Brooktrout are you going to have to pump water or will the pond be lower than the stream?
Also I would dig the pond as deep as you can afford taking into account the type of soil you have, and get someone who is experienced at building ponds.
A good aerator system is always a plus especially with trout but beware turning over too much water during hot months.
My pond is fed from a stream that is higher than the pond and a 2 inch pipe supplies about 60 GPM with a head of 12 ft., total from 2 pipes is about 110 gpm and the trout survive fine with a max pond depth of 8ft., but then my summers are probably cooler than yours.
