Why do we only need to be concerned with building OIL pipelines?
Right now there is a massive drought in California and water surpluses in other areas of the US.
If we had a network of water pipelines crisscrossing the country, we would be able to transfer the water across the country. In areas of flood, we could pump out massive quantities of flood water toward the empty reservoirs in the south and west... to help maintain the balance of water supplies across the nation.
If we're willing to build a similar network for petroleum, why not for something equally as vital?