This is compounded by the underperformance of the few existing drains due to blockages from plastic waste and rubbish in gutters, a policy brief on flooding on some five Municipalities in the Greater Accra Metropolitan Area said.
It, therefore, suggested the integration of infrastructure and ecosystem-based solutions to effectively manage flood in the city.
The brief also recommended the need for the Authorities to prioritise nature-based solutions in developing and implementing climate change policymaking, as ecosystem-based adaptation often yielded higher net benefits than conventional options.
It said afforestation, for example, can provide greater overall benefits by improving livelihoods and providing other social and economic benefits when trees of economic value were planted.
The policy brief is the outcome of a panel discussion on flooding in Accra and how nature-based solutions can be used to resolve the problem.
It was organized by the country lead of Climate and Development Knowledge Network (CDKN) in collaboration with five municipalities, namely, Ga East, Ga Central, Adentan, Nkwantanang Medina and Kpone Katamanso Municipalities.
The report also identified other factors including urban sprawl, which is leading to unplanned and unserved communities; construction in wetland areas; and the increased use of impermeable hard surfaces; all of which limit natural drainage.
“Lastly, an increase in extreme weather events as a result of climate change has resulted in more intense rainfall,” it said, adding “there is, therefore, a clear need for the various municipal and district assemblies to better understand and effectively manage existing and future risks, and to liaise with other stakeholders to devise a roadmap on how to effectively manage flooding”.
The report noted that ecosystem-based adaptation (EbA) approach could be used in finding a solution to the recurring flooding problems in Accra.
EbA is a nature-based approach that uses biodiversity or ecosystem services to help people adapt to the adverse effects of climate change.
An example is the practice of restoring a wetland habitat within a catchment area. Wetlands contribute to flood attenuation by storing water and absorbing excess flow from rivers or other water bodies that overflow, it added.
That, it said, assist with erosion control, which could decrease the silting up of waterways, while recharging groundwater. Wetland plants are particularly good at controlling erosion by reducing stream energy and stabilising soil, allowing for better recovery of these systems after a damaging flood event.
The report said one such plant is vetiver grass, which helps to control erosion by forming a simple vegetative barrier (a hedge) made up of upright, rigid, dense and deeply-rooted clump grass that slows runoff, allowing sediments to stay on-site and eventually form terraces.
It noted that implementing effective drainage systems, including mapping natural drainage sites in municipalities and protecting them from development was crucial for solving flood issues in most municipal and district assemblies in Accra.
“Strictly enforcing building laws to avoid building on waterways and in wetlands, Municipal and District Assemblies coming together and collaborating to find solutions to flooding in their areas as well as facilitating the sharing of lessons among municipal and district assemblies is also necessary,” it added.
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