Freshwater: The River Nene - flood mitigation Flashcards
Where did the river used to frequently flood?
Northampton
What happened on 9th April 1998?
heavy rain caused River Nene and Grand Union Canal to overflow.
What were the impacts of the flood in 1998?
flooded parts of the town and 2 people died
What did the Environment Agency do by 2002?
They had completed a 6.8 million pound project to protect areas of Northampton hardest hit by past flooding.
Which years were further defence works carried out in the town?
2003 and 2007
What are the hard engineering defences?
- Clay flood embankment
- Earth embankments
- Flood walls
- Gabions
What are the soft engineering defences?
- Washland
- Warning system
When was the clay flood embankment built?
2002
How long is the clay flood embankment?
450 m long
Where is the clay food embankment located?
Weedon
How much has the clay flood embankment raised the level of land?
6.8 m
What is behind the clay flood embankment and what is its purpose?
flood storage area prevents further flooding downstream and developed as a habitat for flora and fauna
Where is the earth embankment built?
Upton
How many metres from the river is the earth embankment built?
10m
Why was the Earth embankment built?
to increase channel capacity
benefits of building the earth embankment?
- been visually improved by planting trees
- has footpaths
Where was the flood wall built?
Foot Meadow
How high is the flood wall and why?
4m high to protect housing and industry, created an open area of land for river to flood into, protecting the railway station.
Where are the gabions built?
Foot Meadow
What are the purpose of the gabions?
to protect river banks from erosion giving added security to the new housing beside the river.
Where is the washland built?
around Upton, near Sixfields
When was the washland created?
2007
How much does the washland cost?
around 8 million pounds
Why was the washland created?
so that water can be diverted from the river in a controlled manner in order to reduce the risk of flooding downstream.
Allows 1.2 million cubic metre flood water storage.
