If the house is in Garrision Greene, I have lived in this development for the last six years, and I'm very happy.
Here's my input on your questions above:
1.) I've seen significant flooding happen on the turnpike entrence and by MaGerks up the street. In terms of flooding in the development, the elevation is very high, and there have been no issues anywhere in the development.
2.) I was very nervous about the noise prior to moving into my house. Let's be honest, the property is close to the turnpike & the train. The septa train really isn't a concern from a noise perspective. The highway noise would depend on where the townhome is located in the community.
I really enjoy living here, we have great neighbors, and are in a wonderful location.
I would highly recommend living in this community.