One thing I have both read about and noticed from personal observation is how easy it is for tiny fish to swim upstream or get flushed downstream in the shallowest of water during big rain events. I have seen inch long BG swimming around in inch deep water overflowing from my pre-sediment pond to my sediment pond. I've seen hundreds of small fish flow out my emergency overflow in the big pond during a big rain event.
One concern I have with this new pond is that my old pond is adjacent to it only maybe 150 feet south and share the same water shed. The old pond has both GSF and BH, neither of which I want in this pond and either of which would totally screw up my plans. Especially if they got in the pond early before the RES are established. Not quite as big of deal if it happened a few years down the road when the RES had filled the pond to capacity. But it would definitely change my need for having a predator fish in the pond.
With that in mind I ran a diversion finger or type of terrace up the hill a couple feed in elevation. It should divide the water far enough up the hill that only the very largest of rains might provide deep enough water for fish to swim up and get around the finger. I suspect some day they will, but I hope to put that day off as long as possible.
Pictures below of the ponds proximity and the diversion finger extending into the field.
Edit: Now that I write this post and think about the problems BH and GSF would cause for my "plan", I think I will get on the dozer this morning and extend a double channel terrace a lot further out into the field. Better safe than sorry.
