Here are the solutions to Question 7.3:
7.3.1 A drainage pattern is the arrangement of streams and rivers in a drainage basin, which is influenced by the underlying geology, topography, and climate of the area.
7.3.2
- Drainage pattern A: Radial pattern
- Drainage pattern C: Rectangular pattern
7.3.3
- Drainage pattern B (Dendritic): Develops on homogeneous rock with uniform resistance to erosion, or on unconsolidated materials where there are no structural controls.
- Drainage pattern C (Rectangular): Develops on jointed or faulted bedrock where streams follow lines of weakness that intersect at approximately right angles.
7.3.4 In pattern A (Radial), the streams flow outwards from a central high point, such as a volcanic cone or a dome. The direction of flow is determined by the slope of the land, moving from higher elevation to lower elevation.
7.3.5 Drainage pattern B (Dendritic) is suitable for farming because it typically develops in areas with gentle slopes and uniform, often softer, underlying rock. Gentle slopes reduce soil erosion and allow for deep, fertile soil development, which is ideal for agriculture.
7.3.6 A drainage pattern that develops in a folded landscape is a Trellis pattern.
- Sketch description: Imagine a series of parallel main streams flowing in long, narrow valleys. Short, perpendicular tributaries join these main streams at nearly right angles, cutting across the resistant rock ridges.
- Labels: Main stream, tributary, ridge (or anticline), valley (or syncline).
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