NECTA Form Six Geography 1
Common Physical Geography Questions & Detailed Solutions
NECTA Geography 1 Assessment Objectives
The National Examinations Council of Tanzania (NECTA) designs Form Six Geography 1 examinations to assess students' comprehensive understanding of physical geography concepts, processes, and their interrelationships. The examination focuses on developing spatial awareness, environmental understanding, and analytical skills essential for interpreting the physical world and human-environment interactions.
Core Assessment Objectives
1. Geographical Knowledge & Understanding
Demonstrate comprehensive knowledge of physical geography concepts including geomorphology, climatology, hydrology, biogeography, and pedology. Students must understand Earth's structure, atmospheric processes, water cycles, landform development, and ecosystem dynamics.
2. Process Understanding & Analysis
Analyze and explain geographical processes such as plate tectonics, weathering, erosion, atmospheric circulation, hydrological cycles, and ecosystem succession. Students should understand cause-effect relationships and spatial patterns in physical phenomena.
3. Map Interpretation & Spatial Skills
Interpret topographic maps, weather maps, and thematic maps. Calculate gradients, bearings, distances, and interpret relief features. Analyze spatial patterns and relationships using map evidence.
4. Data Analysis & Fieldwork Skills
Analyze geographical data presented in various formats (tables, graphs, diagrams). Demonstrate understanding of fieldwork techniques, data collection methods, and geographical investigation processes.
5. Environmental Systems Understanding
Understand the interrelationships between atmospheric, lithospheric, hydrospheric, and biospheric systems. Analyze how changes in one system affect others and impact human activities.
6. Application to Tanzanian Context
Apply geographical knowledge to Tanzania's physical environment - its landforms, climate patterns, drainage systems, vegetation types, and environmental challenges. Relate global processes to local manifestations.
Specific Content Areas Assessed
Geomorphology & Geology
• Earth's structure and internal processes • Plate tectonics theory • Folding, faulting, vulcanicity • Weathering processes • Mass wasting • Fluvial, glacial, aeolian, coastal processes • Landform development • Tanzania's major landforms
Climatology & Meteorology
• Atmospheric structure and composition • Solar radiation and heat balance • Atmospheric pressure and winds • Humidity and precipitation • Air masses and fronts • Climate classification • Climate change • Tanzania's climate zones
Hydrology & Oceanography
• Hydrological cycle • River systems and drainage basins • Lakes and wetlands • Groundwater • Ocean currents and tides • Coastal processes • Water resource management • Tanzania's drainage systems
Biogeography & Pedology
• Ecosystem structure and function • Biomes and vegetation zones • Soil formation processes • Soil profiles and classification • Soil erosion and conservation • Biodiversity • Tanzania's vegetation and soil types
Skills Development Focus
NECTA emphasizes the development of geographical skills through questions that require:
• Map interpretation: Extracting information from topographic maps, calculating gradients, interpreting relief
• Diagram analysis: Interpreting cross-sections, block diagrams, weather maps, hydrological cycles
• Data interpretation: Analyzing climate data, population statistics, economic indicators
• Process explanation: Describing step-by-step how geographical features form
• Spatial analysis: Understanding patterns, distributions, and spatial relationships
• Fieldwork design: Planning geographical investigations and data collection
• Environmental assessment: Evaluating human impact on physical systems
Tanzania-Specific Geographical Knowledge
Students are expected to demonstrate specific knowledge of Tanzania's physical geography:
Landforms & Geology
• East African Rift Valley • Kilimanjaro and volcanic mountains • Central Plateau • Coastal plains • Lakes Victoria, Tanganyika, Nyasa • Major river systems
Climate & Vegetation
• Equatorial climate (Lake Victoria) • Tropical climate (coastal) • Semi-arid (central) • Mountain climate • Savannah grasslands • Miombo woodlands • Coastal forests • Montane forests
Environmental Issues
• Soil erosion (Kondoa, Shinyanga) • Deforestation • Water scarcity • Climate change impacts • Biodiversity conservation • Sustainable resource management
Note: The NECTA Geography 1 examination emphasizes integrated understanding of physical systems. Students must demonstrate how atmospheric, hydrological, geological, and biological systems interact to create Tanzania's diverse physical environment.
