Year 10 IGCSE Geography Comprehensive Study Notes (2025-2026)

INTRODUCTORY GEOGRAPHY AND COURSE OVERVIEW

• Institution: CAPLORA STEM INTERNATIONAL SCHOOL.

• Subject: Geography (0460).

• Academic Year: 2025-2026 (Year 10).

• Instructor: Tr. Claire.

• Types of Geography Listed:     * Human Geography Fields: Behavioral, Cultural, Rural, Economic, Urban, Population, Medical, Political.     * Physical Geography Fields: Climatology, Soils, Geomorphology, Hazards, Geodesy, Hydrology, Biogeography.     * Technical/Methodological Fields: GIS (Geographic Information Systems), Statistics, Cartography, Regional, Remote Sensing, Image Processing.

• Geographical Themes: Physical Geography and Natural Geography.

UNIT 1: CHANGING RIVER ENVIRONMENTS

• Definition of a River: A large natural stream of water flowing in a channel to the sea, a lake, or another river (e.g., "the River Danube").

• Definition of a Drainage Basin: An area of land where all precipitation and surface water drain downhill into a common outlet, such as a river, lake, or ocean.

• Major Rivers of the World:     * North America: Mackenzie, Missouri, Arkansas, Colorado, Ohio, St. Lawrence, Rio Grande, Mississippi.     * South America: Amazon, Paraguay, São Francisco, Paraná, Uruguay.     * Europe: Volga, Dnipro, Rhine, Ural, Danube, Don.     * Africa: Niger, Nile, Blue Nile, White Nile, Congo, Orange, Zambezi.     * Asia: Yenisey, Ob, Lena, Amur, Yarlung Tsangpo, Huang He (Yellow River), Yangtze, Ganges, Indus, Mekong, Brahmaputra.     * Oceania: Murray, Darling.

• Key Features of a River Basin:     * Channel: The main path where the water flows.     * Source: The start of a river.     * Mouth: The point where the river meets the sea or a lake.     * Tributary: A smaller stream or river that joins a larger one.     * Confluence: The point where two rivers or streams meet.     * Watershed: The boundary separating one drainage basin from another.

• Long Profile of a River:     * Upper Course: Source, steep gradient.     * Middle Course: Gentle gradient.     * Lower Course: Very gentle gradient, leading to the mouth.

• Hydraulic Characteristics and Stream Efficiency:     * Channel Efficiency: Defined by the relationship between cross-sectional area and the wetted perimeter.     * Stream A (High Efficiency): Cross-section Area = $40\,m^2$. Wetted perimeter (Width $8\,m$ + Depth $5\,m$ + Depth $5\,m$) = $18\,m$. Hydraulic Radius = $\frac{40}{18} = 2.22\,m$. Low relative friction.     * Stream B (Low Efficiency): Cross-section Area = $40\,m^2$. Wetted perimeter (Width $20\,m$ + Depth $2\,m$ + Depth $2\,m$) = $24\,m$. Hydraulic Radius = $\frac{40}{24} = 1.66\,m$. High friction.

• The Bradshaw Model: A geographical diagram showing how river characteristics change from source to mouth.     * Characteristics that Increase Downstream: Discharge, Occupied channel width, Water depth, Water velocity, Load quantity.     * Characteristics that Decrease Downstream: Load particle size, Channel bed roughness, Slope angle (gradient).

THE HYDROLOGICAL CYCLE AND RIVER PROCESSES

• The Water Cycle (Hydrological Cycle): The continuous journey water takes on, above, and below Earth's surface, moving through liquid, solid, and gas states. Driven by the sun’s energy.

• Processes and Labels:     1. Direct evaporation (E): Of intercepted precipitation.     2. Transpiration (T): Water released by plants.     3. Precipitation (P): Rain, snow, etc.     4. Channel Precipitation (CP): Water falling directly into the river.     5. Infiltration (I): Water soaking into the soil.     6. Surface Run off (Overland Flow - OF): Very fast movement over land.     7. Throughflow (TF): Quick movement through soil above the water table.     8. Percolation: Deep movement into rock.     9. Groundwater flow (GWF): Slow baseflow through saturated rock.     10. Water Table: The zone separating the Aeration Zone from the Saturation Zone.

• Erosion Types:     * Vertical Erosion: Downward cutting, dominant in the upper course.     * Lateral Erosion: Sideways cutting, dominant in the middle and lower courses.

• Transportation Methods:     * Suspension: Small particles like silt and clay carried within the water.     * Solution: Minerals dissolved in the water.     * Traction: Large boulders rolled along the river bed.     * Saltation: Small pebbles and stones bounced along the river bed.

• Deposition: Occurs when a river loses energy.     * Order of Deposition by size: Boulders (> 256\,mm) → Cobbles ($64 - 256\,mm$) → Pebbles ($2 - 64\,mm$) → Sand ($0.0625 - 2\,mm$) → Silt ($0.002 - 0.0625\,mm$) → Clay (< 0.002\,mm).

FLOODING, MANAGEMENT, AND POLLUTION

• Opportunities of Rivers: Irrigation, hydropower, livelihoods (fisheries/agriculture), commercial transport, recreation, and ecosystem services. Examples: Nile, Amazon, Yangtze, Mississippi, Colorado.

• Causes of Flooding:     * Natural/Physical: Geology (impermeable rock), Steep Relief, Saturated ground, Drainage density, Catchment size/shape, Meteorological conditions (heavy rain/snowmelt), lack of Vegetation.     * Human: Urbanisation (impermeable surfaces), Bad Farming Practices (bare fields, soil compaction), Deforestation (loss of soil "sponge").

