Building resilience to climate change through water retention solutions in Ca Mau City, Vietnam

Coastal cities in Vietnam are increasingly impacted by rapid environmental changes and the growing frequency and magnitude of hydrometeorological hazards, such as extreme precipitation and droughts. One of the most significant challenges posed by climate change is the imbalance of water resources availability between the wet and dry seasons. Both flood and drought events increasingly cause harm to human health, damage infrastructure, depleted groundwater aquifers, and impede socioeconomic development of entire rural-urban regions. Improving the resilience capacity of urban areas is seen as a sustainable solution to absorb and retain both rain and flood waters in natural lowlands and artificial reservoirs, combined with ecosystem-based adaptation solutions. Water retention structures are natural or engineered localities to balance the micro-climate, regulate the local water regime, create landscapes, and provide a source of freshwater during extended dry spells. This chapter summarizes lessons learned for water management and planners in adapting urban areas for future climate change. Using Ca Mau City, in the Vietnamese Mekong Delta, as a case study, we analyzed trends of increased urban flooding and drought occurrence in the wet and dry seasons, respectively. Finally, we propose a range of non-structural and structural solutions to strengthen the city’s overall resilience capacity. It is found that ecosystem-based projects that reduce both flood and drought risk and revive ecosystems are evidently workable and usually cost-effective and could be upscaled more broadly. However, the chief obstacles to implementing such initiatives are typically institutional and regulatory setups like the absence of horizontal and vertical integration in governance and the mono-disciplinary nature of policies and ordinances rather than technical ones.