GEOG 200 Lecture 8: GEOG 200_Week 8
GEOG 200
1
Tuesday, 24th October
Waters, Rivers ,Dams and People plus (food, health, climate… socioecosystems)
We have erected thousands of dams, dikes, and levees
Dam: any obstruction placed in a river or stream to block the flow of water so that water can be stored in a reservoir
- To prevent floods, providing drinking water, allow irrigation, and generate electricity
- 45, 000 large dams have been erected in more than 140 nations
Only a few major rivers remain undamned
Levels in the reservoirs may drop dramatically
Non productive, very hostile environmental – for human use and ecologically
Major Benefits of dams
- Power generation
- Emission reduction
- Crop irrigation
- Drinking water
- Flood control
- Shipping
- New recreational opportunities
Major drawbacks
- Habitat alteration
- Fisheries declines
- Population displacement
- Sediment capture
- Disruption of flooding (if damage the ecosystems)
- Risk of failure
- Lost recreational opportunities
MOOCs, Books, GROOKs, and you
The sectoral themes so far
- Biodiversity and ecosystem integrity
- Population growth and human development
- Food security and implications for human ecology
- Water and human ecology
- Climate change
The paradox of life
- A bit beyond perception’s reach I sometimes believe I see that Life is two locked boxes, each containing the
other’s key
Us –complex improbable and precarious … and insightful
- Diagram from slides
Case Study of Senegal,
Map of Africa resulted from the scramble of Africa – colonizing power decided to divide the map of Africa
French colony → but UK has led claim on the Gambia river → so Senegal has very limited access to Gambia river
The prime function of the dam is to get rid of salt from the river → really bad for irrigation
Another dam – decrease the flow rate of the river
The dam → impact on fishery and irrigation
Looking at Saint Louis and Richard Troll
People produce frutis and vegetables in rural areas and then sell them in Dakar
But lure of the cities → ongoing with the education system
Education system → French system (main not give them tools in order to survive , but give them their expectation that
they can leave the small communitee)
Large informal sector
find more resources at oneclass.com
find more resources at oneclass.com
GEOG 200
2
Local manufacture of fishing boats
→ chaotic scene when the fish and the boats are brought back to the shre – mixed with bird feeses
and the tie takes everything out in
organic waste → will feed the fish
unsavory organic “feast” on the beach twice a day but ends up as nutrition for sea population
Key points of this story: transitions on the Senegal River
- Human development
- Power imbalances
- Adapted human socio-ecosystems
- Water system change
- Food system change
- Economic system change
- Socio/political system change – delocalization
- Public health, food, and water borne disease
- Innovation: small is beautiful? (but is it adequate?)
- Local autonomy is adaptive (but is it sustainable?)
Manantali Dam, Mali data from International Rivers
• Bafing River (Senegal Basin)
• 200 MW power
• 1300 km of transmission lines
• to the capitals of Mali (Bamako)
• Mauritania (Nouakschott)
• Senegal (Dakar).
• 1460 meters long x 65 meters high.
• Reservoir storage 11.3 billion mÑ and surface 477 kmÇ.
• https://www.internationalrivers.org/resources/a‐case‐study‐on‐the‐manantalidam‐ project‐mali‐mauritania‐senegal‐2011
Purpose:
- To irrigate an area of 3,750km2
- To generate hydropower
- To allow navigation between the cities of St Louis and Kayes
Diama Dam, Senegal River
• OMVS – completed 1986
• built at the river delta to prevent saltwater intrusion, to support irrigation and extend river navigation.
Sahel
- Arid environment
- Limiting factor of moisture
- Pastoralism – main living activities in the area – culturally a very sophisticated way of using the local limited
ecosystem
- But no the access to land has been limited and regulated → the richer elite/the local elite now bought the best
land and push people out of their lands → driving cause of desertification in the Sahel
Richard Troll
- Most of the water comes from inland Africa
- Rainfall – seasonal so seasonal river and grand deal of variation year to year
Rice became the dominant crops → densed but failsplantations
Easier to sell
Lots in nutrition
But not basic food stock
Elements of what they are tempting to achieve → lcocal microscale technologies
- Like micro dams
- All of this is just
If there is a groundwater – which happens in the area
- Same principle of micro dams but here requires innovative technology
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Waters, rivers ,dams and people plus (food, health, climate socioecosystems) We have erected thousands of dams, dikes, and levees. Dam: any obstruction placed in a river or stream to block the flow of water so that water can be stored in a reservoir. To prevent floods, providing drinking water, allow irrigation, and generate electricity. 45, 000 large dams have been erected in more than 140 nations. Non productive, very hostile environmental for human use and ecologically. Disruption of flooding (if damage the ecosystems) Food security and implications for human ecology. A bit beyond perception"s reach i sometimes believe i see that life is two locked boxes, each containing the. Us complex improbable and precarious and insightful. Map of africa resulted from the scramble of africa colonizing power decided to divide the map of africa. French colony but uk has led claim on the gambia river so senegal has very limited access to gambia river.
