I'm looking at buying a piece of land near some agricultural land and building a nice pond with largemouth bass, etc. I would not be able to control runoff in to the pond, so I'm wondering how concerned I should be about fertilizers, herbicides running into my pond. I assume it has to do with how far the ag land is from my pond, so can someone tell me how far away is far enough, etc? There actually is an existing 1 acre pond on the land that I want to enlarge.

Thanks