturbing the drifting shoreline, which is itself a balance. So, as the sea advances, we emerge. Life with the sea ceases to be a fight, and becomes a symbiosis.

Briefly, the project can be summarized as follows :
SEME to designate awareness, investment, action to anticipate the future and BIOSE for Biodiversity, Integrity, Order, Synthesis, Emergence are the qualifiers that best define the project; hence the title «SEME-BIOSE».

Technical information

A- Constructive methods

- For the islets, tetrapods and trapezes will be used. The technique used is innovative and the result of multiple studies and experiments conducted by geologists. It makes it possible to build durable and nature-friendly structures at much lower costs than anything already being done in terms of protective structures. Tetrapods (2.4 metres high ; 4.5 tonnes and 2 to 3 cubic metres of volume capable of withstanding pressures of eight storeys) are used to break up swells while trapezoids are used to accumulate sand. The tetrapod is a reinforced concrete block made of four truncated cones assembled by their bases, used more particularly in engineering with a curved profile and calculated in such a way that it minimizes the impact of marine flows. For their manufacture, techniques have been developed to exploit mining waste.
- The coral reef is replenished with low ph marine concrete blocks specially designed to provide fish habitat. Their geometry optimizes wave attenuation.
- The housing of the eco-domains as well as the rehabilitation will be made of local materials (...) while also exploiting the rubble from the destroyed buildings. Local construction techniques will also be promoted.
- The structure of the floating trusses will be made mainly of bamboos and wood, light and flexible materials offering multiple opportunities compared to other materials sometimes used. Moreover, they are ecological and warm materials. The hull will be made of an innovative material made from recycled plastics. This set will be based on a platform based on an ancestral principle, that of rafts. The floats used are recycled plastic drums (cylindrical in shape) assembled with wooden beams.


B- Biomimicry

- Artificial islets are the result of a mimicry of naturally resilient areas where the presence of natural islands helps to break swells while promoting the development of marine and terrestrial ecosystems.
- Biomimicry has also led us to explore innovative, simple and zero energy solutions to produce resources such as fresh water, a resource that is becoming increasingly scarce due to saline intrusion. We drew inspiration from the Namibian scarab (a small beetle living in the Namibian desert and having developed a rather ingenious strategy to produce its own fresh water) to supply the different parts of the project with fresh water, especially the farms, which will be able to be completely autonomous in fresh water without spending energy and without producing waste. Nets made of recycled plastic and old fishing nets are integrated into the buildings to produce fresh water from the humidity of the air while protecting the buildings from extreme heat. Small oases are created through small towers using the same principle to provide people with fresh water on a daily basis. Similarly, the use of a new recycled plastic-based material and ETFE film (Ethylene Tetra-Fluoro Ethylene) for the shell of floating farms collects moisture from plant perspiration through condensation. Fine droplets of fresh water form on the inner (rounded) wall of the structure’s shell and run off to the base where they are collected and stored in tanks for reuse.
As a result, farms become self-sufficient in fresh water without consuming energy.
- The symbiosis visible at all levels of our project has been inspired by natural processes and ecosystems.


C- Bioclimatism

- The architectural forms of the eco-domain housing and floating structures are mainly based on bioclimatic principles. They make it possible to make the most of nature while respecting it. The natural light and ventilation inputs are optimized for the development of humans and ecosystems created in the project through the farms. New types of materials make it possible to exploit the most accessible natural resources in the project environment in order to transform them into opportunities to compensate for the scarcity of certain resources such as fresh water.


D- Ecological principles

- Turning problems into opportunities through the recycling of plastic waste and drums, mining waste and landfill waste that is used as construction materials.
- Exploitation of accessible renewable energies (solar energy) through solar farms.
- Fresh water production without energy consumption
- Water pollution control and cleaning
- Reforestation and public awareness
- Creation of virtuous cycles (vegetable fish, ...)
- Association of vegetable gardens with each housing module ; this has a social and economic value.
- Reducing the impact of trampling on the beach by creating gentle traffic lanes.

Co-authors

Mesmer Ndienang Dapabko