Nature-Based Infrastructure for Flood Resilience in Ghana

In Sekondi-Takoradi, Ghana, climate change and rapid urbanization have increased the frequency and severity of flooding, causing widespread damage to homes, infrastructure, and ecosystems. Heavy rains frequently overwhelm the city’s drainage systems, cutting off communities and threatening lives and livelihoods, especially in vulnerable low-lying areas. 

In response, the Sekondi-Takoradi Metropolitan Assembly (STMA) has proposed a hybrid infrastructure plan that integrates engineered drainage improvements with nature-based interventions like wetland restoration, green corridors, and urban gardens.

In collaboration with the Covenant of Mayors in Sub-Saharan Africa, the NBI Global Resource Centre assessed the social, environmental, and economic outcomes of the proposed interventions. The assessment compares a business-as-usual scenario with a hybrid approach (nature-based and grey infrastructure). It focuses on two priority locations—Sekondi Market and Bakado—that are highly exposed to flood risks. 

The project valuation quantified the environmental, social, and economic impacts of the proposed hybrid interventions, using systems thinking, climate scenarios, and cost-benefit analysis. The valuation estimated the benefits of implementing the hybrid infrastructure compared to a no-action scenario, including: 

• Increased water retention and reduced flood damage 
• Increased carbon sequestration 
• Improved health outcomes and air quality 
• Increased land valuation 
• Reduced infrastructure maintenance due to flood damage 
• Local job creation and skills development 

Results indicate that for every USD 1 invested in hybrid infrastructure, the project returns between USD 3.26 and USD 13.53, depending on the flood valuation (low, high or average economic value). The avoided costs from flood damage are the primary driver of economic benefits, ranging from USD 163.29 million in the scenario with limited floods to USD 747.11 million in the scenario with severe flood damage. 

The results will support Sekondi-Takoradi Metropolitan Assembly and its partners in making informed investment decisions, aligning local policy with climate priorities, and potentially securing funding for future implementation.