Posted by Charles on August 29, 2003 at 19:36:13 from 81.152.79.43 user Charles_Coull.
In Reply to: Re: milk in tea, and drinking lake water posted by Mike Dennis on August 29, 2003 at 15:19:50:
When going to the source of the stream you're going upstream.
There is a theory that the further downstream you get from any pollution the more chance that the action of the stream has had to dissipate the pollutant (I'm sure someone else has a better explanation of this).
So if there is a dead sheep round the bend from you upstream and you walk 50 yds downstream from it then the stream will have had some time to do its self cleaning thing.