That debris in the water looks like seasonal poplar tree (ie "cottonwood") down or "snow", which tends to accumulate on ponds,lakes,rivers,and sloughs in the spring and early summer, at least in my area...so to me, that stuff appears appropriate and natural,and lets me know that it's surely not winter or fall when the photo was shot...just my observation....not sure if AZ has cottonwood trees growing along lake shores and rivers...