7.2.3 Building with Nature in the Coastal Environment of Tema
‘The city of Tema is home to the largest port of Ghana. Situated near Accra on the Gulf of Guinea, Tema was developed specifically to support its port, which was opened in 1962. The presence of the port attracted industries dependent on the port, and the Port of Tema became a catalyst for urban development. Indeed, Tema was envisioned to become the industrial center of the country…. Tema’s port is the biggest of the country, serving both Accra and the Volta Delta. The port is currently undergoing a 1.5 billion dollar expansion, more than tripling its container handling capacity from 1 million to 3.5 million TEU ….’ (van den Houten, 2017).
Owing to coastal erosion and increased salt intrusion with concomitant loss of livelihood, people are continually migrating from the nearby Volta Delta. Many of these people settle in Tema, seeking a better future. The population of Tema is growing steadily, and this effect will strengthen with the expansion of the harbour.
A 2018 map of Tema is provided here. The following locations are indicated: Tema City, Tema Port, the new port development area, the crowded fishing harbour, Sakumono Village, the Sakumono Lagoon, and Church Village. Tema New Town, which is where the original inhabitants were relocated when the port was built in 1962, is located east of the Tema Fishing Harbour.
van den Houten, J. (2017). A system dynamics exploration of port-city development. the case of Tema, Ghana. MSc Thesis, Delft University of Technology, Delft, Netherlands.
- Restoring the connection of the Sakumono Lagoon with the sea.
This lagoon is a RAMSAR wetland – a wetland of international significance for migratory and resident birds. The coastal road connecting Tema to Accra was built across the mouth of the Sakumono Lagoon. Two large culverts now allow water to flow out of the lagoon, but the inflow of seawater is limited to a small volume under high wave conditions. This has meant that the fish stocks in the lagoon have declined and the type of fish living there has changed to species that are tolerant of brackish water. The vegetation has also changed and the mud flats are covered in coastal scrub, while thick reed beds extend to within a kilometer of the mouth and choke the upper channels. The constrained connection with the sea has caused the character and functioning of the lagoon to change. A degree of restoration could be achieved by increasing the size and number of culverts at the mouth, and decreasing the water level at which exchange becomes possible (deepening the culverts).
- Reducing the risk of flooding, near Church village
By dredging the channel of the Sakumono Lagoon, and removing some of the reeds in the channel itself, the high waters from the river can drain more quickly towards the mouth. The water can only drain effectively through the mouth if there are more and deeper culverts at the mouth.
- Fully rehabilitating the Sakumono Lagoon
This is by far the most beneficial option for the ecosystem, and for those dependent on its resources e.g. the fisherman of Sakumono Village. It would involve designing a bridge over the estuary mouth and fully opening the lagoon to the sea. As there are plans to widen and repair the coastal road within the next 5 to 10 years, this option of a bridge is feasible. Such an option would have to be carefully designed and there would need to be a mouth management monitoring programme. For small, wave dominated lagoons such as those occurring along the Ghanaian coast, seawater can serve to improve the water quality of the lagoon and to restore biodiversity.
- Building with Nature measures within the harbour or along the breakwaters
According to de Boer et al. (2019) below, potential measures include:
- Breakwaters functioning as artificial reefs;
- Biological concrete for quay walls;
- Artificial habitat creation within the port;
- Novel resurfacing materials;
- Hanging ropes from poles or pontoons to enhance attachment of marine organisms.
- Sand nourishment along the shoreline at Tema New Town
Tema New Town is on the leeward side of the harbour in terms of sand transport and the shoreline experiences ongoing erosion. Nourishment of the beaches with sand, would serve to address this ongoing problem and would restore the sandy beach and dune habitat.
- Concerted effort to deal with plastic pollution along the coast
Volumes of plastic are found along the shoreline of Ghana, carried downstream from where it is thrown by the rivers and accumulating on the beaches. This is considered a problem by fishermen, and other uses of the coast and beaches.
To orientate you to the city of Tema and the locations mentioned in the stakeholder interviews, a satellite image is provided immediately below.
This is followed by a list of potential Building with Nature interventions within Tema Port and the surrounding area. To help you in understanding why these interventions and not others were selected, a slide presentation by Prof Kwasi Appeaning Addo and ir. Wiebe de Boer follows. They explain the structural erosion that has been occurring along the Ghanaian coast near Tema. This means that sand is in short supply, eliminating as an option the large scale sandy options applied along the coast of Holland, like the Sand Engine.
The list of Building with Nature options is not meant to be exhaustive. It is designed to give you the idea that an ecosystem-based approach requires you to think beyond the scale of the port itself and consider its situation in the wider coastal system.
This thinking is demonstrated by the journal paper by de Boer et al. (2019) which follows. Here, a framework that structures environment considerations in decision making on port development through all phases of port development is presented and applied to the Tema port expansion case.
Enjoy learning about more environmentally friendly options for the wider coastal area of Tema.
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