I am in college getting certified to teach elementary students.  I am
currently taking a class on teaching science to elementary students. 
My professor has assigned us to create a webquest concerning science
and a controversial subject.  She asked me to come up with websites on
the question "Should bulldozers be used to clean out and maintain
creeks?"  She wants us to find at least one website that provides
scientific information with a neutral point of view about whether
bulldozers should be used to clean out creek chanels, at least one
site that provides scientific information that is for using a
bulldozer to clean out a creek channel, and at least one website that
provides scientific information that is against using a bulldozer to
clean out a creek channel.  My professer said it might be hard to find
information on this question.  It certainly has been.  She said if I
couldn't find anything or enough information on that topic I could
find websites for this question "Should dredging be used to clean out
and maintain river channels?"  If that question is used, I would need
at least three websites -- one neutral, one pro, and one con all
providing scientific evidence.  Thank you in advance for your help in
this matter.