Source: https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-16-flood-risk-factors

[Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [IGCSE](https://senecalearning.com/en-gb/revision-notes/igcse.md) › [Geography](https://senecalearning.com/en-gb/revision-notes/igcse/geography.md) › [Edexcel IGCSE](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse.md) › Flood Risk Factors

# Flood Risk Factors

Geography: Edexcel IGCSE, topic 1.1.16

## Factors Affecting Flood Risk

When the amount of water in a river is greater than the river's capacity, flooding will happen. Increasing river level is caused by increasing river discharge. There are human and physical factors that can increase discharge, and therefore cause flooding:

### Precipitation

![Precipitation](https://image-v2.cdn.app.senecalearning.com/2018-04/099bab40-ed70-4a52-814e-a547b55afd04/shutterstock_148484927%20(1).jpg)

- Heavy rainfall causes high runoff because the water arrives so quickly that there isn't enough time for it to infiltrate the soil.
- Prolonged rainfall makes the soil become saturated, and so any more rainfall will run off instead of infiltrating.

### Geology

![Geology](https://image-v2.cdn.app.senecalearning.com/2018-04/097fabb4-6ff4-4cd7-878c-83913859fac0/shutterstock_1028616160.jpg)

- Runoff is higher in areas that are mainly made up of impermeable soil (e.g. clay) or impermeable rock (e.g. granite).

### Relief

![Relief](https://image-v2.cdn.app.senecalearning.com/2018-04/4fef5ef4-78e4-4752-b2e5-ce5aa0933092/shutterstock_749460433.jpg)

- Rainfall will reach the river channel quicker in a steep-sided valley.

### Land use

![Land use](https://image-v2.cdn.app.senecalearning.com/2018-04/19902426-495b-49f8-b530-e02cc346740c/shutterstock_360143117.jpg)

- Buildings and roads are usually made of impermeable materials. More impermeable surfaces mean more runoff and more discharge.
- Trees intercept water and store water that they take up from the ground. Removing trees will, therefore, increase flooding risk as more water will be finding its way into the river channel.

## Test yourself on Flood Risk Factors

- Runoff is high in areas dominated by impermeable surfaces. Which of the following have impermeable surfaces?
- Which of the following would increase the risk of flooding?

[Practise this topic for free](https://app.senecalearning.com/classroom/course/ef6d2f62-5eb8-4168-aaaf-48efdb77968e/section/b1482639-25b2-40f8-a890-a424c0bdfc04/session)

- Previous topic: [1.1.15 Vertical & Lateral Erosion](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-15-vertical-and-lateral-erosion.md)
- Next topic: [1.1.17 Human Activities on Rivers](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-17-human-activities-on-rivers.md)

