*WAEC GCE GEOGRAPHY PRACTICAL*
(i) Hydraulic action
(PICK ANY FOUR)
(i) Wide and flat valley: As the river approaches its mouth, the valley widens and flattens, creating a broad floodplain.
(ii) Meanders: The river forms large bends called meanders as it flows through the flat valley. This is due to the lower gradient and slower flow of water.
(iii) Oxbow lakes: Over time, meanders can erode through adjacent land, cutting off a loop of the river and forming an oxbow lake.
(iv) Delta: In the lower course, where the river meets a body of water, such as a lake or the ocean, it may form a delta. A delta is a triangular-shaped deposit of sediment that builds up over time.
(v) Slower flow: The gradient of the river decreases in the lower course, resulting in a slower flow of water.
(vi) Increased deposition: Due to the reduced flow velocity, the river loses its ability to carry sediment, leading to increased deposition of sediment on the floodplain and in the delta.
(PICK ANY TWO)
(i) Coriolis effect: The rotation of the Earth causes moving air and water to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This effect influences global wind patterns and ocean currents.
(ii) Day and night cycle: The rotation of the Earth on its axis causes the alternation between day and night. This cycle of sunlight and darkness affects the temperature and biological activities on Earth.
(iii) Formation of tides: The gravitational pull of the moon and the rotation of the Earth cause the formation of ocean tides. As the Earth rotates, the gravitational forces change, resulting in the rise and fall of sea levels.
(iv) Geostrophic wind flow: Due to the rotation of the Earth, the balance between the pressure gradient force and the Coriolis effect results in the formation of geostrophic winds, which are large-scale horizontal winds found in the upper atmosphere.
(i) Rock pedestal: A rock pedestal forms through the process of differential weathering and erosion. It starts with a large rock formation that is exposed to different weathering agents, such as wind, water, and ice. These agents gradually erode the rock formation, but they do not erode the entire rock at the same rate. Certain parts of the rock are more resistant to erosion compared to others. As a result, these resistant parts remain standing while the surrounding rock erodes away. Over time, this differential erosion creates a rock pedestal, where a smaller and narrower column of rock is left standing on a wider base. This pedestal can take on various shapes depending on the type of rock and the specific erosional processes involved. Some rock pedestals may have a mushroom-like appearance, with a larger cap on top and a narrower stem at the base. Others may have a more columnar or conical shape. The formation of rock pedestals is commonly observed in areas with soft or layered rock formations, such as sandstone, limestone, or shale.
(ii) Stack: A stack is formed through a combination of weathering, erosion, and wave action in coastal areas. It starts with a headland, which is a rocky promontory projecting into the sea. The waves continuously crash against the base of the headland, undercutting and weakening the rock. Over time, this process of hydraulic action, abrasion, and corrosion causes the rock to erode and form a wave-cut notch at the base of the headland. Eventually, the notch becomes deeper and wider, resulting in the collapse of the upper part of the headland. The detached rock mass then forms a stack, which is a vertical column of rock standing separately from the headland. Stacks can vary in height and shape depending on the geological characteristics of the area. While they are initially connected to the mainland, stacks are often found in clusters or are eventually separated by further erosion, forming isolated sea stacks.
Mass wasting refers to the downslope movement of a mass of rock, soil, or debris under the influence of gravity. It is a natural geological process that occurs continuously, resulting in the gradual erosion and shaping of landforms.
(PICK ANY FOUR)
(i) Steep slope gradients: Steeper slopes have weaker stability and are more prone to mass wasting. Gravity has a stronger pull on materials on steep slopes, increasing the likelihood of movement.
(ii) Saturation of the material: When the soil or rock becomes saturated with water, it loses its strength and cohesion, making it easier for gravity to overcome the frictional forces holding it in place.
(iii) Weathering and erosion: The process of weathering weakens the composition of rocks and soil, making them more susceptible to mass wasting. Erosion also removes support from lower layers, making them more prone to movement.
(iv) Presence of weak or loose material: Loose soils, such as clay and silt, or weak rocks, like shale, are more likely to experience mass wasting due to reduced stability and a higher potential for internal movement.
(v) Earthquakes and seismic activity: Vibrations from earthquakes and other seismic activities can trigger mass wasting by shaking or destabilizing the material, causing it to slide or slump.
(vi) Human activities: Construction, excavation, deforestation, and other human activities can alter the natural slope stability, removing vegetation cover, altering drainage patterns, and creating weaknesses in the landscape, leading to increased susceptibility to mass wasting.
