Lesson Notes By Weeks and Term v4 - SHS 3
≈SUBSTRUCTURE AND SUPERSTRUCTURE
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≈SUBSTRUCTURE AND SUPERSTRUCTURE
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Applied Technology
Class: SHS 3
Term: 1st Term
Week: 16
Grade code: 3.3.2.LI.6
Strand code: 3
Sub-strand code: 3
Content standard code: 3.3.2.CS.1
Indicator code: 3.3.2.LI.6
Theme: BUILDING CONSTRUCTION TECHNOLOGY
Subtheme: ≈SUBSTRUCTURE AND SUPERSTRUCTURE
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Welcome, students. Every year during the rainy season, we hear news and see videos of flooding in places like Accra, Kumasi, and Takoradi. We see homes and roads submerged in water, causing damage to property and posing serious health risks. A major cause of this is the lack of, or failure of, proper drainage systems. In building construction, managing water on a site is one of the most critical tasks to ensure the building lasts long and the environment is safe. This lesson focuses on Surface Drainage Systems, which are the first line of defence against rainwater damage.
Teaching and Learning Activities: This section will be taught using a mix of direct instruction, visual aids (sketches on the board), and a "Think-Pair-Share" activity. For instance, after explaining the types of drains, students will be put into mixed-ability groups to discuss which types they have seen in their communities and why they think those were chosen. This aligns with the NaCCA GESI strategy of collaborative learning. A. What is a Surface Drainage System?
A Surface Drainage System is a network of channels, slopes, and structures designed to collect excess water (like rainwater or wastewater) from the surface of the ground and carry it away to a suitable disposal point, such as a larger municipal drain, a soakaway, or a nearby stream.
The main goal is to control surface runoff—water that flows over the land surface instead of seeping into the ground. If runoff is not controlled, it can lead to: Flooding: Water pooling around the building. Erosion: Washing away of topsoil. Foundation Damage: Water seeping into the ground near the foundation can weaken the soil and the foundation itself, causing cracks and structural failure. Health Hazards: Stagnant water becomes a breeding ground for mosquitoes (malaria) and can contaminate drinking water sources. B. Components of a Surface Drainage System A system typically has three main parts: Collection: This is where the water enters the system. It could be a grated inlet in a paved area or simply the open top of a gutter. Conveyance: This is the network that transports the water. It includes gutters, channels, pipes, and swales. Disposal: This is the final point where the water is discharged safely, away from the property. C. Types of Surface Drainage Systems
Here are the most common types you will encounter in Ghana and beyond. Open Drains / Channels (Gutters) These are the most common and visible type of surface drain in Ghana. They are open channels constructed on the ground surface. Description: They can be V-shaped, U-shaped (semi-circular), or rectangular in cross-section. Materials: Typically constructed from mass concrete, precast concrete sections, or sometimes just shaped earth in rural areas. How it works: They are built with a gentle slope (a gradient) so that gravity pulls the water along the channel to the disposal point. Ghanaian Context: These are the "gutters" we see along our roads and around houses. Advantages: Easy and relatively cheap to construct. Easy to inspect for blockages and to clean. Disadvantages: Can be a safety hazard (people can fall in). Often get clogged with rubbish, sand, and silt, requiring frequent cleaning. Can be breeding grounds for mosquitoes if water becomes stagnant.