The US census indicates a 10% increase in population over the past decade and the city’s own websites says that 2009 assessed valuation of permitted construction of 18.4 million and the median house value is over 300K.
They have had lots of development all over, it doesn’t have to be next door to the lot, run off into creeks will come from many more points, but the overflow is going to happen in that flood zone at the confluence of those two creeks.
They could have just bought him out when he offered to sell it to the city. It’s in their development plan, so you tell me why they didn’t take him up on the offer.
Because somebody saw a chance to create a “nuisance” property, buy it up cheap and then resell it to the city.
If you start getting condo and high-density encroachment into the older subdivisions (and that's probably more likely along the commercial corridor) you could see some increased runoff. But this is not a flood zone and we're not talking about a huge creek. During those 2009 floods the normally dry wash next to our property was a raging river (and got into our crawlspace).
I cruised around the Roswell website for awhile, but didn't see anything in the development plan that had an impact on this particular property - other than it being within the Alpharetta Highway commercial corridor. Source?