Zep

What a scenario - essentially free irrigation! That's amazing...good for you - and congrats on the new land acquisition.

Two sides to this in my mind: Former owner has already been pumping the lake water into the pond - any damage in the form of invasive species or water chemistry/quality, vegetation issues has been introduced, and the pond/fishery has adapted. Bottom line - the BOW has already been introduced to any negative effects so you're OK moving forward with future irrigation.

Second side says be very cautious to continue. Get to know the BOW from which you're pumping. Understand you could be introducing any/all vegetation cultivars and fish species present there into your BOW. Are you willing/prepared to respond to any negative effects?

One immediate solution might be to pump the irrigation water do a small holding wetland area away from your pond. You could have that water slowly seep through another wetland area to eventually irrigate your pond. The wetland would ideally absorb any excess nutrients or clear turbid water and if you boxscreened the irrigation pipe outlet you could theoretically prevent any invasive fish species from entering your fishery.

Just my immediate feedback on the situation. Will look forward to other takes on this situation.

Many men go fishing all of their lives without knowing that it is not fish they are after. ~ Henry David Thoreau

[Linked Image from i1261.photobucket.com]