Educational Displays for Schools
5. ...then trying to get rid of all that water!
To move storm water out of the area quickly, some parts of the River Quaggy were straightened and put into concrete channels. These channels look ugly and their high vertical walls make them dangerous. Few animals or plants are able to thrive there.
Notes for teachers
Channelisation of local rivers has been used for many years to move surplus water quickly downstream after heavy rain. But consider the effects of putting a concrete jacket round a river:
- Groundwater cannot get into the river from the bed so flow in summer is reduced to a tiny trickle;
- Deposits of mud on the river bed, home to some invertebrates, are no longer there;
- Areas of pebbles over which water flows rapidly (riffles) and still areas of water dammed behind pebbles (pools) do not exist – both of these are important in-river habitats for invertebrates and fish;
- Fewer pebbles mean much a smaller surface area within the river for algae to grow on;
- No soft bed for rooted water plants, and floating water plants are moved quickly downstream.
- Talk about the effect of channelisation on river habitats and food chains.