A blue Wednesday

A story behind: It does not happen very frequently when the estuary of the Douro river in the city of Porto has very little wave action. To my surprise it took place today and was accompanied by the low tide providing a very calm refuge from the open sea. It is still winter in Portugal with heavy gray low cumulus clouds coming from the Atlantic ocean.
Location: Porto, Portugal.

Gear: Nikon D80, ND soft 0.6, a tripod,

Aperture: f/10 Exposure bias: - 0/3 EV
Focal Length: 12 mm
ISO: 100

Date Taken: Wednesday, January 12th, 2011, 16:00