4.7 River landscapes and human activity Flashcards
How can urbanisation affect flood hydrographs?
Water cannot infiltrate into impermeable surfaces so more surface run off. Gutters and drains take runoff to rivers but increases the discharge.
How can deforestation affect flood hydrographs?
Trees take up water from the ground and reduces runoff but cutting them down increases runoff and creates more water to enter the river channel which increase the discharge.
How do physical factors cause flooding in the river eden?
Cumbria faces the prevailing south-westerly winds so the climate is mild and wet.
It is one of the wettest parts of the UK and can have intense rainfall.
The river eden is bordered by the lake district and the North Pennines and are made of impermeable rock so water cant soak into the ground which increases runoff.
Snowfall is common during winter so adds water to the river channel quickly.
How do human factors cause flooding in the river eden?
Carlisle is a large built up area and has huge development on the floodplain. This affects the floodplains ability to absorb floodwater. There is little vegetation leading to little infiltration meaning higher surface run off.
Natural woodlands and heathlands have been cleared from the uplands and this increases surface run off when it rains.
Parts of the Eden valley has been drained to be more suitable for farming. This increases the water flow to the river channel.
Effects of flooding for people
People can be killed or injured by the flood.
Roads bridges and rail lines can be damaged or destroyed.
Lack of clean water due to sewage contamination.
Possessions in your home can be damaged or even washed away.
People can be made homeless as their properties are damaged.
There is a loss of livelihoods due to businesses being shut down and disrupting power supplies.
Effects of flooding on the environment.
Flood water is contaminated with sewage and pollutes rivers.
Farmland is ruined by salt and sediment deposited after the flood.
River banks are eroded and this erodes the river landscape.
The floodwater can uproot trees and plants and could kill plants after the flood.