Common Examination Questions & Solutions
Diagram Description:
A cross-section showing:
1. African Plate being pulled apart by tensional forces
2. Convection currents in the mantle causing divergence
3. Rift valley formed by subsidence between parallel faults
4. Volcanoes along the rift margins
5. Graben structure - down-dropped block between normal faults
Process Explanation:
The East African Rift Valley is forming due to divergent plate boundary processes:
1. Tensional forces pull the African Plate apart
2. Crustal thinning and stretching occur
3. Parallel normal faults develop where crust fractures
4. Central block subsides between faults forming a graben
5. Magma rises through fractures creating volcanoes
6. Eventually, if divergence continues, new oceanic crust will form
1. Lake Tanganyika:
• World's second deepest lake (1,470m)
• Formed in deepest part of western rift
• Steep fault scarps along shores
2. Ngorongoro Crater:
• Largest intact volcanic caldera in world
• Formed by volcanic collapse
• UNESCO World Heritage Site
3. Eyasi and Manyara Basins:
• Shallow rift valley lakes
• Seasonal flooding creates wetlands
• Important for wildlife and agriculture
(i) Drainage Patterns:
• Internal drainage: Rift valley lakes (Tanganyika, Malawi, Natron) have no outlet to sea
• River capture: Changed river courses as rift developed
• Waterfalls: Created where rivers cross fault scarps
• Drainage reversal: Some rivers reversed flow direction
(ii) Volcanic Activity:
• Volcanic mountains: Kilimanjaro, Meru formed along rift margins
• Fissure eruptions: Along fracture lines in rift floor
• Ash deposits: Created fertile soils on rift margins
• Geothermal activity: Hot springs along faults
1. Tourism: National parks (Serengeti, Ngorongoro), wildlife, volcanoes
2. Agriculture: Volcanic soils fertile for coffee, wheat, maize
3. Fishing: Lakes Tanganyika, Malawi provide fish protein
4. Transport: Lake Tanganyika water transport to neighboring countries
5. Minerals: Soda ash from Lake Natron, geothermal potential
6. Water resources: Lakes supply water for domestic and industrial use
7. Hydropower: Potential from rivers flowing into rift
(b) Lake Tanganyika (deepest), Ngorongoro Crater (caldera), Manyara Basin (rift lake)
(c)(i) Internal drainage, river capture, waterfalls; (ii) Volcanic mountains (Kilimanjaro), geothermal activity
(d) Tourism, agriculture, fishing, transport, minerals, water resources
ITCZ Mechanism:
1. Seasonal migration: ITCZ moves north (March-September) and south (October-February)
2. Convergence: Trade winds from NE and SE converge at ITCZ
3. Uplift: Warm moist air rises, cools, condenses forming clouds
4. Rainfall: Heavy convectional rainfall along ITCZ
Tanzania's Rainfall Pattern:
• Bimodal rainfall: Northern Tanzania experiences long rains (Mar-May) and short rains (Oct-Dec) as ITCZ passes twice
• Unimodal rainfall: Southern Tanzania has single rainy season (Nov-Apr) when ITCZ is south
• Rain shadow: Areas leeward of mountains receive less rain
Temperature Effects:
• Lapse rate: Temperature decreases 6.5°C per 1000m altitude
• Examples:
- Dar es Salaam (sea level): Average 26°C
- Dodoma (1,100m): Average 22°C
- Kilimanjaro summit (5,895m): Average -7°C
Rainfall Effects:
• Orographic rainfall: Windward slopes receive more rain
• Examples:
- Usambara Mountains windward: 2000mm/year
- Usambara Mountains leeward: 800mm/year
- Mount Meru slopes: 2500mm/year at 2000m
Specific Regions:
1. Southern Highlands: Cool temperatures allow temperate crops (wheat, pyrethrum)
2. Kilimanjaro slopes: Altitudinal zones from tropical to alpine
3. Plateau areas: Lower temperatures than coastal areas at same latitude
