Flashcards
Rivers KIQ2 - Multi resource flash notes (MEKONG)
Cards in this deck (10)
- 1Opening notes for Mekong River, BangladeshSouth East Asia's largest river at 4350km in length
8th largest in World
6 countries, however, share the Mekong and compete for the resources it provides
Largest city on the river Phnom Penh only has 1.1 million inhabitants, the impacts of rapid population + fast economic growth are only just now beginning to show for the Mekong - 2TransportationTransportation opportunities on the Mekong are limited as the river is challenging to navigate beyond Phnom Penh
In dry season, when river flow conditions are low, there are shifting sandbars and reefs
When water levels rise, particularly during the wet monsoon period, rapids form at Si Phan Don which create a barrier to shipping - 3Industrial and economic developmentIndustrial development limited in the earlier part of 20th century, however emerging economies such as China and Vietnam have moved to exploit the Mekong's resources
China population growth = 1% and economic growth at 10.7% figures for 2007 and 2006
First dam built on river at Man Wan in China in 1993 - 4Residential development55 million people live in Mekong river basin
Many areas along Mekong high risk flooding - residents have to contend with this almost yearly (e.g. Bangladesh)
Population will rise = more demands on water supply + infrastructure
Raw sewage already an issue - enters river system causing disease - 5Recreation and leisureTourism is growing rapidly in area = lots of economic benefits
However tourist developments and demands placed on services = conflicts with requirements of locals and traditional activities e.g. fishing
Area is receiving funding from Asian Development Bank to conserve natural environment and promote sustainable development strategies. - 6Energy development on the MekongMekong is great for Hydroelectric power!
Steep relief of area and large volumes of water allow for great discharge sufficient to turn turbines of HEP dams
Only 5% of the Lower Mekong Basins HEP potential has been developed - all projects thus far have been on the tributaries
Positive impacts of dams = electricity generation, irrigation and the regulation of flooding as water levels can be controlled
Negative impacts of dams = Traps valuable silts behind that would otherwise be deposited as alluvium downstream, starves downstream of silts and sediments = increased erosion, disrupts the movements of aquatic animals such as fish. Dams also built to act as reservoirs + provide water supply - China using their dams to siphon off water, thus reducing the volume of water and thus water supply to countries downstream e.g. Laos
Currently 13 HEP stations on Mekong, only 2 on main river - belong to China - 7Fishing and the MekongAnnual fish harvest is 2 million tonnes - twice the catch from the North Sea
Over 1200 species of fish can be found in Mekong
1 million people in Cambodia depend solely on fishing for a living
70% of rural households in Laos supplement income through fishing - 8Fishing and the MekongFish are abundant here because:
Mekong has very large range of flow conditions due to dry season and monsoon season
During the monsoon system the Mekong floods, increasing the area of habitat available for fish. Most of the floodplains are forest which provides leaves for fish to feed on.
Spawn at end of dry season, so floods then carry them to floodplains.
Bigger floods = greater area of forest land fish can access = greater numbers of larger fish - 9Fishing and the MekongBut then there were dams....
More dams = more control over water flow = smaller, more controlled floods as HEP is generated at the same levels all year round requiring consistent flow of water through turbines - requires rainwater to be held in reservoir during the dry season - 10Dams are harmful to fish/the aquatic ecosystem because...They affect the flow of sediment - sediment collects behind the dam and causes the waterbed in front of the dam to become scoured and rocky meaning no aquatic plants can grow, also removal of sediment also removes nutrients it contains meaning environment no longer suitable for fish/other aquatic life
Obstructs migration of fish, fish can be killed by the turbines and machinery - modifications can be made though such as fish ladders
Can also trap fish and leave them vulnerable to predation as it slows the rate of migration
Affects the general overall water quality, particularly in reservoir behind the dam:
Sediment collects behind the dam and so can pollutants which have leached into local groundwater which then enters the main river channel.
With particularly deep structures, thermal stratification occurs as there is no current to mix the water. Consequently deeper areas become cold and anoxic due to poor oxygen circulation.
Areas closer to the surface are warmer than usual. Release of the deep cold H20 v. problematic for fish downstream due to poor O2 content + pos. toxins
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- Flashcards on Rivers KIQ2 - Multi resource flash notes (MEKONG), created by Lotty Gilroy on 11/05/2015.
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- Lotty Gilroy
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