Mystery river fly

Insect on gate
I found this beautiful creature sheltering from the rain under one of the curlicues of our wrought-iron gate. It is some sort of river fly but I haven’t conclusively identified it more specifically. Any river fly experts out there? It has two long tails, unlike the common mayfly which has three, and apparently only one pair of wings. I found it nowhere near a river so I an guessing it is one of the river flies that will inhabit standing water. Anyway, whatever it is, it’s a beauty! Here’s a close-up:
close-up of insect in gate