Soft solutions to combat coastal erosion in Senegal

Moussa Sall is coordinator of the Regional Unit of the West African Coastal Observation Mission (WACOM) at the Dakar Ecological Monitoring Centre in Senegal.

Céline Damery is Europe and International policy officer at France’s Coastal Protection Agency.

What causes coastal erosion?

Moussa Sall: Coastal erosion has been a recurring problem in West Africa for the past twenty years, bringing with it a slew of devastating consequences. The coast is a very fragile geographical area: more than 95% is made up of mangrove swamps and sands, so loose rocks, which have little resistance to sea swell.

The phenomenon of erosion is characterised by disruption in the balance between a coastline’s sea and land elements, resulting in a deficit of sediment in that land element. This erosion is certainly made much worse by climate change and the concatenation of extreme weather events (storms and cyclones). But it’s the compounding of several factors that causes the real problem. When natural phenomena combine with human and economic issues, the risk is magnified. The concentration of populations along the coast, the spread of industrial and tourist infrastructure, the expansion of ports and towns plus the proliferation of dams which restrict the flow of sediment toward the coast, all contribute to aggravating erosion. Careful land-use planning is therefore vital.  

What are the impacts of coastal erosion?

Moussa Sall: The impacts related to coastal erosion are largely social and economic. On the social front, affected populations typically find themselves at risk - for example, they’re in danger of losing their homes. Public authorities face significant difficulties in managing these impacts, particularly in densely-populated areas. On the economic front, activities such as fishing are affected. And in Senegal, fishing is the biggest export earner, supporting some 630,000 jobs. The tourism sector, centred mainly around the beachfront, is also badly affected, with hotels along the coast having lost most of their beaches.

Erosion is also synonymous with loss of biodiversity, especially in mangrove areas which are particularly rich in biodiversity and fishery resources. Along our West African coast some coconut forests have disappeared completely, together with the species they hosted.

How are you addressing these challenges on the ground?

Moussa Sall: We have to strengthen the resilience of populations, which means equipping local communities so they can resist climate change. That could involve building protective structures (the hard or “grey infrastructure”), or introducing so-called “soft” solutions in harmony with nature. The project we’re working on with the FFEM in Senegal, Togo and Benin focuses on soft solutions. We’ve identified pilot sites in these three countries that are particularly at risk of submersion and coastal erosion, where the proposed solutions vary from site to site.

For example, at Langue de Barbarie in the Saint-Louis Marine Protected Area, supported by the Coastal Conservation Agency and the charity SAVe, we’ve adopted fencing made from typha, (a fast-growing reed) to help retain the sand and allow the MPA to reforest the areas eroded, since they are heavily impacted by the ocean.

Céline Damery: The FFEM asked us to partner on the project and help the Saint-Louis MPA by sharing the expertise and knowledge we’ve gained about soft solutions. In France, the Coastal Conservation Agency owns a number of natural areas where we have been implementing soft adaptation measures for coastal protection over the last few years. In the Saint-Louis MPA we’ve been experimenting with fencing made from local typha reed, inspired by the chestnut palings used in France (“ganivelles”) to provide a barrier that captures wind-blown sand to re-build the dunes. It's been a year now and the initial results are positive. Thanks to the incredible responsiveness of the Saint-Louis MPA, which handled the installation, the dunes are gradually starting to re-build. Today one kilometre of coastline has nature-based solutions installed.

Moussa Sall: Yes, this technique is producing great results. Significant amounts of sand have been caught, stopping the flow of seawater towards the river side. As well as dune reconstruction and reforestation, we’re looking to introduce other soft solutions, such as the development of a local climate change adaptation plan in the Pilote Bar area, located a few kilometres to the south of Saint-Louis. The plan will draw on the results of technical studies which will identify areas at risk within the next 30 to 50 years, based on swell behaviour and climate factor changes. Based on that we'll be educating the population about what’s at stake and involving them, so that these areas will be reserved for uses other than housing or economic activity – recreation, for instance – in anticipation of future risks. We’ve already shared our approach in meetings with the respective communities and local authority. They’ve been highly receptive.

Céline Damery: Measures to combat erosion at local level must be holistic. Certainly, along with SAVe we contribute technical expertise: we provide advice on fabrication (permeability, tying-in with plant and non-plastic materials, etc.), orientation and sizing. Over and above these technical aspects, however, we also offer advice on nature-based site management to help with the area’s replanting. We draft protocols for monitoring biodiversity or landscapes, and help the MPA to welcome visitors. We also assist in overseeing agricultural practices to ensure they don't encroach on the protected area, that manure is used instead of fertilizers and that waste is dealt with on-site. It’s this holistic approach that allows local communities to be really hands-on with what happens in their area.

How do you share and disseminate lessons learned and successful solutions?

Céline Damery: The idea is to support the team in charge of the MPA so they can get to know the monitoring systems and eventually run them on their own once the project ends. So the missions we organise include this training component, allowing the on-site team to learn the approach and become familiar with the tools. Teams from six MPAs in Senegal will soon be trained in soft solutions and their monitoring. They’ll learn from the experiences of the Saint-Louis MPA and particularly from what the project has taught us.

Moussa Sall: The potential to scale-up this project is quite significant. What's being tried out in the three countries, whether it’s soft solutions tested at pilot sites or doctoral theses on coastal risks, can be replicated and used in other countries in the West African Economic and Monetary Union (WAEMU), particularly within the scope of the West African Coastal Observation Mission (WACOM), established in 2011.

We’ll also be relying on two regional institutions to help us replicate successful solutions. These are the Network of Marine Protected Areas in West Africa (RAMPAO) and the Regional Partnership for the Conservation of Coastal and Marine Areas in West Africa (PRCM). The RAMPAO has already identified a site in Benin at the mouth of the Mono River that can be set up as an MPA. It will play host to nature-based solutions thanks to the involvement of CoRDE, an NGO and key partner of the project at the local level. The PRCM has also partnered with us to disseminate the results at its global forums, which it holds on a regular basis.

In addition, countries involved in the WACA ResIP project, which is funded by the World Bank and is closely linked to the FFEM project, could take advantage of this experience and capitalise on the early results of typha fencing, for example.

Céline Damery: The use of local, low-cost materials allows for reproducibility. We’ve taken the concept of chestnut palings and successfully adapted it for use with local vegetation. If you look at other, older projects carried out by the Coastal Conservation Agency, you can see how chestnut palings evolved into “palmivelles” in Tunisia, made from palm trees, while in Senegal, they became typha fencing. The concept could of course be deployed elsewhere in West Africa using different local vegetation.