Água Grande District Coastal protection
Água Grande District Coastal protection
Location: Água Grande, São Tomé and PrincipProject type: Vulnerability analysis, Feasibility study and Environmental and Social Impact Assessment
Year: 2017-2018
Client: Ministry of Infrastructure, Natural Resources and Environment (MIRNA), funded by Rijksdienst voor Ondernemend Nederland (RVO)
Consortium partners: CDR International, REBEL group, IHE Delft, VE-R, Move Mobility, Shore Monitoring & Research
The coastal area of Água Grande district covers an area of 16.5 km2 that ranges from São Tomé airport to the community of Praia Melão. The district includes both the Bay of Ana Chaves and the Praia Lagarto Bay. The two bay areas suffer from the consequences of strong sea turbulence mainly caused by the rise of the sea level and increased storm events related to climate change. The main infrastructure located along the coast, including access roads, pavements for pedestrians, small boats of artisanal fishermen, protective walls, among others, have been suffering from accelerated and regular degradation.
In this project a solution driven approach, focused on a feasible coastal protection design, was combined with a multi-sectoral approach, by integrating different sectors including but not limited to tourism, fisheries and urban planning.
A vulnerability analysis to assess the hotspots for coastal erosion and damage to coastal infrastructure. Hydrodynamic modelling of storms was done to predict storm erosion for beaches and damage to the coastal structures and roads.
Based on the hotspots and wishes of stakeholders to upgrade the coastal road infrastructure, three alternatives were defined for coastal protection and road rehabilitation. The focus with the alternatives was multi-sectoral, including areas for tourism and areas for fishery. The designs for coastal protection built upon the existing structures in combination with soft solutions such as beach nourishments. For this purpose in Ana Chaves bay, fishery landing sites were incorporated in the design and a promenade was included along the strengthened seawall. In Lagarto bay, a beach nourishment in combination with revetment was proposed where steps were included in the revetment at several locations to allow for beach access.