(i) Lake Victoria Basin:
• Rainfall pattern: Bimodal with peaks in April and November
• Total rainfall: 1200-2000mm annually
• Causes:
- Lake effect enhances convection
- ITCZ passes twice annually
- Local thunderstorms common
• Dry seasons: June-August (long dry), January-February (short dry)
(ii) Central Plateau (Dodoma Region):
• Rainfall pattern: Unimodal (Dec-Apr)
• Total rainfall: 500-800mm annually
• Causes:
- Rain shadow effect from surrounding highlands
- Distance from moisture sources
- Continental location
• Dry season: May-November (7 months)
• Rainfall reliability: Low, erratic, drought-prone
1. Changing Rainfall Patterns:
• Increased rainfall variability and uncertainty
• More intense rainfall events causing soil erosion
• Longer dry spells affecting crop growth
• Shifting planting seasons
2. Temperature Increases:
• Heat stress on crops and livestock
• Increased evaporation reducing soil moisture
• Altitudinal shift of suitable growing zones
• Reduced yields of temperature-sensitive crops (coffee, tea)
3. Extreme Weather Events:
• More frequent droughts affecting rain-fed agriculture
• Floods damaging crops and infrastructure
• Pest and disease outbreaks in warmer conditions
• Reduced pasture productivity for livestock
Specific Examples in Tanzania:
• Coffee production declining in lower altitude areas
• Maize yields reduced by 10-20% in some regions
• Livestock mortality during droughts in central Tanzania
(b) Temperature decreases 6.5°C/1000m, windward slopes get more rain
(c)(i) Lake Victoria: bimodal, 1200-2000mm; (ii) Central plateau: unimodal, 500-800mm, drought-prone
(d) Changing rainfall patterns, temperature increases, extreme weather events affecting crops
Diagram Description:
A circular diagram showing:
1. Evaporation: From Indian Ocean, lakes, rivers, soil
2. Transpiration: From vegetation in basin
3. Condensation: Cloud formation over mountains
4. Precipitation: Rainfall in catchment areas
5. Infiltration: Water soaking into soil
6. Surface runoff: Overland flow to rivers
7. Groundwater flow: Through aquifers to rivers
8. River discharge: Flow to Indian Ocean
Rufiji Basin Specifics:
• Catchment area: 177,000 km² (20% of Tanzania)
• Major tributaries: Great Ruaha, Kilombero, Luwegu
• Rainfall input: 800-2000mm annually in different parts
• Evapotranspiration: High due to tropical temperatures
• Seasonal variation: High flow in rainy season (Mar-May), low in dry season
1. Hydraulic Action:
• Force of water against river banks and bed
• Compresses air in cracks, causing pressure buildup
• Common in steep upper course with high velocity
2. Abrasion/Corrasion:
• Rocks and sediment carried by river scrape against bed
• Creates potholes in bedrock
• Most effective where bedload is coarse
3. Attrition:
• Rocks in load collide and break into smaller pieces
• Creates rounded sediment particles
• Increases downstream
4. Solution/Corrosion:
• Chemical dissolution of soluble rocks (limestone)
• Important in areas with carbonate rocks
Upper Course (Highlands):
• Gradient: Steep (1:10 to 1:100)
• Velocity: High due to steep gradient
• Channel: Narrow, V-shaped valley
• Processes: Vertical erosion dominant
• Load: Large, angular bedload
• Landforms: Waterfalls, gorges, interlocking spurs
Middle Course (Plateau):
• Gradient: Moderate (1:100 to 1:500)
• Velocity: Moderate
• Channel: Wider, beginning of meanders
• Processes: Lateral erosion increases
• Load: Smaller, rounded sediment
• Landforms: River cliffs, slip-off slopes, floodplains begin
Lower Course (Coastal Plain):
• Gradient: Gentle (less than 1:500)
• Velocity: Slow
• Channel: Very wide, extensive meanders
