Unknown tube on pool deck

[Zrqtz]

Anybody recognize what the tube in the pictures is? It's not near the filter, pump, heater. It is way on the other side of the pool in the deck.

I just opened my pool, and whenever I turn the pump on, water comes out of this tube on the other side of the pool. Not sure why. Please help!!! And thanks!

[Zrqtz]

I thought I could attach a picture. Anyway, it's a small tube, like a spout on the other side of the pool. It' has always been thee but this is the only time water came out of it. I can't leave the pump on, otherwise it will drain.