## Geography: Edexcel IGCSE contents

### 1 Physical Geography
- 1.1 River Environments
  - [1.1.1 Weathering](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-1-weathering.md)
  - [1.1.2 Mass Movement](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-2-mass-movement.md)
  - [1.1.3 Erosion](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-3-erosion.md)
  - [1.1.4 Transportation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-4-transportation.md)
  - [1.1.5 Deposition](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-5-deposition.md)
  - [1.1.6 River Landforms: Waterfalls & Gorges](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-6-river-landforms-waterfalls-and-gorges.md)
  - [1.1.7 River Landforms: Interlocking Spurs](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-7-river-landforms-interlocking-spurs.md)
  - [1.1.8 River Landforms: Flood Plains](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-8-river-landforms-flood-plains.md)
  - [1.1.9 River Landforms: Point Bars](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-9-river-landforms-point-bars.md)
  - [1.1.10 River Landforms: Levees](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-10-river-landforms-levees.md)
  - [1.1.11 River Landforms: Meanders](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-11-river-landforms-meanders.md)
  - [1.1.12 River Landforms: Oxbow Lakes](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-12-river-landforms-oxbow-lakes.md)
  - [1.1.13 River Landscape Changes: Long Profile](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-13-river-landscape-changes-long-profile.md)
  - [1.1.14 River Landscape Changes: Cross Profile](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-14-river-landscape-changes-cross-profile.md)
  - [1.1.15 Vertical & Lateral Erosion](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-15-vertical-and-lateral-erosion.md)
  - [1.1.16 Flood Risk Factors](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-16-flood-risk-factors.md)
  - [1.1.17 Human Activities on Rivers](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-17-human-activities-on-rivers.md)
  - [1.1.18 River Management: Hard Engineering](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-18-river-management-hard-engineering.md)
  - [1.1.19 River Management: Soft Engineering](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-19-river-management-soft-engineering.md)
  - [1.1.20 Case Study: The River Eden - Landforms](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-20-case-study-the-river-eden-landforms.md)
  - [1.1.21 Case Study: The River Eden - Climate](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-21-case-study-the-river-eden-climate.md)
  - [1.1.22 Case Study: The River Eden - Geology](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-22-case-study-the-river-eden-geology.md)
  - [1.1.23 Case Study: The River Eden - Management](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-23-case-study-the-river-eden-management.md)
  - [1.1.24 Case Study: The River Eden - Human Activity](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-24-case-study-the-river-eden-human-activity.md)
  - [1.1.25 End of Topic Test - River Environments](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-1-25-end-of-topic-test-river-environments.md)
- 1.2 Coastal Environments
  - [1.2.1 Weathering](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-1-weathering.md)
  - [1.2.2 Mass Movement](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-2-mass-movement.md)
  - [1.2.3 Erosion](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-3-erosion.md)
  - [1.2.4 Deposition](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-4-deposition.md)
  - [1.2.5 Longshore Drift](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-5-longshore-drift.md)
  - [1.2.6 Sediment Transportation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-6-sediment-transportation.md)
  - [1.2.7 Wave Action on Coasts](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-7-wave-action-on-coasts.md)
  - [1.2.8 Other Factors Influencing Coasts](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-8-other-factors-influencing-coasts.md)
  - [1.2.9 Coastal Landforms: Wave-cut Platforms & Cliffs](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-9-coastal-landforms-wave-cut-platforms-and-cliffs.md)
  - [1.2.10 Coastal Landforms: Headlands & Bays](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-10-coastal-landforms-headlands-and-bays.md)
  - [1.2.11 Coastal Landforms: Caves, Arches & Stacks](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-11-coastal-landforms-caves-arches-and-stacks.md)
  - [1.2.12 Coastal Deposition](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-12-coastal-deposition.md)
  - [1.2.13 Spits, Bars & Sand Dunes](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-13-spits-bars-and-sand-dunes.md)
  - [1.2.14 Human Activity on Coasts](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-14-human-activity-on-coasts.md)
  - [1.2.15 Coastal Defences: Hard Engineering](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-15-coastal-defences-hard-engineering.md)
  - [1.2.16 Coastal Defences: Soft Engineering](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-16-coastal-defences-soft-engineering.md)
  - [1.2.17 Coastal Defences: Managed Retreat](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-17-coastal-defences-managed-retreat.md)
  - [1.2.18 Case Study: Holderness Coast Overview](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-18-case-study-holderness-coast-overview.md)
  - [1.2.19 Case Study: Holderness Coast Management](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-19-case-study-holderness-coast-management.md)
  - [1.2.20 Case Study: Holderness Coast Defences](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-20-case-study-holderness-coast-defences.md)
  - [1.2.21 End of Topic Test - Coastal Environments](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-2-21-end-of-topic-test-coastal-environments.md)
- 1.3 Hazardous Environments - Tropical Cyclones
  - [1.3.1 Characteristics of a Tropical Cyclone](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-1-characteristics-of-a-tropical-cyclone.md)
  - [1.3.2 Structure of a Tropical Cyclone](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-2-structure-of-a-tropical-cyclone.md)
  - [1.3.3 Physical Hazards of Tropical Cyclones](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-3-physical-hazards-of-tropical-cyclones.md)
  - [1.3.4 The Impacts of Tropical Cyclones](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-4-the-impacts-of-tropical-cyclones.md)
  - [1.3.5 Responses to Tropical Cyclones](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-5-responses-to-tropical-cyclones.md)
  - [1.3.6 Vulnerability to Tropical Cyclones](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-6-vulnerability-to-tropical-cyclones.md)
  - [1.3.7 Preparing for Tropical Cyclones](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-7-preparing-for-tropical-cyclones.md)
  - [1.3.8 Case Study: Katrina](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-8-case-study-katrina.md)
  - [1.3.9 Case Study: Nargis](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-3-9-case-study-nargis.md)
- 1.4 Hazardous Environments - Earthquakes & Volcanoes
  - [1.4.1 Earthquakes](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-1-earthquakes.md)
  - [1.4.2 Features of an Earthquake](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-2-features-of-an-earthquake.md)
  - [1.4.3 Types of Earthquake](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-3-types-of-earthquake.md)
  - [1.4.4 Case Study: L'Aquila](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-4-case-study-laquila.md)
  - [1.4.5 Case Study: Chile](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-5-case-study-chile.md)
  - [1.4.6 Case Study: Japan & Pakistan - Planning](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-6-case-study-japan-and-pakistan-planning.md)
  - [1.4.7 Volcanoes](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-7-volcanoes.md)
  - [1.4.8 Types of Volcanoes](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-8-types-of-volcanoes.md)
  - [1.4.9 Volcanic Eruptions](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/1-4-9-volcanic-eruptions.md)

