Coastal erosion management in Accra: Combining local knowledge and empirical research

Abstract

Coastal erosion along the Accra coast has become a chronic phenomenon that threatens both life and property. The issue has assumed a centre stage of national debate in recent times because of its impact on the coastal communities. Lack of reliable geospatial data hinders effective scientific investigations into the changing trends in the shoreline position. However, knowledge about coastal erosion, by the local people, and how far the shoreline has migrated inland over time is high in the coastal communities in Accra. This opens a new chapter in coastal erosion research to include local knowledge of the local settlers in developing sustainable coastal management. This article adopted a scientific approach to estimate rate of erosion and tested the results against perceived erosion trend by the local settlers. The study used a 1974 digital topographic map and 1996 aerial photographs. The end point rate statistical method in DSAS was used to compute the rates of change. The short-term rate of change for the 22-year period under study was estimated as -0.91 m/annum ± 0.49 m/annum. It was revealed that about 79% of the shoreline is eroding, while the remaining 21% is either stabilised or accreting. It emerged, from semi-structured interviews with inhabitants in the Accra coastal communities, that an average of about 30 m of coastal lands are perceived to have been lost to erosion for a period of about 20 years. This translates to a historic rate of change of about 1.5 m/year, which corroborates the results of the scientific study. Again this study has established that the local knowledge of the inhabitants, about coastal erosion, can serve as reliable information under scarcity of scientific data for coastal erosion analyses in developing countries.

Climate Change Information for Regional Impact and for Risk Assessment

“…Mentaschi et al (2018) report a coastal area losses of 160 km 2 and 460 km 2 over a 30-year period along the Atlantic and Indian Ocean coasts of the continent. At the more regional level, in Ghana along the Gulf of Guinea about 79% of the shoreline was found to be retreating while 21% was found to be stable or prograding over the period 1974-1996(Addo and Addo, 2016.…”

Soaring Building Collapses in Southern Mediterranean Coasts: Hydroclimatic Drivers & Adaptive Landscape Mitigations

“…Recent observations employing digital topographic maps and aerial photogrammetry revealed that 79% of the shoreline is currently experiencing erosion, causing severe damage to coastal structures (Fig. 1e) (Addo & Addo, 2016). Reports of coastal building collapses in Africa are particularly difficult to assess due to the lack of accessible public records, unreported incidents, and local authorities often unable to identify the cause of these structural failures.…”

Contemporary Global Coastal Management Strategies and Coastal Infrastructure and Their Application in Ghana: A Systematic Literature Review

“…Many researchers [41,53,57,58] identify the key coastal management policy gaps in Ghana to include: (1) the absence of shoreline management plans (SMPs) to regulate which coastal management policy (HTL, ATL, MR, and NAI) to apply for a particular coast or region; (2) the multiplicity of coastal management regulations; (3) the multiplicity of disjointed coastal management institutions; (4) the non-implementation of coastal management decisions and environmental laws, a culture that has worsened problems of brisk real estate developments, encroachment into wetlands and land degradation [54], and coastal sediment mining [59], altogether contributing to severe coastal erosion and unsustainable coastal changes. Traditionally, exploitation of coastal sediment is considered an endowment that coastal communities have a right to [54,59]; (5) the exclusion of key stakeholders, including coastal communities and research institutions, from coastal management decision-making, from planning to implementation [53].…”