(PICK ANY TWO)
(i) Property damage and infrastructure destruction: Mass wasting can damage or destroy buildings, roads, bridges, and other infrastructure, leading to financial losses and disruption of communities.
(ii) Loss of life and injury: Mass wasting events can be sudden and unexpected, causing fatalities, injuries, and displacing people from their homes.
(iii) Geological hazards: Mass wasting can create geological hazards, such as landslides or mudslides, which can block rivers and streams, leading to flooding and the downstream destruction of ecosystems and habitats.
(iv) Soil erosion: Continuous mass wasting can result in the loss of fertile topsoil, which is essential for agriculture and vegetation growth. This can lead to reduced agricultural productivity, soil degradation, and decreased biodiversity.
(6a) A lake is a large body of water, typically freshwater, surrounded by land.
(6b) An ox-bow lake forms when a meandering river creates a cutoff, isolating a bend or loop of the river. Over time, sedimentation and natural processes lead to the formation of a curved lake resembling the shape of an ox-bow.(check image)
(i) Freshwater Supply: Lakes serve as vital sources of freshwater for human consumption, agriculture, and industrial processes.
(ii) Biodiversity Support: Lakes contribute to biodiversity by providing habitats for diverse plant and animal species, playing a crucial role in ecological balance.
(iii)Recreational Opportunities: Lakes offer recreational activities such as fishing, boating, swimming, and camping, enhancing the quality of life for local communities.
(iv)Economic Significance: Lakes have economic value through tourism, attracting visitors and supporting industries like fishing, contributing to local economies and livelihoods.
(PICK ANY THREE)
(i) Sahara Desert in North Africa
(ii) Arabian Desert in the Arabian Peninsula
(iii) Mojave Desert in the southwestern United States
(iv) Atacama Desert in Chile
(v) Gobi Desert in Mongolia and China
(PICK ANY FIVE)
(i) High temperatures: Hot deserts are characterized by extremely high temperatures, often reaching above 100 degrees Fahrenheit (38 degrees Celsius) during the day.
(ii) Low humidity: Deserts have very low levels of humidity, which means that the air is dry.
(iii) Scarce rainfall: Hot deserts receive very little rainfall, often less than 10 inches per year. This lack of rain contributes to the arid conditions.
(iv) Wide temperature fluctuations: Deserts experience significant temperature variations between day and night. While the days are scorching hot, the nights can be freezing cold.
(v) Strong winds: Deserts are known for their strong winds that can cause sandstorms and erosion. These winds can further contribute to the dryness and harshness of the climate.
(PICK ANY THREE)
(i) Deep root systems: Desert plants often have extensive root systems that reach deep into the ground to access water sources deep below the surface.
(ii) Succulent leaves and stems: Some desert plants store water in their leaves or stems, which helps them survive during extended periods of drought.
(iii) Protective structures: Many desert plants have adaptations such as thorns, spines, or tough, waxy outer coverings to protect themselves from predators and reduce water loss through evaporation.
(iv) Reduced leaf surface area: Desert plants often have small, needle-like leaves or no leaves at all. This helps to minimize water loss through transpiration.
(v) CAM photosynthesis: Some desert plants use Crassulacean Acid Metabolism (CAM) photosynthesis, which allows them to take in carbon dioxide at night and store it for use during the day. This reduces water loss by limiting their need to open their stomata in the heat of the day.
(PICK ANY FIVE)
(ii) Surface water
(vi) Sea and ocean water
(PICK ANY FIVE)
(i) Pollution: Industrial and agricultural activities release pollutants into water bodies, making the water unsafe for human consumption or other uses.
(ii) Deforestation: Clearing forests can lead to soil erosion, which affects the quality and availability of water by increasing sedimentation in rivers and lakes.
(iii) Overuse and depletion of groundwater: Excessive pumping of groundwater for agriculture, industry, and domestic use can deplete underground water sources, leading to a decrease in availability for future use.
(iv) Damming rivers: Construction of dams disrupts the natural flow of rivers, affecting ecosystems, and altering water availability downstream.
(v) Climate change: Changes in weather patterns and the increasing frequency of droughts and floods can negatively impact water availability and quality.
(vi) Inefficient water management: Poor water management practices, including inefficient irrigation methods and inadequate maintenance of water infrastructure, can result in wasted water and limited access to clean water for communities.