One of the first puzzles you have to solve, when trying to set up an irrigation scheme, is that of acquiring land for the scheme. Normally, an irrigation scheme requires a lot of land. There are irrigation schemes that occupy hundreds of acres of land. These are the smallest irrigation schemes. Medium sized irrigation schemes normally occupy thousands of acres of land. The truly big irrigation schemes occupy hundreds of thousands of acres of land. We even have irrigation schemes that occupy millions of acres of land. So the question as to how that much land can be acquired needs to be resolved.
In cases where irrigation schemes are being set up by governments, the necessary land is normally obtained through compulsory acquisition. The people whose land is acquired in this way are sometimes shown alternative land where they can settle. At other times, such people are compensated with money, for the land that is acquired compulsorily by the government.
In cases where irrigation schemes are run by private entities, the acquisition of the necessary land can be tricky. The land may have to be leased from the community that owns it. The land can also be bought. Either way, a lot of money is required for the purpose of acquiring the land.
Of course, land acquisition is just one of the many issues that need to be dealt with in the process of setting up an irrigation scheme. There are other issues: including that of incorporating/registering the irrigation scheme. For a smaller irrigation scheme, this may just be a question of going to a site like SunbizFlorida, and trying to set up a company there. The SunbizFlorida website should be quite easily accessible through Sunbiz.org. For bigger irrigation schemes, this question of incorporation gets much trickier.
Then once the irrigation scheme has been set up, you can start entertaining the other questions: including that of getting workers to run it, identifying the plant varieties to cultivate… and so on. Even smaller concerns, like that of procuring spare parts for the irrigation equipment have to be dealt with, one way or the other.