I used to have some business with Cargill, and got a tour of their facilities below. They had some buildings from the early 1900's, but also a state of the art facility for removing salt from brine. They pumped the bay water into those pools, and if I recall correctly, it took six years for the water to evaporate correctly, and leave a proper layer of salt behind. Then, when the salt was ready to harvest, they ran big harvester machines out that peeled the salt right off the bottom. Great fun, but it always ooghed me out that the nice clear white salt we put on our food started as sea water in the South Bay. I believe Cargill has cut a deal with all the local governments to return the pools to wetlands.