Environmental Impact Assessment
Senior 6 · Entrepreneurship
Environmental Impact Assessment
Lesson 1 of 4
25 min
Picture a tea factory in the hills of the Western Province. Its green leaf comes from bushes that need regular rain, fertile soil and a cool highland climate. The factory uses clean water to wash its machines, heat to dry the leaf and workers from the surrounding villages. At the same time it sends out smoke from its driers, wastewater from its washing and lorries full of tea along narrow roads. (An illustrative factory, not a real one.)
The factory cannot survive without its environment, and its environment will not stay healthy if the factory ignores it. This unit is about managing that two-way relationship: first by understanding it, then by using a legal tool, the environmental impact assessment, to plan a project so that the damage is avoided before it happens.
Definition
Environment: everything around us that affects life and human activity, both natural (air, water, soil, climate, plants and animals, landscapes) and built (buildings, roads and other man-made surroundings), together with social, economic and cultural factors. Rwanda's Law N° 48 of 2018 on environment defines it in this broad way (Article 2).
Example: for a hotel beside Lake Kivu, the environment includes the lake water, the fish in it, the beach, the road to the hotel, and the fishing families who live nearby.
| Part | What it includes | Example |
|---|---|---|
| Physical (non-living) | Air, water, soil, rocks and minerals, climate, landscape | The Nyabarongo river; the clay soils of a valley |
| Biological (living) | Plants, animals, micro-organisms, and the ecosystems they form | A wetland with papyrus, fish and birds |
| Built (man-made) | Buildings, roads, bridges, water and power networks | A market, a feeder road, a water pipeline |
| Social and economic | People's health, jobs, homes, culture and ways of earning a living | Farmers who irrigate from a stream; a heritage site |
Definition
Ecosystem services: the benefits people and businesses receive free from nature, such as clean water, fertile soil, pollination, flood control and a stable climate.
Example: a wetland upstream of a town slows floodwater and traps mud, so a water company downstream spends less on cleaning water.
| Part affected | How businesses affect it | Typical sources |
|---|---|---|
| Air | Smoke, dust, fumes and greenhouse gases; bad smells | Kilns and driers burning wood, quarries, vehicles, generators |
| Water | Untreated wastewater, oils and chemicals; soil washed into rivers; over-use of water | Food and coffee processing, garages, mines, car washes, construction sites |
| Land and soil | Clearing, digging and paving; erosion; dumping of solid and plastic waste | Quarries, brickworks, building sites, markets |
| Plants and animals | Cutting forests, draining wetlands, disturbing wildlife; or planting and restoring | Farms, sawmills, construction, tourism |
| People | Noise, accidents, health risks, loss of land or homes; but also jobs, income and services | Factories, roads, mines, markets, hotels |
Impacts can be positive (jobs, better roads, planted trees) as well as negative, direct (smoke from a chimney) or indirect (more lorries on a road because a factory opened), short-term (dust during building) or long-term (a drained wetland that never recovers).
Definition
Environmental impact: any change to the environment, harmful or beneficial, that results wholly or partly from a project or business activity.
Example: a new maize mill brings jobs (positive, social) but its dust settles on nearby homes (negative, air).
Tip
Think "takes and returns". For any business, ask what it TAKES from the environment (water, land, energy, materials, labour) and what it RETURNS (waste, emissions, noise, and also wages and products). Every impact you will ever be asked to identify sits in one of those two lists.
Worked example 1: impacts of a brickworks
A cooperative plans to make fired clay bricks beside a valley, using clay dug on site and kilns fired with wood. (Illustrative.) Identify its likely impacts on each part of the environment.
| Part | Likely impact | Positive or negative |
|---|---|---|
| Air | Smoke and carbon dioxide from the kilns | Negative |
| Land and soil | Clay pits left open; soil loosened and eroded | Negative |
| Water | Pits fill with standing water where mosquitoes can breed; mud washed into the stream | Negative |
| Plants and animals | Trees cut for fuelwood | Negative |
| People | Jobs for members; affordable bricks for local housing | Positive |
Conclusion: the business is useful but has several negative impacts. Each one suggests a remedy: refill and replant the pits, buy fuel from a managed woodlot or use more efficient kilns, and keep a buffer strip beside the stream. Planning these remedies in advance is exactly what an EIA does.
Worked example 2: sizing a wastewater pond
A small fruit-juice factory will produce about of wastewater a day. Its engineer wants a settling pond that holds 5 days of wastewater, so that solids settle before the water is treated further. (Illustrative figures.)
Step 1: volume needed.
Step 2: depth of a pond 10 m long and 4 m wide.
Interpret: the pond needs land, costs money and must be fenced for safety. A business that learns this at the planning stage can budget for it; one that learns it after the river is polluted pays far more, in fines, clean-up and lost trust.
Warning
Do not list only the bad news. Examiners expect both positive and negative impacts, and both environmental and social ones. A good answer to "state the impacts of a mining project" mentions jobs, tax revenue and roads as well as dust, polluted water and damaged land.
Eurac Research, "What are ecosystem services?" (about 3 minutes, animated). Watch for the services a landscape provides free: food, clean water, protection from floods and landslides, and recreation. Think about which Rwandan businesses depend on each one.
Practice
Sources and credits
Written by Ganzaa: the tea factory case, the diagram, the tables, the worked examples and the practice items. The businesses and figures are illustrative (2026).
