Yes, it's a swimming pool and yes it's all very cleverly reclaimed land, around where the Singapore Grand Prix is run. As an example the famous Raffles Hotel mentioned above is on the corner of Beach Road, actually it's address is No.1 Beach Road and originally it was indeed on the side of the beach. Now I reckon it's about at least two miles inland ! In all fairness though it's not all modern development as it was pre WW2 when it was actually on the Beach.
Absolutely great city though and to me this is a beautiful photo of the modern city, thanks for posting.