After getting the multiple textures to work, I worked on getting all of the rendering passes I would need to compute the final rendering image. This included a background "skybox" render texture, a blurred depth map, and a normal map computed using the depth map. Here are some videos of the results. Currently my bilateral filter which I used to blur the depth map is having a lot of artifact problems, and coming up with good functions to relate depth to blur radius is a bit of a problem.
I will definitely come back to that issue after I have set up all of the other render passes and gotten some sweet looking water.
Here are some videos of the current results.
Basic render-to-texture with normal map computation stuff + skyboxes.
Render to texture + blurred depth map resulting in normals which would define water which looks a bit more watery.
Psychadelic acid-trip normal map super bug. This happened because I was accidentally discarding the depth values for non-fluid pixels, which led to the texture never being cleared so that the normal map texture was only written on current fluid pixels. Whoops.