I am now studying the northern end of the Gulf of California as a likely location for solar-heated evaporation rafts. Remember that I have a design that looks like it will work by heating the thin layer of water above the submerged solar absorber plates that are kept at the chosen depth by floats that protrude through the water surface. To see how I got to the outlet of the Colorado River let's review all the other locations that I have considered. The solar-heated evaporator raft idea was originally conceived as a remedy for inadequate orographic rainfall, where moist air is pushed up over mountains, encounters reduced atmospheric pressure, expands, cools, and water vapor condenses. The thought was that the rafts, located in coastal waters, could lower the dew point sufficiently, so that the condensate would form droplets heavy enough to precipitate. This would supply water to people living at high altitudes, with the excess supplying people who live at lower altitudes along streams and rivers. Vapor transport to high altitudes overcomes the cost and power demands of desalination at sea level and pumping the product to higher altitudes. An example would be the Arabian Sea off the western coast of the Indian peninsula. The summer monsoon winds rise up over the Western Ghats but sometimes leave little rain on the Deccan Plateau. The poor farmers just watch the silvery clouds passing overhead. A little extra water vapor supplied by evaporator rafts might trigger rainfall.
The 2012 drought in the central plains of the U.S. shifted my attention closer to home. There is little orographic rainfall here. The moist air is lifted by convection, resulting in thunderstorms, and possibly tornadoes. I thought of increasing the convection by laying black plastic film solar absorbers on the ground, but that would increase the damage and loss of life from storms. I could see that this was getting out-of-hand when I suggested that a monstrous multi-state system of absorbers might spread out and weaken the storms when I did not understand how absorbers in fixed discreet locations would interact with air masses moving over them due to wind. Furthermore, the proposed location of rafts along the Texas - Louisiana coast would increase the summertime humidity, which is already excessive. And then we had flooding in Missouri in 2013. Enough already! Move on.
I noticed that the wind direction was often from the Pacific into San Francisco Bay. How about rafts in the relatively calm water of the bay? After some study and observation, I could not see what good they would do, so I dropped this location. But it got me thinking about the headwaters of the Sacramento River, which seems to have adequate flow. But the Colorado River does not. Could some of the abundant Columbia River system be evaporated and sent to the Colorado River watershed? This raises the question of whether you are robbing one system without sufficient benefit to the recipient system. And then we had the torrential rains and flooding on the eastern side of the Continental Divide. The headwaters for the Colorado River is on the western side of the divide, so apparently no benefit. But a warning to not mess around with stuff you don't understand.
So now I'm observing the wind and rainfall in the desert area at the outlet of the Colorado River into the Gulf of California. There is little discharge because the Colorado River supplies the Imperial Valley irrigation via the All American Canal. Maybe the rafts can do some good here. At least the ocean would supply the water.