Enclosed Yard with Nowhere for Rain to go
A few months ago, we had a pretty huge storm and I found out my backyard floods. My problem is that my backyard is enclosed so there is no way for me to create a drain, that I know of. The walls are made of concrete and are shared by my neighbors so I cannot dig a hole under the concrete, as the water will drain into their yards. I have no front yard access (no gate of some sort to take things from the front of the house to the back). Everything has to be taken through the house if I want it to go in the backyard. I'm wondering if the previous owner had covered over the drain, as I can't imagine a developer would actually design a house with enclosed backyards that doesn't drain out anywhere. My question is:
1) how would I find out if there was a drain? Is there some city entity I can call? I already requested blueprints, but there was nothing for outside the house. Also, almost the entire backyard is covered with flagstone, so that would be a chore to undo!
2) is there a way for me to create some kind of drainage system?
I have attached a picture from google maps. You can see how my house is attached to the neighbors' houses and that the backyard walls are made of cinderblock, also attached to the neighbors' backyards. Any help is greatly appreciated!