This document discusses opportunities for urban farming in coastal cities. It notes that traditional farming will likely not be able to meet the food demands of growing megacities in the future. Coastal cities offer opportunities for urban farming using floating platforms in shallow coastal waters and exploiting the layers of fresh and saltwater in estuaries and river deltas. Specific opportunities highlighted include using river deltas in Asia for rice farming and harnessing the Nile River delta's freshwater resources.

1. URBAN FARMING
Opportunities I: Coastal settlements

2. Present and future
• Existing urban farming solutions are created for existing problems.
• It is clear that currently urban farming is not necessary, traditional
farming can provide enough food.
• The problem is the probably evolving of cities.
• In the near future traditional farming can not provide enough food
for the increased demands.
• In the near future the productivity of traditional farming will probably
remarkably decrease (lack of nutritizer, worsening stage of
farmlands, decreasing amount of water, unsustainability).
• In the near future the cities will grow on actual farmlands.
• In case of megacities, the traditional farmlands will be many 100 km
far from certain parts of the city (increasing energy costs, increasing
mobility).
• These anticipated megacities will be in coastal position.

3. Coastal position I.
• Coastal position used to be considered as a great disadvantage due to
the increasing sea level.
• Moreover coastal position has latent advantages.
• This means that there is a huge empty area next to the settlement.
• Coastal position means that the water is shallow, which can be
advantageous from many points of view:
– Easy to backfill it to gain additional land.
– Easy to install on it floating platform, which can be fixed (mooring)
– It can easily heat up, which can be advantageous from the point of
view of gaining drinking or irrigating water, orr using it up for
algae farming.
– The water content can be different by the coasts than by the deep
sea, especially around river deltas.

4. Coastal position II.
• More than 90% of cities are in coastal position.

5. Coastal position III.
• They are practiaclly the cores of future megacities.

6. Coastal position IV.
• They are mostly connected of great coastal deltas and estuaries or the
probable directon of development will be necessary towards them.

7. Coastal position V.
• They are the most vulnerable areas of the planet. On the other hand,
here the inhabitants must learn how to live on shallow water.

8. Coastal deltas and estuaries.
• On these sites the waters of the rivers get into the seas.
• From many points of view these waters are different from seawater.
• The seawater is salty, thus it can not be drank or used up for
irrigating.
• Due to the salt contain, the seawater is remarkably denser, than that
of the river. The difference is approximately 5%.
• Thus, the coastal water has a special structure by the incoming river
flow.
• It consists of layers. The river water remains in an upper layer, while
the seawater is in a lower layer.
• The certain mixing of the river water and the seawater is quite slow,
thus the river water can cover the sea on many hundred squre
kilometres.
• On this territory the upper water layer can be used up for irrigation.

9. Coastal deltas and estuaries.
• On these sites the waters of the rivers get into the seas.
• From many points of view these waters are different from seawater.
• The seawater is salty, thus it can not be drank or used up for
irrigating.
• Due to the salt contain, the seawater is remarkably denser, than that
of the river. The difference is approximately 5%.
• Thus, the coastal water has a special structure by the incoming river
flow.
• It consists of layers. The river water remains in an upper layer, while
the seawater is in a lower layer.
• The certain mixing of the river water and the seawater is quite slow,
thus the river water can cover the sea on many hundred squre
kilometres.
• On this territory the upper water layer can be used up for irrigation.

10. Zambezi delta.

11. Nile delta.

12. Mississippi delta.

13. Niger delta.

14. Indus delta.

15. Ganges delta.

16. Irrawaddy delta.

17. Mekong delta.

18. Pearl River delta.

19. Yangtze River delta.

20. Yangtze River delta.

21. Coastal deltas and estuaries I.
• The different color comes not from the different salt concentration,
it is the color of organic alluvia.
• The weight of organic alluvia is much greater than that of seawater,
thus it deposes relatively fast.
• It can be used as an indicator: everywhere, where this color can be
sen, the upper layer of water has only minor salt concentration.
• Moreover, this high organic contain alluvia is ideal soil and fertilizer at
the same time (i.e. agricluture of ancient Egypt and Angkor).
• Usage of floating platforms are ideal on these site for food
production.
• Considering the tropic or subtropic climate conditions, the high level
of relative air humidity, the arbitrary amount of water, the absolutely
controllable level of subsoil water and the flatness of these platforms,
the ideal crop will be rice.
• These river deltas are in central position of future megacities => ideal
logistics.

22. Coastal deltas and estuaries II.
• Similar floating ricefields can be installed on river deltas across whole
East-Asia.

23. Coastal deltas and estuaries III.
• Guiyang circle. Full of huge river deltas. Mostly monsoon climate.
Usage the deltas and the rainwater for irrigating floating urban farms.

24. Coastal deltas and estuaries IV.
• Rainwater collection among urban circumstances by artificial
structures. Greywater can be used for irrigation.

25. Nile delta. Other opportunities I.
• The river delta is on sea level. Moreover there is a huge depression in
the egyptian desert under sea level (-130 m): Qattara depression.
• Using the principle of communicating vessels, the water from the
delta can be easily conducted into this depression (pipes in the size of
well-known oil pipes).
• It will be not a lake, but a group of artifical rivers towards the deepest
point of the depression.

26. Nile delta. Other opportunities II.
• The deepest depression
on the planet is the Dead
Sea (-400 m).
• Using the principle of
communicating vessels,
the water from the Nile
delta can be easily
conducted into this
depression too(pipes in
the size of well-known oil
pipes).
• The Dead Sea remains,
but there will be an other
(artificial) river besides
the Jordan through the
Negev desert.

27. Irrigation and seawater. Desalination I.
• The main problem is that seawater
can not be used for irrigation directly
due to its salt content.
• Nevertheless there are simple
solutions to solve this.
• Using glasshouses (quite common in
intensive agriculture) it is posibble to
use up seawater for irrigation.
• The power and the efficacy of the
process is quite low, thus it is not
worth to use it for drinking water
production, but it can effectively
substitute the dropper irigation
systems, which are quite common in
agriculture.

28. Irrigation and seawater. Desalination II.
• The scheme of such an irrigation water producing floating platform.
• There is a high specific surfaced shallow pool, which is painted black.
• It consist a thin layer of seawater under a glass roof.
• The sun heats up the water, it vaporizes, then precipitates on the
inner surface of th glass roofs, then it cn be collected on the edges of
the roof and can be used up for irrigation.

29. A design concept I.
• A design concept for floating greenhouse, using many alternative
source for irrigation.

30. A design concept II.
• The scheme of function.

31. A design concept III.
• The scheme of function.

32. An educational demonstrator.
• The scheme of function.

33. Thank you for your attention!