I've long thought that instead of building the underground oil pipelines in Canada and the USA, we should be building pipelines underground that can transfer water from places that get flooded, to areas (like California), that are running on empty. That way, flooding in certain areas could be greatly reduced, and the places that urgently needed the water would be greatly helped.
With that said, civilization itself could be a big factor as to what's happening in California. I found a couple of interesting quotes on what man is doing that leads up to the droughts that can lead to once-fertile lands becoming deserts:
"...During the first four centuries AD, the Romans ruled much of North Africa, which supplied most of the grain for the Empire. Then the crops began to fail as the fragile soils were overploughed and overcultivated. Trees had been cleared to provide more land for cultivation, yet these trees were vital for regulating the amount of water in the soil, and also prevented soils from being blown or washed away. The soils which were washed away by the rain ended up as silt in the sea. The Romans were unable to stop the silt from filling their harbours, so within a few years their bustling, prosperous trading ports became ghost towns, with the sea moving ever further away as the continued deposition of silt led to the constant retreat of the sea.
Today, the same things are happening, but as we have become more civilised, we have become much better at creating deserts. Around a quarter of the South American rainforest has already been cut or burned down in order to make land available for cultivation. The rainforest soils are very fragile though, and need the trees to hold them together. Once they are removed, the soil can be washed away very quickly. Moreover, rainforest soils are not very fertile. Within a few years of use, all the nutrients in the soil are used up, meaning that crops can no longer be grown.
The soil is little better for keeping cattle. Forest soil produces 22 kilos of beef per hectare, as opposed to 270 kilos of beef on a European farm. Yet between 1966 and 1986 - 50,000 square kilometres of Brazilian rainforest were cleared to make way for new cattle ranches. Even now, when we know this, an area of tropical rainforest the size of one hundred football pitches is being destroyed every minute. The long term effects of deforestation are being ignored by governments, farmers and corporations looking to make a profit out of the first few years of land use. What makes this destruction even more pointless is the fact that a properly managed area of Brazilian rainforest can produce ten times more food than land that has been claimed for use as a cattle ranch..."
There are more people living in the State of California, than in all of Canada. How many thousands of acres of trees have been demolished to make way for multi-million dollar homes? The trees get cut down, you go a couple of years without enough rain, then you get a ton of rain all at once which causes mudslides because the dry soil can't handle it and the trees have all been chopped down.
There simply isn't never-ending resources available to suffice for that many people living there and something has to give.
