I watched a spawning creek, home to three species of salmon, die. 
The once active salmon spawning creek, that had flourished for as far back in living memory goes, 80 + years, runs through my property. 
I was eye witness to the effects of the damage caused by people clueless about soil erosion caused by cutting down trees next to the creek and mistakes made by DOT that altered water flow, which compounded the problem of the aged culvert, causing flooding.  
It was listed for replacement for over 15 years ago by A.F.&G. The culvert was finally finished off by a large tour vehicle that ran off the road and hung over the creek, causing the culvert to break off, making it impossible for the fish to pass. 
The state salmon habitat man tried to help get the culvert replaced and has faithfully documented the progression of damage. 
It's ironic, that my State House Rep. is the Chair of the House Fish and Game finance, has failed to follow through to get the culvert replaced and damage fixed.