Hi, Brian --
There is a lot of good information on this site about trout pond management -- and ponds with springs.
I have a small (less than 1/4 acre) spring-fed pond down in Virginia. I think Dave in el dorado has you pointed in the right direction. Maybe Cecil will weigh in, too -- he's quite an expert at raising trout in ponds.
From what I've learned on this site (and through some trial and error), you probably don't want to back water up over your springs; rather, let the spring water flow down into the ponds. Aeration is also very beneficial -- in the case of my little pond, it is absolutely essential. I run it 24/7 all the time, except for the very coldest part of winter (my pond never ices over completely).
What is the flow rate of your springs? Mine runs at an average of about 35 gallons per minute, or 50,000 gallons per day. That's a little on the puny side, but it gets the job done. Since you're farther north, and have somewhat cooler summers, you may be able to get by with less spring flow. Elevation is important, too. I recall seeing an old USDA publication years ago (I'm an old guy) entitled "Trout in Farm and Ranch Ponds." It featured a great map showing contour elevations of the US, with a minimum elevation number indicating _probable_ success of a trout pond. The elevation number for my part of Virginia was 1,500' above sea level. My hunch it could be as low as 1,200' or even 1,000' above sea level for Pennsylvania.
I think rainbows are great pond fish. They respond well to pelleted feed -- but also use the natural food supply in ponds. The ones in my pond love midges and damsel fly nymphs -- and this time of year, they really love grasshoppers that wind up in the pond.
If I had it to do all over again, I would remove all the warmwater species that were in my pond when I got this place. My bass are all pretty small -- almost never exceeding 15" in length. But even at that size, they are very effective predators on small stocked trout ... I lost 40 6"-8" brookies last winter to a handful of hungry (and now very plump) largemouths. The trout seem to co-exist okay with my hyrid sunfish. One side benefit of my feeding program is that many hybrid sunnies are now avid pellet feeders as well -- which really helps them put on the weight. As fly rod fish, they are every bit the equal to the rainbows, in my humble opinion.
I wish I could address the HSB issue, but it's a species I am just not familiar with.
So, to sum up, here's my best counsel: try to get your springs to flow down into your ponds; be sure to explore the benefits of aeration; and try to keep the list of species stocked (along with trout) pretty short.
One more thought: you don't read too much about it, but there are various races and strains of hatchery rainbows available. Some tolerate pond conditions better than others. The two private hatcheries where I purchase my trout here in western Virginia use strains that are well-suited for this climate. I've just marked my fifth summer of having trout survive Virginia summers in my pond -- credit goes to a puny spring, a big aerator, good strains of rainbows, and, above all, to PONDBOSS. The magazine and this site have bailed me out of self-inflicted pond management woes many a time!
Good luck and keep us all up to date on how your pond project progresses.
-- Mike Smith, Lexington, VA