• River Management Strategies:     * Hard Engineering: Dams/reservoirs, Channel straightening, Embankments/levees, Flood relief channels, Dredging. Pros: High protection levels; Cons: Expensive, disruptive to ecosystems.     * Soft Engineering: Planting trees (Afforestation), Flood prediction/warnings, Floodplain zoning, River restoration, Washlands/meander restoration. Pros: Sustainable, cheaper; Cons: Requires more land.

• River Pollution:     * Context: Cleanup project grant of 10,000\,\ for the Nairobi River.     * Sources: Industrial waste, domestic sewage, agricultural runoff.

UNIT 2: CHANGING HUMAN POPULATIONS

• Key Dynamics:     * Fertility Rate: Average number of children a woman has.     * Birth Rate (BR) / Death Rate (DR): Number of births/deaths per $1000$ people per year.     * Natural Increase: BR − DR.     * Migration: Movement of people (Emigration vs. Immigration).

• Demographic Transition Model (DTM) Stages:     * Stage 1 (High Stationary): High BR, High DR, Stable pop. (e.g., remote groups).     * Stage 2 (Early Expanding): High BR, Rapidly falling DR, Rapid increase. (e.g., Niger, Egypt, Kenya, India).     * Stage 3 (Late Expanding): Falling BR, Slowly falling DR, Slowing increase. (e.g., Brazil, Morocco).     * Stage 4 (Low Stationary): Low BR, Low DR, Stable/Slow increase. (e.g., USA, Japan, France, UK, Australia).     * Stage 5 (Declining): Very low BR, Low DR, Natural decrease. (e.g., Germany).

• Population Policies:     * Anti-Natalist: China's "One Child Policy" (Late, Sparse, Few); Kerala, India (Focus on female education, healthcare, land reform).     * Pro-Natalist: France (Positive attitudes toward 2-3 child families); Germany (Incentives for parents to counter birth rate of $1.38$ in 2012).

• Overpopulation vs. Underpopulation:     * Overpopulation (e.g., Nigeria): Housing shortage, pollution, food/water shortage, high crime, lack of healthcare/jobs.     * Underpopulation (e.g., Australia): Worker shortage, low production, resources underused, high taxes, small market.

• Migration Types:     * Economic Migrant: Seeking jobs/better living.     * Refugee / Asylum Seeker: Fleeing war/persecution.     * Push Factors: War, poverty, disasters, lack of food.     * Pull Factors: Better healthcare, peace, money, jobs, education.     * Global Stats (2025 Prediction): World migrants: $304\,million$ ($48\%$ female). Africa: $61.2\,million$. Northern America: $29.2\,million$. Europe: $92.2\,million$.

• Population Density Calculation: $\text{Total Population} / \text{Total Area (km}^2\text{)} = (x)\text{ people per km}^2$.

UNIT 3: CHANGING COASTAL ENVIRONMENTS

• Coastal Processes:     * Erosion: Hydraulic action, Corrosion, Corrasion (Abrasion), Attrition.     * Waves:         * Constructive: Low frequency, strong swash, weak backwash, builds up beach.         * Destructive: High frequency, weak swash, strong backwash, removes material.     * Longshore Drift: Movement of sediment along the coast determined by prevailing wind and swash/backwash direction.     * Wave Refraction: Bending of waves as they enter shallow water, concentrating energy on headlands.

• Coastal Landforms:     * Erosion: Headlands and Bays (discordant coastlines), Caves → Arches → Stacks → Stumps, Cliffs and Wave-cut platforms.     * Deposition: Beaches (Backshore, Berm, Foreshore, Nearshore, Offshore), Spits, Bars, Tombolos (joining island to mainland), Sand Dunes.

• Coastline Types:     * Discordant: Alternating bands of hard and soft rock at right angles to the sea.     * Concordant: Single band of rock type running parallel to the sea.

UNIT 4: CHANGING ECOSYSTEMS

• Antarctica (The Cold Desert):     * Location: Southern hemisphere, centered on the South Pole, within the Antarctic Circle ($66.6^\circ S$).     * McMurdo Station Climate Data: Lat $77.88^\circ S$; Long $166.73^\circ E$. Elevation $24\,m$ ($78\,feet$). Annual Mean Temp: $-16.9^\circ C$. Annual Total Precip: $202.5\,mm$. Max month March ($24.1\,mm$).     * Reasons for Cold: Axial Tilt ($23.5^\circ$), Low angle of insolation (heat spread over large area), Sinking cold air (High Pressure).     * Biotic Factors:         * Flora: Algae (Bri), Lichenos (Jibril), Mosses (Gina), Pearlwort (Don).         * Fauna: Seals (Lind), Orca (Do), Snow petrels, Krill (Dey, Bin), Penguins, Whales (Railey), Skua (Damia).     * Management: The Antarctic Treaty System, International Legal Frameworks, Scientific Coordination.

• Tropical Rainforests (TRF):     * Distribution: Equatorial (between Tropic of Cancer $23.5^\circ N$ and Capricorn $23.5^\circ S$).     * Climate characteristics: Overhead sun, low pressure, convectional rainfall.     * Structure: 1. Emergent layer (tallest trees), 2. Canopy (biodiverse roof), 3. Understorey (dark/humid), 4. Forest floor (nutrient-poor soil).     * Nutrient Cycle (Gersmehl): Biomass → Litter → Soil. Cycles influenced by Fallout, Leaching, Run off, and Uptake.