![Page 1: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/1.jpg)
The future of deltas in the perspective of environmental
changeHarmonizing human interests and
environmental interest is one of the largest challenges for human
mankind
6th Lustrum of theWaterbouwdispuut
![Page 2: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/2.jpg)
The future of deltas
• Ho Chi Minh City and its estuarine and tidal river delta (a typical example of a growth economy in SE Asia)
• The Southwestern Dutch delta (a typical example of an established protected delta seeking for harmony with nature)
![Page 3: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/3.jpg)
Sai Gon
Long Tau
Vam Co
Vam Co Tay
Vam Co
Dong
Dong Nai
Soai Rap
Can Gio
Vung Tau
Ho Chi Minh City
Nha Be
Go Cong
East Sea
Be
Can Thanh
Hiep Phuoc
Dau Tieng damPhuoc Hoa dam
Tri An dam
Cai Mep/ Thi Vai
Dong Thap Muoi
Thu Dau Mot
The problems of HCM City
March 29 2011Hanoi
![Page 4: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/4.jpg)
Main stakeholders
Shipping
NatureAgriculture
City
![Page 5: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/5.jpg)
Sai Gon
Long Tau
Vam Co
Vam Co Tay
Vam Co
Dong
Dong Nai
Soai Rap
Can Gio
Vung Tau
Ho Chi Minh City
Nha Be
Go Cong
East Sea
Be
Can Thanh
Hiep Phuoc
Dau Tieng damPhuoc Hoa dam
Tri An dam
Cai Mep/ Thi Vai
Dong Thap Muoi
Thu Dau MotDam
Vung Tau – Go Cong: the IJssellake
solution
March 29 2011Hanoi
![Page 6: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/6.jpg)
Idea: “valve” lowers water levels ......
River flow
Tide
5.000 m3/s river flow,
valve 10.000 m2
30.000 m3/s river flow,
valve 10.000 m2
Basin
Dam with valve
No dam, original situation
...... and keeps salt water
outside
Simplified approach
![Page 7: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/7.jpg)
Result depends on: • River flow• Valve size• Basin size
No dam, original situation
Basin 200 km2
Basin 300 km2
River flow 30.000 m3/s
![Page 8: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/8.jpg)
Real situation more complex:
Effect over
whole period
Effect during
springtideNo dam
With valve
![Page 9: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/9.jpg)
ShippingMaximum permissible velocity ~ 4 knots = 2
m/s
Necessary width ~ 200 – 300 m
But: valve closed during flood → locks
![Page 10: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/10.jpg)
Sai Gon
Long Tau
Vam Co
Vam Co Tay
Vam Co
Dong
Dong Nai
Soai Rap
Can Gio
Vung Tau
Ho Chi Minh City
Nha Be
Go Cong
East Sea
Be
Can Thanh
Hiep Phuoc
Dau Tieng damPhuoc Hoa dam
Tri An dam
Cai Mep/ Thi Vai
Dong Thap Muoi
Thu Dau Mot
Possible alternative 1combination of IJssellake and
Haringvliet solution
Idea:• Lowering level HCMC
• Lowering salinity Dong Thap Muoi• Maintaining tide and salt Can Gio• Maintaining shipping route Cai
Mep
![Page 11: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/11.jpg)
Sai Gon
Long Tau
Vam Co
Vam Co Tay
Vam Co
Dong
Dong Nai
Soai Rap
Can Gio
Vung Tau
Ho Chi Minh City
Nha Be
Go Cong
East Sea
Be
Can Thanh
Hiep Phuoc
Dau Tieng damPhuoc Hoa dam
Tri An dam
Cai Mep/ Thi Vai
Dong Thap Muoi
Thu Dau Mot
Possible alternative 2
Idea:• Lowering level HCMC
• Lowering salinity Dong Thap Muoi
• Maintaining tide and salt Can Gio
• Maintaining shipping route Cai Mep
![Page 12: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/12.jpg)
Provisional conclusions• Idea promising for lowering water levels with
moderate river flows• For extreme river flow, it will be difficult
• For detailed studies consistent data needed (salt, velocities, discharges, ….)
• Take other issues into account, e.g. subsidence
Dutch experience: soil subsidence more important
than sea level rise
![Page 13: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/13.jpg)
The Dutch Southwestern Delta
Perceived problems
![Page 14: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/14.jpg)
The Dutch Southwestern Delta
Perceived problem: no
salt-fresh water gradient
![Page 15: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/15.jpg)
The Dutch Southwestern Delta
Perceived problem:Stagnation due to
absence of fresh/salt water
gradient
![Page 16: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/16.jpg)
The Dutch Southwestern Delta
Perceived problem:Starving intertidal
areas
![Page 17: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/17.jpg)
The Dutch Southwestern Delta
Perceived problem:Restoration of intertidal, low-
dynamic regions
![Page 18: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/18.jpg)
The Dutch Southwestern Delta
Solution: restore intertidal areas by depoldering but
polictically unacceptable
![Page 19: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/19.jpg)
The Dutch Southwestern Delta
Political solution: restore intertidal areas by creating these areas in the current outerdike
space!Nonsense!
![Page 20: The future of deltas in the perspective of environmental change](https://reader030.vdocuments.us/reader030/viewer/2022032606/56812eff550346895d949dc9/html5/thumbnails/20.jpg)
Conclusions
• Growth economies are facing a challenging time: how to combine economic growth with environmental concerns
• Established economies are facing a challenge as well: how to restore environmental values against economic interests