system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout 3] Why is Washington DC a barren desert while Point Lookout is a swamp?

Washington DC and Point Lookout are only about 60-70 miles away from each other. Washington DC was also built on a swamp. Without constant maintenance to keep its current climate, the swamp will once again reclaim the area.

Nuclear war of course would interrupt regular maintenance of the waterways, and once these failed, Washington DC should be a flooded swamp with humidity through the roof. However in Fallout 3, Washington DC is depicted as an arid, barren area seemingly devoid of water. And yet Lookout Point, only 60-70 miles away, is a lush area teaming with plant life.

Even assuming that the radiation from so many bombs being directed at the capitol of the US during the Great War makes it almost impossible for anything to grow there, it should still be a swamp, albeit a dead swamp. Its still going to be very wet and humid from both rainfall as well as from the waters of the Potomac.

Why is Washington DC so dry but Point Lookout nearby is so wet?
gpt
>Even assuming that the radiation from so many bombs being directed at the capitol of the US during the Great War makes it almost impossible for anything to grow there, it should still be a swamp, albeit a dead swamp.

It is possible that the shock from the impact of that many nukes altered the course of some rivers and underground water drainage patterns to dry out the DC area.

Another possibility is that a combination of the heat and impact from the nukes altered and compacted the soil, making it harder and less porous.  This would cause more rainfall to run off down the Potomac and into the ocean instead of pooling in a swampy area.