Small streams get a lot less attention from anglers and recreational floaters than medium-size rivers. This makes them a favorable mid-summer destination for fly anglers trying to avoid the crowds.
Small streams like the one above offer solitude to anglers avoiding congested summer canoeing destinations.
In the Rockies, this might mean chasing cutthroats in a meandering creek in a high mountain meadow. In the Smoky Mountains, it could be a shaded canyon with an overgrown creek you could step across. Even many suburban areas have networks of small creeks and drainages we drive by every day that are barely given a thought, despite being loaded with sunfish and bass.
These venues offer unique challenges because of the often tight quarters, and because it can be difficult to approach likely spots and to cast without spooking fish.
Very often these waters are the first place anglers begin to consider lighter lines and shorter length rods. Lighter lines allow you to make more delicate presentations. Shorter rods help in tight spots, and also allow you to load a bit more line on a short cast. The average rod needs 30 feet of line to load, and we're talking much shorter distances here. Ideal brush rods are a little softer for this reason. Some anglers even overload the rod by one line weight so it will load more easily.
Another upside to the "toy tackle" is that smaller fish are more fun on the lighter stuff. Not that you won't occasionally hook a larger fish, and this can become world class sport. Casting shorter rods and developing an awareness of the undergrowth at all times are worthwhile skills to learn, especially since you'll be able to fish water other anglers walk right by.
In all, there is a place in your fly-fishing arsenal for an "ultralight" rig.