• Processes: Deposition dominant
• Load: Fine silt and clay in suspension
• Landforms: Oxbow lakes, levees, delta, floodplains
Negative Impacts:
1. Habitat destruction:
• Flooding of 1,200 km² of terrestrial habitat
• Loss of riparian forests and wildlife corridors
• Displacement of species including endangered
2. River ecosystem disruption:
• Changed flow regime affecting downstream ecosystems
• Reduced sediment transport affecting delta formation
• Barrier to fish migration (especially catfish)
3. Water quality changes:
• Stagnant water may increase water-borne diseases
• Reduced oxygen in deep water affecting aquatic life
• Accumulation of pollutants in reservoir
4. Social impacts:
• Displacement of local communities
• Loss of agricultural land and livelihoods
• Changes in downstream water availability
Positive Aspects/Mitigation:
• Renewable energy: Reduces fossil fuel dependence
• Flood control: Regulates downstream flooding
• Fisheries: Potential for reservoir fisheries
• Irrigation: Potential for downstream irrigation
(b) Erosional processes: hydraulic action, abrasion, attrition, solution
(c) Upper: steep, erosion; Middle: moderate, both; Lower: gentle, deposition
(d) Impacts: habitat loss, ecosystem disruption, water quality, social displacement; Benefits: renewable energy
Mechanical/Physical Weathering:
• Breaks rock into smaller pieces without chemical change
• Examples:
1. Freeze-thaw weathering: Water expands 9% when freezing, exerting pressure in cracks
2. Exfoliation: Outer layers peel off due to pressure release or thermal expansion
Chemical Weathering:
• Alters rock composition through chemical reactions
• Examples:
1. Carbonation: CO₂ + H₂O → carbonic acid reacts with limestone
2. Hydrolysis: Water reacts with minerals like feldspar to form clay
Comparison:
• Mechanical: Faster in arid/cold climates
• Chemical: Faster in hot/wet climates (like Tanzania)
(i) Climate:
• Temperature: Higher temps increase chemical weathering rates
• Rainfall: More rain increases leaching (nutrients washed down)
• Tanzanian examples:
- Coastal areas: High temp + rain = deep, leached soils
- Central plateau: Low rain = shallow, less developed soils
(ii) Parent Material:
• Determines mineral composition and texture
• Tanzanian examples:
- Volcanic areas (Kilimanjaro): Rich in nutrients, dark color
- Sandstone areas: Sandy, low nutrient retention
- Alluvial plains (Rufiji): Fertile, layered soils
(iii) Vegetation:
• Adds organic matter (humus)
• Roots help break up parent material
• Tanzanian examples:
- Forest areas: Thick organic layer (O horizon)
- Grasslands: Less organic matter but deep root systems
- Cultivated areas: Reduced organic matter over time
Typical Soil Profile (Horizons):
O Horizon: Organic layer (leaf litter)
A Horizon: Topsoil - dark, rich in organic matter
E Horizon: Eluviation layer - leached of minerals (not always present)
B Horizon: Subsoil - accumulation of leached materials
C Horizon: Weathered parent material
R Horizon: Bedrock
Tanzanian Soil Examples:
1. Volcanic Soils (Andisols - Kilimanjaro):
• Deep, dark, high organic matter
• Good water retention
• Excellent for coffee, bananas
2. Laterite Soils (Oxisols - Coastal):
• Red color from iron oxides
• Acidic, low fertility
• Hard pan formation when exposed
3. Alluvial Soils (Floodplains):
• Layered deposition
• High fertility
• Good for rice cultivation
Causes of Erosion in Kondoa:
1. Deforestation: Clearing for agriculture and fuelwood
2. Overgrazing: Too many livestock compacting soil
3. Poor farming practices: Plowing up/down slope, no contour farming
4. Geological factors: Soft sedimentary rocks easily eroded
