Contemporary Urban Environments - Urban Drainage Flashcards
What is a sustainable urban drainage system (SUDS)?
This is a relatively new approach to managing rainfall by using natural processes in the landscape to reduce flooding, control flooding and provide amenity for the community.
What are the two types of SUDS?
Grey SUDS and Green SUDS
What are two examples of Grey SUDS?
1) Permeable pavements
2) Storage tanks
What are permeable pavements?
Precipitation falling on surfaces is infiltrated through permeable paving, where it is either filtered and stored in the stone or tanks below or flows on to grass channels before joining a part of the SUD system. This can be suitable even in the most densely built-up areas.
What are storage tanks?
Hold rainwater for slow release back into the drainage system. They do not provide wider benefits of green infrastructure and pumping may be required to empty the tank into the drainage system.
What are two examples of Green SUDS?
1) Swales
2) Green Roofs
What are swales?
Shallow, broad and vegetated channels designed to encourage infiltration and runoff moisture. They can be used alongside roads, footpaths or railway lines. They aim to protect areas downstream.
What are green roofs?
Part of a building that is covered with vegetation. Provides an area to offer retention of water, as well as providing habitats, insulation and amenity space.
What is the Thames Tideway, London?
- A new 25km sewage system built underneath the River Thames to capture, store and transfer any excess sewage and rainwater that usually flows into the river.
- Will help reduce the amount of untreated sewage that is released into the Thames.
- Cost $4.2 billion (funded by Thames Water).
- Started in 2016 and aims to be completed by 2025.
- Increased levels of noise and air pollution, congestion and many believe green infrastructure would have been sufficient.
What is the case study for river restoration and conservation?
Cheonggyecheon river, Seoul, South Korea
What is the context of the Cheonggycheon River?
- It was a highly used seasonal river that dissected the city.
- After increasing levels of air/water pollution and canalisation, the river was concreted over and a highway was built over it during the 1970s.
What were the reasons for the Cheonggyecheon River Restoration Project?
- Increased prominence on the quality of life of the people.
- The concrete covering posed safety risks (repair or remove).
- Wanted to improve connectivity between the city.
- Little green space and the area was becoming derelict.
What were some key features of the Cheonggyecheon River Restoration Project?
- US$281 million scheme to restore the river.
- 22 bridges were built to improve connectivity (12 pedestrian and 10 car and pedestrian).
- Car use was discouraged.
- Rapid bus lanes were added.
- Discharge from Hanan River was used to create a consistent flow.
- Recreational green spaces, such as the waterfront decks, stepping stones, fountains and waterfalls.
What were some pros of the Cheonggyecheon River Restoration Project?
- Transformed the areas into a 5.8km ecologically sensitive green pedestrian corridor.
- 2.5 degrees C reduction in average temperatures, due to the removal of many cars.
- Noticeable improvements in air and water quality.
- The ‘Restoration Citizen’s Committee’ ensured public opinions were considered in planning stages.
What were some cons of the Cheonggyecheon River Restoration Project?
- Increased traffic congestion within the city as the old highway carried 169,000 vehicles daily.
- Limited consideration of certain groups e.g. older people, people with visual impairments and people with mobility problems.
What was the economic sustainablility of the Cheonggyecheon River Restoration Project?
Despite its central location the area had fallen behind the rest of Seoul in terms in economic viability. Since the end of the project, development capital has been invested in residential construction and property prices have risen at double the rates elsewhere in the city. The number of businesses in the areas closest to the restoration work has risen, compared with decreasing trends in most other city districts.
How was traffic impacted by the Cheonggyecheon River Restoration Project?
Speeds in the central business district slowed by only 12.3%. Bus and subway train usage has increased. The stream-side walk is an attractive alternative to street level journeys, and there is more pedestrian activity in the area. A 2005, public survey showed respondents overwhelmingly noticed improvements in air and water quality, noise and smells.
How the environment Cheonggyecheon River Restoration Project?
The stream has re-established lost habitats, plant and animal species have reappeared, and it has become an urban wildlife haven. Schoolchildren have access to a valuable educational resource through the ecology embedded seamlessly within their urban environment.
