I was walking along a canal several days ago, and, the UK weather being what it is at the moment, the canal was frozen. However under all the bridges that crossed the canal, whether footbridge or road bridge, the water was unfrozen. What is it about the bridges that stops the water under them from freezing?

OK, so this question is not directly about science, but is related to science and scientists.

For the last couple of years I have been walking over Harvard bridge from Boston to Cambridge. The bridge is marked in Smoots - recalling a famous 1958 1958 MIT fraternity prank where Oliver Smoot (at 5 feet and 7 inches) was used as a unit to measure the bridge. The bridge was found out to measure 364.4 Smoots (plus or minus one ear). You can read all about Smoots here:

http://en.wikipedia.org/wiki/Smoot

The pledge class of Lambda Chi Alpha are supposed to re-paint the Smoot markings on the bridge regularly, but I have noticed that on the East side of the bridge that the signs are very faded, many of them so much so that they are unreadable. Over the last year or so the signs have not been repainted at all.

Does anyone have any idea why the signs have not been repainted. Has the recession hit the frat guys and prevented them from investing in paint? Have they just given up? Or have I missed something?

(also here is random picture of a friend on the bridge)