5. Climate: Intense seasonal rainfall on bare soil
Consequences:
1. Soil loss: Up to 200 tons/ha/year lost
2. Reduced fertility: Loss of topsoil and nutrients
3. Sedimentation: Siltation of rivers and reservoirs
4. Poverty cycle: Lower yields → more land clearing
5. Gully formation: Deep channels making land unusable
Sustainable Management Strategies:
1. Afforestation: Planting trees on slopes
2. Contour farming: Plowing along contours
3. Terracing: Creating level platforms on slopes
4. Agroforestry: Integrating trees with crops
5. Gully rehabilitation: Check dams, vegetation planting
6. Community education: Sustainable land use practices
7. Alternative livelihoods: Reducing pressure on land
(b)(i) Climate: temp/rain affect weathering; (ii) Parent material: determines nutrients; (iii) Vegetation: adds organic matter
(c) Profile: O, A, B, C, R horizons; Examples: volcanic (fertile), laterite (acidic), alluvial (layered)
(d) Causes: deforestation, overgrazing; Consequences: soil loss, poverty; Solutions: afforestation, terracing, education
1cm = 50,000cm = 500m = 0.5km
Distance on map: 8cm
Actual ground distance = 8 × 0.5km = 4km
Alternatively:
8cm × 50,000 = 400,000cm = 4,000m = 4km
A = 1250m, B = 1180m
Difference = 1250 - 1180 = 70m
Horizontal equivalent (ground distance): 4000m
Gradient as ratio:
Gradient = Vertical interval : Horizontal equivalent
= 70 : 4000
Simplify: Divide both by 70
= 1 : 57.14 (approximately 1:57)
Gradient as percentage:
Percentage = (Vertical interval / Horizontal equivalent) × 100
= (70 / 4000) × 100 = 1.75%
Based on Contour Patterns:
1. Steep Slopes:
• Where contours are closely spaced
• Indicates rapid elevation change
• Possibly hills or escarpments
2. Gentle Slopes/Plateau:
• Where contours are widely spaced
• Indicates flat or gently sloping land
• Suitable for settlement and agriculture
3. Valley/River Course:
• Contours form V-shape pointing upstream
• River flows from high to low contour values
• Valley bottom has highest contour density
4. Hill/Summit:
• Closed contours with increasing values
• Highest point at center of closed contours
• Spot height C (1320m) likely a summit
(i) Settlement Patterns:
• Gentle slopes: Dense settlement due to ease of construction
• Valley bottoms: Linear settlement along rivers for water access
• Steep slopes: Sparse or no settlement due to construction difficulties
• Higher elevations: May have health advantages (fewer mosquitoes)
• Aspect: South-facing slopes preferred in temperate zones (not as relevant in Tanzania)
(ii) Agricultural Activities:
• Gentle slopes: Intensive cultivation, mechanization possible
• Valley bottoms: Irrigated agriculture, rice paddies
• Steep slopes: Terracing, grazing, forestry
• Aspect: North-facing slopes may be drier, affecting crop choice
• Altitude: Determines crop types (coffee at mid-elevations, wheat higher up)
Title: Investigation of river characteristics between points X and Y
Aim: To study how river channel characteristics change downstream
Hypotheses:
1. River width increases downstream
2. River velocity decreases downstream
3. Bedload size decreases downstream
Methodology:
1. Site selection: Choose 3-5 sites at regular intervals between X and Y
2. Data collection:
• Width: Measure with measuring tape at each site
• Depth: Use meter rule at regular intervals across channel
• Velocity: Float method (time object over 10m distance)
• Bedload: Collect and measure 10 random stones at each site
• Slope: Use clinometer to measure valley side slopes
Equipment:
• Measuring tape • Meter rule • Stopwatch • Clinometer • Camera • Notebook
Risk Assessment:
