The purpose and goals of the preserve are great- conserve water, help animals, provide a place for the public to spend time outside enjoying nature. The 2 people that reviewed before me did a great job of outlining all of those assets.
The reason that I didn't get the Riparian Preserve more stars was because of my disappointment in the activities at the preserve on an average day. I went with a friend and we walked the trails (unfortunately, the water levels were all low at the time and there wasn't too much to look at). We heard birds, but not being too in-tune with nature, neither of us knew what we were looking at (or could we actually SEE the birds most of the time). It's quite possible that I'm just not used to Arizona wildlife yet, but I felt like there wasn't too much to see. But, at the very least, it was a good walk.