Case Study - The Chennogy Cheon River Flashcards
Location
Seoul, South Korea
Population
Over 10 million people
24.5million in the larger metropolitan area
Most densely populated area 17,000 people per square kilometre
Why is it considered one of the greenest mega cities ?
27.8% public parks and gardens in comparison to tokoyo only having 7.5%
What were the reasons for the project?
- Considered unsafe and hazard
- Degraded with age and use
- Govts wanted to improve connectivity between N and S which had become divided over overpass
- Overpass had an impact on 100,000 small businessess competitivness either side of the overpass
- Discintigrating buildings and no green space avaliable
Why was the river covered in the first place?
- Started in 1918 as the river was considered a hygenie and flood risk
- Development was halted during second ww2 and korean war
- Squatter communities colonised the embankments as refugees and populations returned
- Stream fully covered by 1961 by the four lane overpass
When was the project launched?
2003 ambitious 2 year project costing 281 million scheme to restore the river
What were the aims of the scheme?
- Transform the area into a 5.8km ecologically sensitive green pedestrian corridor
- Seoul changing from a development oreinted urban landscape dependent on the car to one that values QOL and importance of functioning ecosystems
What work was carried out?
- Concrete deck was dismantled
- 22 bridges built - 12 pedestrian and 10 cars +pedestrians
- Car use was discouraged in the area with rapid bus lanes and improved loading and unloading
- Water from nearby hanag river pumped to area to create a consistent flow with avg depth of 40cm
Outline the historic zone
- Underground waterways were redirected to create a new stream bed with landscape banks
- Foundations and stones of original bridges were included as a decorative element
- Seating throughout to encourage public use of the space
Outline the middle zone
- Recreation areas, waterfront decks, stepping stones that bridge two banks
- Enviromentally friendly materials
- Fountains, waterfalls
Outline the final zone
- Stream widens to be overgrown and untamed
- Sections of the pier and overpass left - as industrial mementies
- Stream flows into Hanag river wetlands conservation
What is the impact on the water balance?
- Virtually no vegetation - NO ET
- River enclosed - prevented evaporation with only input to the system being from drainage system and waste water
- Flow rates irregular affecting wildlife and sediment balances
- Water quality is poor
Impacts on the catchment after restoration
- Flow rates maintained at a constant rate 120,000 tonnes dumped in daily from hanag river tributaries and ground water from subway stations
- Provides flood protection for up to 200 year flood events - can sustain a rate of 118 mm p/h
- Biodiversity increases by 6.39% between in 2003 and end of 2008
- No of plant spcies increases
- Reduction in avg air temperatures by 2.5 c reducing cars and increased plants leads to reduced uhi
- Increased drainages and et due to plants
- Altenation to inputs to system with added water from hanag river and rainwater
- Biological oxygen supply increases
How was the president of SOUTH KOREA involved?
- Lee Myung Bak included the restoration of the stream in a succesful bid to become mayor of seoul in 2001
What was the problem with the scheme for transportation experts?
- Transportation experts concerned it would cause traffic congestion and chaos and the curt carried 1690000 vechiles a day