• Check weather forecast • Wear appropriate footwear • Work in groups • Avoid fast-flowing sections
Data Presentation:
• Line graphs for downstream changes • Cross-sectional diagrams • Photographs • Maps showing sites
(b) Gradient = 1:57 or 1.75%
(c) Relief: steep slopes, gentle plateau, river valley, hill summit
(d)(i) Settlement on gentle slopes, valleys; (ii) Agriculture: intensive on gentle slopes, terracing on steep
(e) Fieldwork: study river width, depth, velocity, bedload changes downstream
Additional NECTA Geography 1 Questions
Formation Conditions:
1. Warm water: 23-25°C minimum
2. Clear water: Low sediment for photosynthesis
3. Shallow water: Less than 60m depth for sunlight
4. Salinity: Normal seawater salinity (32-35‰)
5. Wave action: Moderate for oxygenation and food supply
Formation Process:
• Coral polyps secrete calcium carbonate skeletons
• Colonies grow upward and outward over centuries
• Three main types: fringing, barrier, atoll
Tanzanian Distribution:
• Main areas: Mafia Island, Zanzibar, Pemba, Tanga coast
• Types: Mostly fringing reefs close to shore
• Factors: Suitable conditions exist along most of coast except near river mouths (sediment)
1. Hydraulic Action:
• Force of waves compresses air in cracks
• Pressure causes rock to fracture
• Important in storm conditions
2. Abrasion/Corrasion:
• Waves throw sand and pebbles against cliffs
• Acts like sandpaper wearing away rock
• Creates wave-cut notches and platforms
3. Attrition:
• Rocks in water collide and break into smaller pieces
• Creates rounded beach material
• Reduces particle size over time
4. Solution/Corrosion:
• Seawater dissolves soluble rocks (limestone)
• Important in coral reef and limestone areas
Mangrove Forests:
• Location: Intertidal zones, river estuaries
• Conditions: Muddy sediments, brackish water
• Adaptations: Aerial roots, salt excretion
• Functions: Coastal protection, fish nursery, carbon sink
• Tanzanian examples: Rufiji Delta, Tanga, Bagamoyo
Coral Reefs:
• Location: Clear, warm, shallow waters
• Conditions: Hard substrates, full salinity
• Adaptations: Symbiosis with algae, calcium carbonate skeletons
• Functions: Biodiversity hotspots, coastal protection, tourism
• Tanzanian examples: Zanzibar, Mafia Island reefs
Similarities:
• Both provide coastal protection • High biodiversity • Important for fisheries • Threatened by human activities
Hard Engineering:
• Sea walls: Expensive but effective, used in Dar es Salaam
• Groynes: Trap sediment but cause downdrift erosion
• Gabions: Wire cages with rocks, cheaper but less durable
• Effectiveness: Immediate but costly, can worsen problems elsewhere
Soft Engineering:
• Beach nourishment: Adding sand, natural but temporary
• Dune regeneration: Planting vegetation to stabilize dunes
• Effectiveness: More sustainable but requires maintenance
Managed Retreat:
• Allowing erosion in some areas, relocating infrastructure
• Effectiveness: Cost-effective long-term but socially difficult
Ecosystem-Based Approaches:
• Mangrove restoration: Highly effective, multiple benefits
• Coral reef protection: Marine protected areas (Mnazi Bay)
• Effectiveness: Most sustainable, enhances biodiversity
Tanzanian Context:
• Combination needed • Community involvement crucial • Consider local livelihoods • Integrated Coastal Zone Management (ICZM) approach
(b) Erosional processes: hydraulic action, abrasion, attrition, solution
(c) Mangroves: muddy estuaries; Coral reefs: clear waters; Both: coastal protection, biodiversity
(d) Management: hard engineering (effective but costly), soft engineering, managed retreat, ecosystem-based (most sustainable)
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