If I can find a pond with no apparent signs of anyone maintaining the pond, I will put them there. Otherwise I am thinking of the downstream side of a long mound in the creek bed. There are trees and bamboo growing all over the mound, but I might be able to squeeze a couple plants in the area just downstream from this. This river hasn't reached flood stage in a long time. Several years ago it broke its banks at least 5 feet over flood stage, but usually it might just go up a couple feet after a storm and then gradually go back down.

Lilium humboldtii ocellatum

Daylilies grow well near gray water. The wild orange ones do very well.

Beca, thanks for posting. I believe you need a more specialized forum to consult with regards to your garden. Xeriscaping seems to be far more suitable for your area. You need to find plants that do not require as much watering and obviously plants that can withstand very cold nights and very hot days. A little design tip of mine. I take a photo of the garden in question and I take it from the angle you see it the most. Like from your door or your window. Then I blow up this photo in a black and white photocopier. And then I start drawing directly on them. So for the area you need to block off from view, take a pencil and draw on paper blocks, squares, rectangles, columns, rounds and basically move them about on the photo until you are satisfied with the positions. These figures represent plants. Columns can be a trellis, post, vine, tree, rounds, squares, rectangles are hedges, grasses, etc.. and for the moment, forget about flowers. When you do figure out how to position the plants, it's time to go to your local nurseries to consult on suitable plants. Keep in mind, avoid trees because this is a septic tank area and roots can do a large amount of damage to pipes and tanks. Also keep in mind that in Arizona -- as I believe, you need plants that do not require watering - so this must be either cacti, agave, echeverias and other similar plants that get it's moisture from morning dew or mists. I do hope these are helpful tips for you.