Cities need Freshwater to Grow

(Matias Volco) #1

The point has been made that cities depend on freshwater resources, as well as landfills and agricultural land.

I contend that for cities to grow and be established after the industrial revolution they are indifferent to natural resources and rather depend on human built infrastructure

Just as in the desert fresh water can be managed so can in the ocean, not only by rain collection which depends on rain prayers, but on hands on solar powered desalinization

Jellyfish barge
or any translucent dome upon the sea

Naval Forts and the Pacific
Futuristic tower designs for Seasteads
Homestead on the sea basics

That’s an old pic of Hoover Dam, and after browsing that pnat site, i’d stay away from them. Yes, i am in favor of growing some plants as food on a seastead, as i have said before.

(Matias Volco) #3

What does it matter that it’s old, the point is that by managing (building a dam) the little fresh water in the desert Las Vegas was able to grow.

Any translucent dome upon salt water will produce fresh water cheaply. Applying economics of scale, enough water can be condensed to fuel a city’s freshwater resevoir.

Rainwater also helps, if managed appropriately. Singapore’s precious land surface is in more than 15% dedicated to reservoirs.

The point is that it is management not natural accesibility the deciding factor.
The opposite example of Singapore are villages not so far from that city and all the way to Africa and South America which have abundant river and rain freshwater but endure a lasting clean-water crisis.

(Sheldon Robertson) #4

Soooo… Now I am scared to click on the link. What’s the problem with the jellyfish barge page?

(Matias Volco) #5

It’s not as if there is no fresh water in the middle of the ocean, just as there is fresh water in the desert.
Inland in dry areas fresh water can be found underground or in rivers that pass through. But there is a lot more in the ocean.

In the ocean, or in the many existing cities located on a desert coast (Saudi Arabia, Northern Chile, Namibia) fresh water also exists, in gaseous state being constantly evaporated on the surface. The ocean surface is where all of the World’s rain water originates from. It’s a matter of capturing just a little bit of it to quench an entire city’s thirst.


It’s hype, the page and their projects are optomised for sales, not optimal productivity. For instance, they use tyraps to hold the water tubes, but tyraps are nylon and break down in sunlight. They claim the small flooded flat plate distillers make 150 liters per day, by using the plastic barrels they float on, but there’s no connection from the flat plates and the barrels, and the flat solar collectors aren’t tracking the sun. And they mention the “cool sea water”, but the water off Bahamas right now is 80F. On one pic there’s someone standing on a waterpipe, remember it’s held up with small tyraps. Their tiny self-distilling floating mushroom planters have no freeboard, the one on the right is shipping dirty water over it’s side. There’s just not enough quantity of plant vs the floor area of the thing to justify it. One pic shows a dome-thing covered in plastic film, i have tried various films, don’t count on them lasting one year in direct sunlight.


Matias, i know a lil bit about water, i have been making my own from rain and creek for the last 3 years. I’ve been using plain, carbon, and RO filters.

I have figured out how to put the same surface area of a 30ft dia pond into a 2x2x4 ft cabinet for distilling. Still working on the condensing side of it.

(Wilfried Ellmer) #8

@Matias, i see that you have given a lot of thought to that and like me, you are intrigued by the fact that in this decade we are the first time in the history of mankind in a position where it is completly feasible to build a human city that is not “parasiting” some kind of a natural resource ( like a river, fertile soil, fish grounds, etc…). A well planed and managed city can work without taking resources from natural eco sistems and be no longer a threat to the environment. This is a fundamental game changer and it comes exactly at the moment we need it.

(Wilfried Ellmer) #9

A amazing project - showing that even low tech can bring up great solutions…Oceanic cities will be among the first to showcase this technology.

(Wilfried Ellmer) #10

simple demo water production by condensation it works even better on the ocean surface than on moist ground…


In my city design I came up to the water problem. But I don’t see any issues with simply installing a marine desalinator. They run from $4,000 to $20,000 for a boat type unit. They run on relatively low power.

Overall in my design I’m using technology for power generation, sewage treatment and creating fresh water for both farming and household use. I like the idea of a 4-plex, because price/performance works well for about 10 people. Power, sewage and fresh water all together should be about $50,000, which is $5,000 per person. All the units need a few hours maintenance every month, and probably have a service life averaging 10 years, so it comes to about $1.50 cost per day per person.


I think i am up to $20 cost on mine, not counting the typical CYA filters on the backside, a UV light, and a couple solar/battery powered $20 pumps and a pressure tank. I prolly will integrate a chilled water system with it, to provide extra energy and boost the efficency. The chilled water can then be used for air conditioning and food storage. That chiller can be made from cots stuff for under $200, i suspect. Even if the final cost is $500 total installed and running, it’s not $5000, and it has good side benefits.

(Wilfried Ellmer) #13

The idea is not to burn oil to run a machinery that produces fresh water. The idea is to use the sun to do the trick without machinery similar as it happens in nature… The marinea culture includes low eco footprint …


You are replacing automation with human labor. Also, you are going to have problems with purity in large scale storage operations if human hands are involved.

All trends are for hands-off automation. How about this: When we have a seastead, you go fuss with your water plastic every day to get a liter of water. And I’ll set back on my lawn chair after a good hot shower, and sip my iced tea.

(Matias Volco) #15

Replacing fossil fuels with crude solar power (or with the means to capture it, that is, a translucent dome).
Why would dirty human hands need to touch our freshwater supply if done through passive solar condensation?


I just assume hands because I once used a poly cover for farm plants. It needed adjustment frequently because of the wind.

Let’s focus on the goal here. How many gallons a day do we need? I was checking websites for guidlines for boaters. They say 10 gallons to 20 gallons per day for boaters who do not do laundry. A land-based house uses about 80-100 gallons per day.

Octavian from your marina experience, how much water would you advise a boater going out for a 7 day trip?

Also, as a marina, incoming boats expect fresh water, laundry and showers, right? That’s standard marina service.


Ok, I think I found another factoid. For solar distillation method water generation, generation capacity is about 1 gallon per square meter of collector per day.

Most websites note that solar cells powering membrane distillation is about double the capacity.

So far - 40 gallons per day per person, so it takes 40 square meters of solar evaporative technology. Roughly 9 square feet per square meter, so 360 square feet solar evaporative area per person. About 30% of the overall area of the city is going to be water generation.

I’d still advocate generating power, and using that for a machine to make the water.

(Matias Volco) #18

I don’t think the best way is to pre-design a new array of systems for oceanic civilization and then apply it.
Rather, let’s begin with proven existing methods while experimenting with more sustainable ones.
30% of some entity’s surface used to collect water is not that bad, but I wonder how you got that percentage as the domes could be spread out in an open way (where’s the limit?)


Why must they be domes? And how will you deal with them sloshing all the water out during a 5 day ride thru a hurricane? Who will go find them all after they have been dispersed across the ocean by the storm’s 130mph winds?


Ok. I’m just trying to calculate what resources are needed.

Do you have any input on the numbers?