If you see stock in waterways, or evidence of polution from animal effluent, or wasteful use of water, don't hesitate to write to ECan, pointing out the problem. So much the better if you can include some photos.
Address your letter to:
Customer Services
Environment Canterbury
PO Box 345
Christchurch,
and preferably with a copy to your ECan politician at the same address.
or free phone ECAN: 0800 76 55 88