Neighbor Is Flooding My Yard

So my backyard is shared with my neighbors essentially, only a fence separating it. She is a fairly old lady, but extremely rude and has no intention of ever wanting to talk to people or just be kind to anyone in the neighborhood.

Well a few days ago I noticed my backyard had standing water in it. I thought maybe I had some pipe leaking. I went through a lot of checking and such but found nothing.

Yesterday I saw a small stream of liquid hidden under a tree flowing from my neighbors side of the fence into my yard. This is absolutely the culprit obviously.

So I went to talk to my neighbor and told her that she has some kind of leak or maybe a hose left on or something. She basically slammed the door and has no intention of ever shutting it off.

My backyard has become unwalkable without trudging through clay and mud now. I am worried it's just gonna get worse!

Is there anything I can do??

Edit: Greenville, SC