Gaining more land by draining wetlands

Question

I’m building a country located in today’s Argentina. It is as developed as Canada or Australia, and has several times bigger population than today’s Argentina.

Which brings us to the problem:

Argentina has limited cropland area (highlighted in red):

Before the industrial revolution in the mid-1800s, the vast majority of the population lived in this red C-shaped fertile region (like they actually do in Argentina). The other regions (green on the map) are wetlands, deserts and other lands non-suitable for agriculture.

In the 1880-1910s, there was a huge population boom caused by the industrial revolution. The cities started to grow unprecedentedly as well. The nation’s leaders realized the country may soon run out of croplands.

To gain more land, the country would gradually start draining the wetlands that are located in the middle of the red C-shaped cropland region.

There are 2 options of what to do with the drained wetlands:

1. The cities located on croplands would keep growing, turning croplands to built-up land. The wetlands would be then converted into fertile croplands – which I don’t know whether it was possible at that time. Because I think that all nutrients are washed out of the wetlands.

2. The wetlands would be converted into urban and industrial areas, leaving the croplands for agriculture.

Which is more feasible and realistic?

Answer 1

It is certainly possible to turn wetlands into fertile farmland using 17th century technology, because that’s when the Fens in eastern England were first drained and used for farming. So that’s a much likelier option than relocating cities, which is very difficult and expensive.

Answer 2

It will happen organically and gradually.

As demand for land grows parts of the wetlands will become economical to convert. What they are converted to depends on what is needed.

I think typical result would be farmlands with a network of small towns. But there might be one or two larger towns that might then for some other reason keep growing. There might be legalized gambling. Or the government might decide to build new properly planned capital on the new land.

It will not be all farmland because the farmers will need services and logistics, so a network of small towns will be needed and if there is shortage of living space will probably keep growing until agriculture becomes more mechanized and less labor intensive and people will start migrating to larger cities.

It will not be all cities since such artificial cities are not very appealing places to move to. They cannot generally compete with established cities with extensive established services and rich culture. Societies, like trees, prefer to grow from bottom up.

Answer 3

The better option is to allow this land to be mostly farmland. For a real-world example during the same time period, consider the conversion of California's Sacramento-San Joaquin Delta to farmland. Draining and diking the land caused the ground level to sink, in some cases to 25 feet below sea level. As was shown during Hurricane Katrina in New Orleans, it is much safer to build cities above sea level.

The drained land is quite valuable as farmland.

You also have an even bigger opportunity. During the 1880s - 1910s, companies serving farmers in California's Central Valley built irrigation systems that transported snow melt from the Sierra Nevada to the Central Valley. Bonds were issued to pay for the largest dams; the bonds were repaid from hydroelectric revenue. How much of the "too dry" areas can be irrigated using snow melt from the east side of the Andes?

In order for the country to remain as prosperous as Canada or Australia, you will need to ensure rule-of-law, property rights, low or moderate taxation, and stable price levels. This will require major changes to the political history of the country. But having done this, by the 1970s there will be the possibility of using nuclear power plants to desalinate sea water for irrigation purposes. You will need about 3,000 kiloWatt-hours of electricity to produce each acre-foot of water, or about 1 kiloWatt of generating capacity per drip-irrigated acre. This would be viable for high-value crops, but not for low-value crops. This would allow areas that are closer to the Atlantic (and further from the Andes) to be irrigated.

By the 1980s, California's Central Valley was adopting Israeli drip-irrigation practices. This cut irrigation water needs by 40% - 60%. California also developed irrigation practices that both cut water needs by 40% - 60%, and improved crop yields by reducing the time the rice was flooded. Your farmers can use these techniques to double the area that can be sustainably irrigated.