Lesson Notes By Weeks and Term - Senior Secondary 1

TERM – 2^ND TERM

WEEK THREE

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Geography

Topic: LOWLANDS

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Explain and classify types of lowlands.
2. Explain the processes involved in the formation of different types of lowland.
3. Analyse the importance and effects of lowlands on man

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

LOWLANDS

Lowlands are typically describe areas of lower elevation, such as plains and coastal regions. These areas often have flatter terrain and may include valleys, basins, or coastal plains. Lowlands are contrasted with highlands or uplands, which are areas of higher elevation and often characterized by hills or mountains. Examples of lowlands include the Great Plains in North America and the Netherlands in Europe.

Types of lowlands

The following are types of lowlands:

1. Coastal Lowlands: Coastal lowlands are flat or gently sloping areas near coastlines. They often consist of plains or low-lying regions and can be influenced by both marine and terrestrial processes. These areas are susceptible to changes in sea level, tidal influences, and coastal erosion. Coastal lowlands are ecologically diverse and important for various habitats, including estuaries and wetlands.

Mode of formation

Coastal lowlands can form through various geological and environmental processes. Some common modes of formation include:

1. Depositional Processes: Sediments carried by rivers or ocean currents may accumulate along the coastline, forming low-lying areas.
2. Tectonic Activity: Subsidence or uplifting due to tectonic forces can create coastal lowlands. For instance, when a tectonic plate sinks (subsidence), it can form a basin or lowland near the coast.
3. Sea Level Changes: Fluctuations in sea level, such as during glacial-interglacial cycles, can influence the formation of coastal lowlands. During periods of lower sea levels, exposed land may become coastal lowlands.
4. Erosional Processes: Coastal lowlands can also result from erosion, where the action of waves, tides, and weathering gradually lowers the land level.

2. River Valleys: River valley lowlands refer to the relatively flat or gently sloping areas adjacent to the channel of a river within a river valley. These lowlands are shaped by the erosional and depositional processes of the river over time.

Mode of formation

River valley lowlands form through a combination of erosional and depositional processes driven by the flow of a river. Here's an overview of the mode of formation:

1. Erosion: The river erodes the landscape, cutting down into the Earth's surface through processes like hydraulic action, abrasion, and attrition. This downward erosion helps shape the V-shaped valley that characterizes many river valleys.
2. Meandering: As the river flows, it often develops meanders, which are bends or curves in its course. Lateral erosion on the outer bank of a meander and deposition on the inner bank contribute to the widening of the valley.
3. Floodplain Deposition: During floods, rivers overflow onto the surrounding floodplains. The water carries sediments, depositing them on the floodplain. This deposition contributes to the creation of flat, low-lying areas.

3. Plains: Plains are extensive, relatively flat or gently rolling areas characterized by low relief. They cover a significant portion of the Earth's surface and can be found on every continent. Plains can be classified into different types based on their formation and geographical location.

Mode of formation

Plains can form through a variety of geological processes. The mode of formation depends on factors such as tectonic activity, erosion, deposition, and climate. Here are some common modes of formation for different types of plains:

1. Alluvial Plains: Formed by the deposition of sediments carried by rivers, often in river valleys. Over time, the accumulation of fine-grained materials creates flat, fertile plains suitable for agriculture.
2. Coastal Plains: Result from the deposition of sediments along coastlines by rivers and ocean currents. The continuous input of sediment builds up these low-lying areas.
3. Interior Plains: May form due to tectonic processes, such as the uplifting or subsiding of the Earth's crust. Sedimentation and erosion play roles in shaping the topography of interior plains.

4. Basins: Basin lowlands refer to flat or gently sloping areas within geological basins. A basin is a large, bowl-shaped depression in the Earth's surface, often surrounded by higher elevations. Basin lowlands can take various forms depending on geological processes and the specific characteristics of the basin.

Mode of formation

Basins, which are large, bowl-shaped depressions in the Earth's surface, can form through various geological processes. The mode of formation depends on factors such as tectonic activity, erosion, and sedimentation. The following are some common modes of basin formation:

1. Tectonic Processes: Most basins are formed by tectonic activity, such as the subsidence of the Earth's crust. This can result from the stretching and thinning of the crust, leading to the formation of rift basins or from the sinking of large blocks of the crust, forming graben or half-graben basins.
2. Erosion and Sedimentation: Some basins can be created through erosion by rivers or glaciers, followed by the accumulation of sediments in a low-lying area. This process can lead to the development of sedimentary basins.
3. Impact Craters: Basins can also form as a result of high-velocity impacts from celestial bodies like meteorites or asteroids. These impact craters create bowl-shaped depressions, known as impact basins.
4. Volcanic Activity: Calderas, which are large, circular depressions formed by volcanic collapses, can act as basins. These depressions may fill with water to create volcanic caldera lakes.

Importance/effects of lowlands to Man

Lowlands, including river valley lowlands, coastal plains, and basin lowlands, hold significant importance for human societies. Here are some key aspects of their importance and effects:

1. Lowlands are often fertile areas, making them crucial for agriculture. River valley lowlands, in particular, with their nutrient-rich soils deposited during floods, provide ideal conditions for crop cultivation. Many civilizations historically settled in these areas to take advantage of fertile land for farming.
2. Lowlands, especially river valleys, have been attractive for human settlements due to their flat terrain, access to water for irrigation and transportation, and fertile soil for agriculture. Cities and towns often develop along rivers and in coastal plains.
3. Lowlands often offer convenient transportation routes. Rivers and coastal plains serve as natural transportation corridors, facilitating trade and communication. Many major cities are situated in lowland areas for better connectivity.
4. Lowlands support diverse ecosystems, including wetlands, floodplains, and coastal habitats. These areas are vital for biodiversity, providing habitats for various plant and animal species. Wetlands, in particular, act as nurseries for many aquatic organisms.
5. Lowlands may contain valuable natural resources such as minerals, fertile soils, and water. Coastal plains, for instance, can be rich in marine resources, supporting fisheries and aquaculture.

EVALUATION: 1. What is lowland?

2. Identify and discuss briefly the types of lowlands
3. Discuss the formation of plains.
4. Give 4 effects of lowlands to Man

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively