Review: protecting water, soil and habitats
A habitat must give food, water and shelter. It can be destroyed by natural events, such as fires and volcanoes, and by people through clearing land, pollution and invasive species. The water hyacinth in the Nile is one invader. It is better to prevent water pollution than to clean it up, by treating sewage, using fertilizer carefully, keeping plants by rivers and binning rubbish. Only about three out of every hundred parts of Earth’s water is fresh, so irrigation should waste less: drip systems, moisture sensors and watering in cool hours help. Engineers follow the steps ask, imagine, plan, build, test and improve. A green city keeps parks and wetlands, uses clean energy and public transport, and protects soil. Each plan should name a problem and give a fix.
| Problem | Fix |
|---|---|
| water pollution | treat sewage, use fertilizer carefully, bin rubbish |
| water waste | drip irrigation, moisture sensors, water in cool hours |
| habitat loss | protect wetlands and parks |
| soil loss | plants, trees, trenches |
| Water | ml |
|---|---|
| poured | 400 |
| in the pot | 250 |
| runoff | 100 |
| spilled | ? |
Planner’s challenge. With a grown-up, choose a place such as your school. Write three problems for water, soil or habitats there and one fix for each. Then say which design step you would use first to test a fix, and why.