I finally got around to watching the original Planet of the Apes and the first thing Heston and his team do, after deciding there is no life, is to march into the desert away from water. Why do that? Isn't the first rule of survival to follow the water? Do any commentaries ever touch on this?
I'm reviewing the movie on DVD even as I type. They came down into what looks like a large lake in the high desert with another lake at about the 11:00 position as viewed through the pilot's window. The earth date according to the ship's monitor was reading Nov. 25, 3978.
As they scramble out of the sinking spaceship, the camera shows a partial panoramic view of what looks a very large lake with no apparent outlet. The canyon they paddled their raft through was actually just a connecting channel between adjoining lake sections seen from the air. At the top of the ridge after leaving the lake(?), the camera again shows what appears to be the lake they just left. Note: Lt. John Landon did think to leave a small American flag at the lake-shore before they left though.(and before he got lobotomized)
Later in the movie as Taylor, with a still bandaged throat, is trying to communicate with Zera and Cornelious about where he came from, they produce a map that shows the supposed 'lake' in the forbidden zone where his ship sank. As he traces his route for them you can clearly see that the lower western end of the lake narrows and twists and turns until it does in fact eventually drain into the ocean. Because of the geography and topography of the area and the lack of a discernible current, this would have been a hidden route considering their circumstances.
In any case, if they would have discovered and taken that route through to the ocean they would have discovered no civilization and likely died. The route leads deeper into the forbidden zone and away from food, vegetation and civilization. The route they took was actually the shortest possible to food and civilization.
I just found this:
The opening scenes of the original Planet of the Apes (1968) use landscape to disorient the main characters, as well as the movie-watching audience, by showing the humans' spaceship landing in an unnatural-looking deep lake surrounded by red desert sandstone, leading everyone to believe the planet is an alien one.
Filming the opening of the movie in Lake Powell near Glen Canyon, Arizona, a paradoxical deep lake in a desert, unsettles those taking in the scene because it appears natural and yet exists only through artificial involvement (in actuality, the human intervention of damming the Colorado River).
The dry, tree-free and plant-free red rock environment of Lake Powell and the apes' planet is something unfamiliar to the majority of the Earth's population that dwells on the coasts. Having a desert environment suggests a habitat challenging to primate habitation. In retrospect, the desert represents the plant-free wasteland that the Earth has become. http://clarkesworldmagazine.com/blevins_12_11/