I like messing around with that kind of stuff also. My two things would be as mentioned above 1. If you have trees on the stretch, then you'll have very few rat's. I'f you can't cut the trees down then forget it. 2. Food ....In ditches where water celery has gotten thick - the rats will be thick. Cattails, Wapato, Arrowhead, Watercress are all good food choices that you can transplant.