Methods to Reduce Urban Runoff
Introduced| English |
|---|
| Urban runoff/ˈɜːbən ˈrʌnɒf/ |
| Permeable pavement/ˈpɜːməbl ˈpeɪvmənt/ |
| rain garden/reɪn ˈɡɑːdn/ |
| green roof/ɡriːn ruːf/ |
Taming city rain
- In a paved city, rain has nowhere to soak in.
- It rushes off roofs and roads, flooding streets and rivers.
- But clever design can slow the water down and let it soak in.
- These green solutions reduce urban runoff.
The runoff problem
- Urban runoff 城市径流 is rainwater that rushes off hard city surfaces.
- With nowhere to soak in, it overwhelms drains and floods streets.
- On the way, it picks up oil, litter, and chemicals.
- All that pollution pours untreated into rivers and lakes.
Why is urban runoff a problem?
Fast runoff from paved cities floods streets and washes oil, litter, and chemicals into waterways.
Let the water soak in
- Permeable pavement 透水路面 has gaps that let rain soak through into the soil.
- A rain garden 雨水花园 is a planted dip that collects and absorbs runoff.
- Both slow the water and let the ground filter it.
- Instead of flooding, the rain recharges the groundwater.
Permeable pavement helps because it…
Permeable pavement has gaps that let rainwater soak into the soil instead of running off.
A planted, low area designed to soak up stormwater is called a rain ____.
A rain garden collects runoff and lets plants and soil absorb it, reducing flooding and pollution.
Greening the city
- A green roof 绿色屋顶 is a rooftop planted with vegetation.
- Its plants soak up rainwater and shade the building.
- This cuts runoff and also eases the urban heat island.
- Trees and green spaces do the same across a whole city.
Helps or worsens runoff?
Sort each urban feature by whether it reduces or increases stormwater runoff.
Green roofs, planted with vegetation, help absorb rainwater and cool buildings.
A green roof's plants soak up rain and shade the building, reducing both runoff and heat.
Select all methods that reduce urban runoff.
Solid concrete increases runoff. The other three all reduce it.
These methods work by copying nature's way of handling rain: letting it soak into soil and plants instead of shedding it off hard surfaces. The more a city acts like a forest — with permeable ground and greenery — the less it floods. Fighting runoff means bringing nature back into the city.
A car park that drinks the rain:
- A normal concrete car park sends every drop of rain rushing into the drains.
- Rebuilt with permeable pavement, the same car park lets the rain soak straight through.
- The water refills the groundwater instead of flooding the street — the same land, a very different outcome.
Urban runoff floods streets and pollutes rivers because paved cities shed rain fast. Solutions let water soak in instead: permeable pavement, rain gardens, and green roofs all absorb rainwater, reduce flooding and pollution, and recharge groundwater — by making the city behave more like nature.