In round numbers Iowa has 80 trout streams that total some 260 miles, with the best angling found on about twenty streams that total 60 miles. In other words, the streams are in the Mississippi River basin bluff country. Iowa's showcase stream is a tiny spring creek named Spring Branch Creek that flows through the grounds of the hatchery at Manchester, on U. S. Route 20. This stream is gaining popularity with Illinois anglers because is is relatively accessible to Chicagoland. It gets crowded, but there are usually enough fish to go around.
Weekdays are best, of course.
Many Iowa streams have water cress, making scuds very useful, while streamers may be best to hook the largest fish. A few of us enjoy using traditional wet flies a la Ray Bergman and Helen Shaw.