El Niño and La Niña Cycles: The 2016-2017 floods were mostly attributed to the La Niña phenomenon which resulted in a combination of heavy rainfalls and tropical cyclonic activity. It followed the 2015–2016 El Niño phenomenon which resulted in reduced rainfall and drought. This transition from severe drought conditions to excessive wet conditions led to rapidly saturated grounds.[1]
Tropical Cyclones: In February 2017, the tropical cyclone Dineo which originated from the Mozambique Channel in the Indian Ocean, hit the southeastern cost of Mozambique on the 15th of February with winds exceeding 100km/hr. Originally a category 3 tropical cyclone according to MTOTEC, it downgraded to a tropical depression as soon as it made landfall in Mozambique and was reclassified as Ex-Dineo.[2] It continued its trajectory westwards and penetrated inland reaching Zimbabwe on the 16th of February and exacerbated the weather conditions as it brought heavy rains and strong winds with more than 100mm of rain in 24 hours.[3]
Topography: The center part of Zimbabwe consists of a high broad plateau called the Highveld situated approximately 1200m above sea level and forming a watershed with lower regions on either side of it sloping into the Zambezi River basin to the north, the Limpopo River basin to the south, and the Save River basin to the southeast which make low-lying regions more prone to flooding.[4]
Soil: About 70% of the soil consists of granite-derived sandy soils which are susceptible to degradations such as leaching and erosion under heavy rains.[5]
Rivers and Dam Systems: Because of the La Niña phenomenon, most rivers and their tributaries had already received above-average rainfall, and the grounds were already saturated leading to surface runoff. The tropical cyclone Dineo made the situation worse resulting in 85% of the country’s dams that could not sustain the excessive amount of extra water and spilled over exacerbating the flooding situation.[1][6]
Infrastructure: Infrastructures such as dams, roads, bridges, or homesteads were prone to damage during heavy rains, because they were old or outdated, or built with non-durable or poor-quality construction materials, so they lacked the robustness to withstand such high volumes of water.[7]
Population Distribution: More than 70% of the population relies on agriculture as their primary source of income.[8] They reside in low-lying rural regions near rivers which are highly vulnerable to flooding.[9]
Deforestation and Soil Degradation: Deforestation activities and soil degradation from farming, have made the country susceptible to floods by weakening the natural ability of trees to absorb water and reducing the soil’s water retention capacity.[10]
Disaster Preparation and Risk Management Strategies
Early Warning Systems: Early warning systems and information dissemination were insufficient because it failed to reach the most vulnerable population in remote rural areas which often do not have access to newspapers, television, radio, or telephones.[11][12][13][14]
Community Preparedness: Many rural communities lacked knowledge on flood risks, or on how to be prepared and react in case a flooding occurred, and on evacuation protocols making them vulnerable. This was mainly due to lack of education and lack of governmental campaigns.[7]
Disaster Response: The Government was not prepared and poorly equipped to properly respond to such a large-scale disaster due to its lack of funding, workforces, resources, and its inability to implement climate change strategies.[11][12]
Aid Dependence: Due to its financial difficulties and limited resources to manage such a catastrophe, Zimbabwe needed to rely on international and humanitarian help.[12][14][15]
^Gotore, T., Muchawona, A., Murepa, R., Tembani, M., Mutete, P., Muchena, R. and Mujuru, L., 2019. Drivers of deforestation and forest degradation in Zimbabwe. STZNDC Report: Government of Zimbabwe/UNDP.
