Question 1: Describe the process of river erosion and explain how it contributes to the formation of a river valley.

Answer: River erosion involves processes such as hydraulic action, abrasion, and attrition, which wear away the riverbed and banks. Over time, these processes deepen and widen the valley, forming features like a V-shaped valley in the upper course of a river.

Question 2: Identify and explain three main types of river transportation. Provide an example of how each occurs in a river system.

Answer: The three main types are traction (large particles rolling along the riverbed), saltation (particles bouncing along), and suspension (fine particles carried within the water). For example, boulders are moved by traction, pebbles by saltation, and silt by suspension.

Question 3: Explain the formation of a waterfall, including the role of different rock types and erosion processes.

Answer: A waterfall forms where a river flows over resistant rock overlaying softer rock. The softer rock erodes faster due to hydraulic action and abrasion, creating a steep drop. Over time, the undercutting causes the hard rock to collapse, maintaining the waterfall's formation.

Question 4: Describe the features of the middle course of a river and how they differ from the upper and lower courses.

Answer: The middle course features a wider, deeper channel, with more gentle gradients. It often includes features like meanders and floodplains. Unlike the steep, narrow upper course and the broad, depositional lower course, the middle course is characterized by lateral erosion and transportation.

Question 5: Define what a floodplain is and explain how it forms through river processes.

Answer: A floodplain is a flat area of land on either side of a river that floods periodically. It forms through lateral erosion and deposition during flood events, which gradually builds up the flat, fertile area.

Question 6: Draw a cross-section of a river showing the features typical of the upper, middle, and lower courses. Label the features clearly.

Answer: A correct sketch should show a cross-section with a steep, narrow upper course with features like a V-shaped valley and waterfalls; a wider, more meandering middle course with floodplains and oxbow lakes; and a broad, flat lower course with a delta or estuary. Label features such as valley, meander, floodplain, and delta.

Question 7: Explain the difference between a delta and an estuary, including how each forms and their key features.

Answer: A delta is a landform at the mouth of a river where it deposits sediment, forming a triangular or fan-shaped area. An estuary is a tidal mouth of a river where freshwater mixes with seawater, leading to a brackish environment. Deltas form through deposition in low-energy environments, while estuaries result from tidal processes and river flow.

Question 8: Identify two human activities that can impact river systems negatively and explain their effects.

Answer: Urbanization increases runoff and pollution, leading to increased flooding and water quality issues. Deforestation reduces vegetation cover, increasing erosion and sedimentation in rivers, which can cause blockages and habitat loss.

Question 9: Describe how a hydroelectric dam can affect the physical features of a river and its surrounding environment.

Answer: A hydroelectric dam creates a reservoir, flooding upstream areas and creating a new lake. It reduces downstream flow, affecting erosion and sediment transport, and can disrupt habitats and ecosystems both upstream and downstream.