TERM: FIRST TERM
SUBJECT: BASIC SCIENCE
CLASS: JSS 3
REFRENCES
- BasicScience Made Easy for JSS Three by F.I Kehinde et al
- BasicScience Made Easy for JSS Two by F.I Kehinde et al
- STAN Integrated Science for JSS Three
- Precious Seeds Basic Science for JSS three by J.O Otugboyegaet al.
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WEEK TWO
TOPIC: FLOODING
CONTENT
- Introduction.
- Causes of Flooding.
- Factors that Affects Flooding.
- Consequences of Flooding.
- How to Control Flooding.�
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INTRODUCTION
Flood is a disastrous overflow of water from a lake or other body of water due to excessive rainfall or other input of water.�
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When there is heavy rain, so much water flows in=to the rivers that they come over the tops� of their banks and flood the land. This can be useful in many places as the flood carries a lot of silt into the flooded area thereby making that area very good for agriculture. However, if the floods are deep i.e., much, they can be harmful as they can destroy villages, etc.
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Controlling floods will involve taking risks. Since floods are natural.
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CAUSES OF FLOODING
- Heavy rain.
- Long periods of rain.
- Very wet saturated soil.
- Compacted or dry soil.
- Overflowing rivers.
- Lack of drainage system.
- Blocked drainages.
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EVALUATION
- What is flood?
- State four causes of flooding.
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FACTORS THAT DETERMINE OR AFFECT FLOODING
- The amount of water that runs off the wind.
- The amount of rainfall.
- The temperature.
- The type and condition of the soil.
- The amount and type of vegetation.
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CONSEQUENCES OF FLOODING
- Loss of lives and valuable properties.
- Destruction of crops.
- Loss of livestock.
- Widespread of waterborne diseases.
- Disruption of business activities.
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HOW TO CONTROL FLOODING
- By building dams�
- By building very high walls along the rivers banks to prevent it from overflowing its banks.
- By widening the rivers.
- By building reservoirs to hold more water during flooding.
- Streams may be diverted so that they do not flow into a particular river and result to flooding.
- Irrigation
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EVALUATION�
- State four consequences of flooding.
- State four factors that leads to flooding.
- State fours way to control or manage flooding.
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SOIL EROSION
Soil erosion is the wearing away and loss of soil from an area. Soil erosion is the washing away of soil by heavy rain or wind resulting in formation of gulley and landslides and leaving behind barren rocks and slits on which plants can no longer grow. Soil erosion poses serious to agriculture as it wash away the nutrient from the topsoil.
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TYPES OF EROSION
Based on the cause of erosion, we have:
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Water erosion: This is the erosion caused as a result of heavy rainfall or flood which wash away the soil on slopes. Constant flow of water create gullies over a long time. When rain falls on sloppy ground the water runs off thereby washing away a large portion soil and also breaking down rocks in a process called weathering.
Wind erosion: This the erosion caused by fast moving wind which exposes the top soil and carry them away. Wind erosion can be controlled by planting trees along the wind path. These trees serve as windbreaker
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HUMAN ACTIVITIES THAT CAUSE EROSION
Burning of bush: The deliberate or accidental burning of bush destroys the soil structure and exposes it to erosion and high temperature.
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Farming: The cutting of trees and clearing of farmlands exposes the soil to erosion
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Building of house and industries: The clearing of land before the building of houses promote erosion.�
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Growth of town: Development of town leads to the exposure of the soil surfaces which can easily be washed away.
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Construction of roads: The construction of new road leads to the breaking of soil structure which make it easy for soil to be washed away.
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EFFECTS OF EROSION
- It reduces soil fertility.
- It damages road and soil surfaces.
- It destroys farmland and farm produce.
- It may lead to lose of buildings.
- It leads to loss of lives through accident and building collapse.
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CONTROL OF EROSION
- Indiscriminate burning of bushes should be stopped.
- Plant of trees and cover crops.
- The practice of mulching in which cut grass residue are spread over the soil surface under a growing crop which retains moisture, reduces weeds and prevent exposure of the soil surface thereby reducing soil erosion.
- Construction of terraces on sloppy land.
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METHODS OF PREVENTING SOIL EROSION
- Wind erosion can be prevented by planting cover crops, grasses and belt of trees which serves as wind breakers.
- Water erosion and flooding can be prevented through proper canals and drainage channels to lead water away in to rivers.
- Gully erosion can be stopped by small dams with stones and sticks along the gullies in order to capture soil that is being washed away.
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- Terrace should be build to prevent erosion. Terraces are barriers constructed along contours of the land which hinders the rapid flow of water down the slopes.
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GENERAL EVALUATION
- What is flood?
- What are the activities of man that contributes to flooding?
- What is power?
- What is puberty?
- Explain what you understand by "teetotalism"
- What is pregnancy?
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READING ASSIGNMENT
Basic Science Made Easy for JSS Three by F.I. Kehinde et al. Chapter 5. Pages 15-16
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WEEKEND ASSIGNMENT
- The overflowing of rivers as a result of continuous rainfall leads to��
- erosion� B. deforestation� C. flooding� D. drought
- Which of the following will help to control flooding?� A. Overgrazing
- Deforestation� C. Damming of rivers� D. Dumping of refuse
- Which of the following does not contribute to flooding?
- Blocked drainages� B. Overflowing rivers� C. Adequate drainage system
- Loss of lives
- Which of the following is a consequence of flooding?� A. Growth and development � B. Increased fertility� C. Destruction of livestock� D. Provision of food
- Flood is a ___ occurrence.� A. natural� B. Man-made� C. Phenomenal
- Economical
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THEORY
- List five things you can do to prevent flooding in your immediatel environment.
- What are the environmental and economic impacts of flooding?
- Mention five ways to prevent erosion?
