SAJC Cluster 2 Lecture 8 Notes (Impacts of Fluvial Floods on Places)

St Andrew’s Junior College H2 Cluster 2: Tropical Environments H2_Cluster 2 Lecture 8_2024/pg1 Lecture 8 Floods in the Humid Tropics (II): Impacts of Fluvial Floods on Places KEY QUESTION: ✓ Why do fluvial floods affect places and people differently? With the completion of this lecture, attached readings and tutorial, you should be able to understand the: • Impacts of fluvial floods on places • Variations in the effects of fluvial floods on places • Variations in effects of fluvial floods experienced by different groups of people due to differences in their vulnerability to fluvial floods Lecture Outline 8.1 Introduction: Impacts of Fluvial Floods 8.2 Positive Impacts 8.2.1 Increase soil fertility 8.2.2 Recharge ground water storage 8.3 Negative Impacts Economic 8.3.1 Property damages and economic losses Environmental 8.3.2 Extreme floods cause erosion Environmental and Economic 8.3.3 Destruction of agricultural land Social 8.3.4 Loss of lives, and post-trauma stress 8.3.5 Diseases 8.4 Different Groups of People, Different Vulnerabilities

St Andrew’s Junior College H2 Cluster 2: Tropical Environments H2_Cluster 2 Lecture 8_2024/pg2 8.1 Introduction: Impacts of Fluvial Floods • Fluvial floods, often triggered by heavy rainfall and snowmelt, have profound and multifaceted impacts on both natural environments and human communities. • The consequences of fluvial floods encompass a wide spectrum, ranging from immediate and devastating damage to infrastructure, property, and livelihoods, to more intricate ecological effects such as soil erosion, sediment deposition, and alterations to aquatic ecosystems. • As the frequency and intensity of extreme weather events continue to rise due to climate change, understanding and mitigating the impacts of fluvial floods have become essential endeavors for sustainable development and disaster resilience. 8.2 Positive impacts • Fluvial floods, though often associated with destruction and disruption, can also bring about a range of positive impacts that contribute to the ecological health and vitality of river systems and surrounding landscapes. 8.2.1 Increase soil fertility • Perhaps, one of the most recognised benefits of flooding is that it makes the soil fertile. o As the flood water eventually recedes, it leaves behind fine sand, clay, silt and organic matter. Floodwaters transport nutrients and sediments to floodplains, which nourish the soil. This aids in the distribution and deposition of river sediments across broad floodplains. o The nutrients in the topsoil are replenished by these river sediments, making agriculture more productive. Since recurrent flooding resulted in fertile, productive farmland, many ancie