>>1619123About 15 gigawatts of desalination, 5 of that to just pump water into the aquifers and let the current aquifer pumps act as distribution, and then you need some holes. Some big, big holes in the North Eastern part alongside some semi elevated ditches and pipes so that when you have the mega floods you can redirect some of the water towards the giant holes instead of flowing out to the ocean. Then take that water and grow broad leaf trees, like oaks and stuff and get them to be shedding leaves and littering the ground with them. Some shrubbery works too.
Take some of the dirt and rock and use it for building local hills and other remodeling.
There, there's your start. Dig buttloads of ponds, lakes.