what about flooding? is that one.
You were given three really good ideas.
http://www.jiskha.com/display.cgi?id=1223688719.1223688920
strip mining: http://www.google.com/search?q=strip+mining&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
land use: http://findarticles.com/p/articles/mi_hb4801/is_/ai_n17436125 (setting aside land for ATV users so the rest of the land is left undamaged)
oil and gas depletion: http://www.google.com/search?q=oil+and+gas+depletion&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
If you need help learning how to search, including how to choose good search terms, go here and scroll down to the links under HOW TO SEARCH THE INTERNET:
http://hanlib.sou.edu/searchtools/
=)