SAJC Cluster 2.2 Lecture 14 Notes (Fluvial Landforms)

St Andrew’s Junior College H2 Cluster 2: Tropical Environments H2_Cluster 2 Lecture 14_2025/pg1 Lecture 14 Fluvial Landforms (I): Meanders and Braided Channels KEY QUESTIONS: ✓ How do natural processes and human activities influence landforms in the humid tropics? With the completion of this lecture, attached readings and tutorial, you should be able to understand: • the fluvial landforms found in the humid tropics like meanders and braided channels • the features of meanders and braided channels • the factors that influence the formation of meanders and braided channels in the humid tropics Lecture Outline 14.1 Introduction: Fluvial Landforms 14.2 Meanders 14.2.1 Features of a Meander 14.2.2 Conditions Necessary for the Formation of Meanders 14.2.3 Formation of Meanders 14.3 Braided Channels 14.3.1 Features of Braided Channels 14.3.2 Conditions Necessary for the Formation of Braided Channels 14.3.3 Formation of Braided Channels 14.4 Factors Influencing the Formation of Meanders and Braided Channels 14.5 Conclusion

St Andrew’s Junior College H2 Cluster 2: Tropical Environments H2_Cluster 2 Lecture 14_2025/pg2 14.1 Introduction: Fluvial Landforms • Present-day landforms are shaped by processes that have operated over very long timescales. These processes work together to shape the earth’s surface, creating landforms that contribute to the splendor of the natural environment. As humans continue to build settlements in the natural environments, these landforms are impacted by human activities. • Although in our syllabus we have three fluvial landforms namely meanders, braided channels (see Lect.14) and deltas (see Lect.15), in this lecture, we will examine fluvial landforms in the humid tropics. Specifically, we will build our understanding of what meanders and braided channels are. We should be able to describe and sketch meanders and braided channels. We will also seek to determine the relative importance of natural and human factors in the formation of these two fluvial landforms. Box 1: Important Terms The course of a river is conceptually divided into 3 parts, upper, middle and lower. Although erosion, transportation and deposition happen throughout the course, their rates change over the course of a river. a) Long Profile of a River: The long profile shows how a river’s gradient changes as it flows from its source in its upper course to its mouth in the lower course. A long profile is usually concave and the slope becomes more gentle towards the mouth of the river. b) Cross Profile: A cross profile shows a cross-section of a river’s channel and valley at a certain point along the riv