Hard engineering = uses expensive heavy machinery to build artificial structures which work against nature to
prevent flooding
● Dams and reservoirs
● Channel straightening
● Embankments
● Flood relief channels
Dams and reservoirs:
→ Dam = large concrete barrier built across river to impede its flow
● Causes valley behind dam to flood and forms an artificial lake /reservoir
● Restricts supply of water downstream
● Water is released in controlled manner through sluice gates in dam
○ Should result in no risk of flooding downstream
Channel straightening:
→ Channel straightening = meandering section of river is engineered to create a widened, straightened, deepened
course
● More efficient course improves navigation → reduces flood risk
Embankments:
→ Embankments = artificially raised river bank
● Raised bank → more water contained in channel and so reduced flood risk
● Embankment is made by moving huge mounds of impermeable soil on river banks to build up their height
● Some are reinforced with gabions/lined with concrete
Flood relief channels:
→ Flood relief channels = artificially made channel , designed as a backup channel for a river that frequently floods
● Works like a bypass
● Engineered channel runs parallel to main river
○ eg/ River Exe has 3 relief channels → cost £8 million following floods in 1960
■ Gate has been built across Exe → automatically closes when there is high discharge and
diverts water into relief channel
⇒ Advantages and disadvantages of hard engineering:
