River Management Strategies Hard And Soft Flashcards
What is hard engineering
Directly intervenes with the rivers natural processes, usually involves building man made structures e.g levees
What is soft engineering
Working with the rivers natural processes. Less building of man made structures and less negative impacts to the environment
What is afforestation
Involves planting trees in the upper basin to increase the lag time as rain is caught as interception
Example for afforestation
The slow flow scheme in Pickering beck where 40,000 trees have been planted since 2009, reducing peak flow by 20%
Why is afforestation sustainable and why (what type of sustainable)
Afforestation blends in with the natural environment and therefore is more environmentally sustainable than hard engineering methods
Full description of afforestation
Four station involves planting trees in the upper basin to increase the LAG TIME as rain is caught by interception one example of this is the SLOW FLOW SCHEME IN PICKERING BECK where 40,000 trees have been planted since 2009 reducing peak flow by 20% forest blends in with environment and is therefore more environmentally sustainable than hard engineering methods
What are washlands and are they sustainable, why?
Wash lands are when areas of land are allowed to flood. This is very environmentally stable as it provides habitats for small animals and plants.
Example for washlands and are they sustainable
One example is the Woodhouse Washland nature reserved in Sheffield as it has seen an increase in wetland wildlife including newts, grass snakes and snipe. This is environmentally sustainable.
Full description for washlands
When areas of land are allowed to flood this is very environmentally stable as it provides habitats for small animals and plants one example is the Woodhouse Washland nature reserve in Sheffield as it has seen an increase in wetland wildlife including newts, grass snakes and snipe. This is very environmentally sustainable.
What is land use zoning
Where building is only allowed on the floodplain in a certain order of value. Low value buildings are close to the river and the higher value ones are further away from the river.
Example for land use zoning and what type of sustainable are they
For example, River Tay in Dundee, land close to the river is used for recreation e.g. football pitches and golf courses and houses and industry are further away from the channel where flooding is less likely to occur. This makes land use zoning environmentally sustainable and economically sustainable.
What is resectioning and the aim
Resectioning involves the channel cross-section being enlarged widen or deepen. The aim of this is to create a more energy efficient river with a broad bed and steep banks, often involves lining the channel with concrete to give a higher channel capacity
Example for resectioning
For example, River Valency, Boscastle England went through a 4.5 million pound flood prevention scheme and the river was lowered by 0.75 m and the river was widened in parts.
What is realignment and example and disadvantage, sustainable?
When meanders are cut through and straightened and filled with dredge spoil the aim is to create a straighter more efficient channel e.g. the river MAIN along Dunminning Road however this increased velocity may increase flood risk downstream and this is not sustainable
Example for realignment, sustainable?
Re alignment has also been carried out at Connswater River in East Belfast which made the river more canal like which is not environmentally sustainable but it is economically sustainable as it has reduced floods for people living there