### 2 Human Geography
- 2.1 Economic Activity & Energy
  - [2.1.1 Increasing Energy Consumption](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-1-1-increasing-energy-consumption.md)
  - [2.1.2 Non-Renewable Energy - Nuclear](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-1-2-non-renewable-energy-nuclear.md)
  - [2.1.3 Non-Renewable Energy - Fossil Fuels](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-1-3-non-renewable-energy-fossil-fuels.md)
  - [2.1.4 Renewable Energy - Solar](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-1-4-renewable-energy-solar.md)
  - [2.1.5 Renewable Energy - Water & Bio](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-1-5-renewable-energy-water-and-bio.md)
  - [2.1.6 Renewable Energy - Hydro](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-1-6-renewable-energy-hydro.md)
  - [2.1.7 Energy - Statistical Skills](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-1-7-energy-statistical-skills.md)
- 2.2 Rural Environments
  - [2.2.1 Rainforests](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-2-1-rainforests.md)
  - [2.2.2 Temperate Forests](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-2-2-temperate-forests.md)
  - [2.2.3 Characteristics of a Temperate Forest](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-2-3-characteristics-of-a-temperate-forest.md)
  - [2.2.4 Goods & Services in Temperate Forests](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-2-4-goods-and-services-in-temperate-forests.md)
  - [2.2.5 Deserts](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-2-5-deserts.md)
  - [2.2.6 Tundra](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-2-6-tundra.md)
- 2.3 Urban Environments
  - [2.3.1 Urbanisation in Different Countries](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-3-1-urbanisation-in-different-countries.md)
  - [2.3.2 Causes of Urbanisation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-3-2-causes-of-urbanisation.md)
  - [2.3.3 Consequences of Urbanisation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-3-3-consequences-of-urbanisation.md)
  - [2.3.4 Sustainable Urbanisation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-3-4-sustainable-urbanisation.md)
  - [2.3.5 Case Study: Rapid Urbanisation in Mexico City](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-3-5-case-study-rapid-urbanisation-in-mexico-city.md)
  - [2.3.6 End of Topic Test - Urbanisation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/2-3-6-end-of-topic-test-urbanisation.md)

### 3 Global Issues
- 3.1 Fragile Environments & Climate Change
  - [3.1.1 Natural Causes of Climate Change](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-1-1-natural-causes-of-climate-change.md)
  - [3.1.2 Effects of Climate Change on the Environment](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-1-2-effects-of-climate-change-on-the-environment.md)
  - [3.1.3 Effects of Climate Change on People](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-1-3-effects-of-climate-change-on-people.md)
  - [3.1.4 Impacts of Deforestation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-1-4-impacts-of-deforestation.md)
  - [3.1.5 End of Topic Test - Climate Change](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-1-5-end-of-topic-test-climate-change.md)
  - [3.1.6 Increasing Water Supply](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-1-6-increasing-water-supply.md)
  - [3.1.7 Sustainable Rainforest Management](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-1-7-sustainable-rainforest-management.md)
- 3.2 Globalisation & Migration
  - [3.2.1 Globalisation - Transport](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-1-globalisation-transport.md)
  - [3.2.2 Globalisation - Communication Networks & Banking](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-2-globalisation-communication-networks-and-banking.md)
  - [3.2.3 Push & Pull Factors](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-3-push-and-pull-factors.md)
  - [3.2.4 TNCs & Globalisation](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-4-tncs-and-globalisation.md)
  - [3.2.5 Tourism Landscapes](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-5-tourism-landscapes.md)
  - [3.2.6 The Growth of Tourism](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-6-the-growth-of-tourism.md)
  - [3.2.7 The Economic Benefits of Tourism](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-7-the-economic-benefits-of-tourism.md)
  - [3.2.8 The Social & Cultural Benefits of Tourism](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-8-the-social-and-cultural-benefits-of-tourism.md)
  - [3.2.9 The Economic Costs of Tourism](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-9-the-economic-costs-of-tourism.md)
  - [3.2.10 The Social & Cultural Costs of Tourism](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-10-the-social-and-cultural-costs-of-tourism.md)
  - [3.2.11 Managing Tourism - Sustainability](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-11-managing-tourism-sustainability.md)
  - [3.2.12 Managing Tourism - Quotas & Tourism Hubs](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-2-12-managing-tourism-quotas-and-tourism-hubs.md)
- 3.3 Development & Human Welfare
  - [3.3.1 Ways of Defining Development](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-1-ways-of-defining-development.md)
  - [3.3.2 Different Ways of Measuring Development](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-2-different-ways-of-measuring-development.md)
  - [3.3.3 Environmental Factors Causing Uneven Development](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-3-environmental-factors-causing-uneven-development.md)
  - [3.3.4 Historical Factors Causing Uneven Development](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-4-historical-factors-causing-uneven-development.md)
  - [3.3.5 Economic Factors Causing Uneven Development](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-5-economic-factors-causing-uneven-development.md)
  - [3.3.6 Patterns of Development](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-6-patterns-of-development.md)
  - [3.3.7 How Can we Reduce the Global Development Gap?](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-7-how-can-we-reduce-the-global-development-gap.md)
  - [3.3.8 Top-Down & Bottom-Up Development](https://senecalearning.com/en-gb/revision-notes/igcse/geography/edexcel-igcse/3-3-8-top-down-and-bottom-up-development.md)
