Eddie,
Give it a few months to stabilize...but keep an eye out for any wet areas behind the dam.
A comment on your stocking plan...the F1 LMB is a great choice for growing large catchable predators. Your supplier has some great genetics in both the LMB and CNBG. As far as stocking Tilapia are concerned this first year, my opinion is that it depends on the size of the stocker LMB and also on the water quality...i.e. if the LMB are stocked at 4 to 6 inches, they will feast on small Tilapia offspring all through the growing season and you will get algae control as a bonus. If you aren't concerned about algae and/or stock LMB smaller than 4 inches, then Tilapia won't do much for you. Otherwise, this first year, I'd stock them, in small numbers, for the algae control and for the forage they will provide your LMB.