Quick action by local citizens can bring results.

There was a fish kill on a tributary of Little Valley Creek.
DEP identifies cause of fish kill
Published: Friday, May 29, 2009
http://www.dailylocal.com/articles/2009/05/29/news/srv0000005445837.txt

For more information about Valley Forge Trout Unlimited go to:
http://www.valleyforgetu.org/index.html

A history of the "saving" Valley Creek can be found in the book by Owen Owens:
Living Waters: How to Save Your Local Stream (Paperback)
by Owen D. Owens (Author)
It is in all the local libraries and local bookshops.
The Amazon listing is here:
http://www.amazon.com/Living-Waters-Save-Local-Stream/dp/0813519985/ref=sid_av_dp