"The larger trout are the ones that survive, that are caught and released, or are never caught," said Hanten. "They are the carryover trout. That is what most of the flyfishermen and ice-fishermen are targeting. They are looking for the larger sized trout. Typically the tailrace food is not limiting. There is always food present. They can put on some pretty impressive growth."

And the conditions are stable enough below the Missouri River dams that anglers can catch these trout during summer, and all the rest of the year.

For the classic trout fishing scene, the Black Hills in western South Dakota provides Western stream and lake fishing that compares favorably with other areas of the West.

During the heat of summer, fishermen typically head for the higher elevations where temperatures are cooler and the trout are in a feeding mood.

The three top streams are Spearfish Creek, Castle Creek and Rapid Creek. In recent years, Rapid Creek has been hit hard by diatoms, a strange growth that attaches to stream beds and rocks, killing insects and limiting fish populations. It's hoped that a phosphorous treatment in Rapid Creek last spring will help alleviate that problem in the future.

Castle Creek and Spearfish Creek haven't been affected yet, at least not in a major way. All of the area through and above Spearfish Canyon has excellent fishing for brown trout in the main stretches, and for brookies in the headwaters.

The best area of Castle Creek lies from Deerfield Dam downstream for a few miles.

"That is a little more difficult to fish, but there are certainly some quality fish in there," said Mark Vickers, with the Black Hills Fly Fishers in Rapid City.

Flyfishermen use 3- to 5-weight fly rods to catch these fish. All kinds of flies are used, with the overall characteristic being that they generally run on the small and sparse side.

"I think the bugs have changed to some extent," said Vickers. The deterioration of Rapid Creek probably has resulted in fewer insects for trout to eat.

"I don't think we have the number of large aquatic insects, stone flies and caddis flies, as we did," said Vickers. "There are some mayflies, Baetis, chironomids, mostly smaller aquatic insects. In my opinion, the number of caddis is well down on Rapid Creek. You used to be able to go out and catch an outrageous number of fish on an elk hair caddis."

When it really gets hot this July and August, beaver ponds are especially attractive. The location of these ponds changes from time to time. Beavers will go into an area and build dams. Then they dine on aspens, birch and other small trees and shrubs. When they have depleted their food, or at least when they have to walk too far to get to it, they will move to a different area.

Generally, the dams are located in the headwaters of streams not only of the main streams, but also many smaller ones as well. These back up enough water to provide homes for lots of brook trout. They grow larger in these ponds because they have plenty of food and a good place to winter.

Stealth is essential when fishing for beaver pond trout. Usually the angler makes an approach from below the dam. The water is often glass still, and quite clear. Typically, you can see the trout swimming about and feeding near the surface. That means the trout also can spot you if you have a high profile. Sometimes you have to crawl up on your hands and knees.

And be especially careful when casting; the fish can be so spooky that they will dart away in terror as the fly line flies overhead, before it even settles down on the water. So, the best conditions are those with a slight breeze that sends a ripple across the water. That helps hide the angler.

Under those conditions, the flies float down on the water near the beaver pond trout. If they are hungry and aggressive, the trout will race each other to pick up your fly. When you hook one, try to make as little commotion as possible when playing and landing it so as not to spook the rest of the fish. As always, these trout are most easily released when caught with barbless hooks.

And in that way you can keep fishing the beaver pond and catching more fish. More than likely, you'll eventually spook the fish. But one of the nice things about beaver ponds is that there seldom is only one. The beavers often make a string of them along a small stream. And so you can continue working your way from one pond to another and catch trout from each pool.

All of this angling takes place within the pines and aspens of the mountains in the Dakotas, where even the July heat can't stop the good trout fishing.

Find more about Great Plains fishing and hunting at: GreatPlainsGameandFish.com