On hills and other sloping roads, rainwater can get up to a good speed as it flows along the gutter at the side of the road, before pouring into the drain. (I estimated it at several litres per second for the gentle hill and heavy shower when this idea came to me.)
Putting a small water wheel inside the drain would allow us to capture some of this energy and put it to good use.
Okay, there's probably not enough energy to make it worthwhile feeding it into the grid, given all the wiring and suchlike that would be required (and the safety issues; water and electricity are not good friends). But we could use it to power something by or in the drain itself...
Now, you may perhaps think of other ways to put this energy to use. What I thought is that the water wheel could wind up a clockwork-powered device that, at night, makes strange and scary noises to make people think there's a monster living in the drain.
(What kind of noises? Gutteral moans.)-- imaginality, Nov 26 2006 Borborygmus
<burp>, oops-- po, Nov 27 2006 Wow, [po], there's a word that deserves to be used more often. My borborygmi are telling me it's time for lunch.-- imaginality, Nov 27 2006 [+]-- webfishrune, Nov 28 2006 Aligator noises of course.-- 2 fries shy of a happy meal, Nov 28 2006 [+] for having caused me to discover the word 'borborygmus' - thankyou [po].-- zen_tom, Nov 28 2006 And I thought [po] made it up! If you say it with an upward intonation at the end, you sound like a tummy rumbling. Guess that's because it's an onomatopoeia. Bun-- jtp, Nov 28 2006 Bunbunygmus +-- squeak, Nov 28 2006 I'd buy it. Then I wouldn't have to keep reminding my girls that the catsnake lives in there.-- nomocrow, Nov 28 2006 sounds good to me-- dev45, Nov 28 2006 Can I nominate [squeak]'s anno for the halfbakery tagline listing?-- shapu, Nov 29 2006 At the pub quiz I went to on Sunday, one of the questions was "What is a borborygmus?"
Knowing that helped us claim second place in the quiz. Cheers [po], I owe you a pint.-- imaginality, Jan 15 2007 Any idea with the suffix "of Terror" is already off to a great start. Nice one [imaginality] and thank 'e [po] for the English lesson, 'tis a great word.-- DocBrown, Jan 15 2007 random, halfbakery