Justin Harding of Utah Pro Fly Fishing and I spent a couple of hours one evening fishing the small stream that comes out of Smithfield canyon. To our surprise the stream holds and produces rainbow trout. While the size of the trout we caught were not the biggest there have been reports of up to 12 inches. It would be recommended to fish with a 2 weight rod if one were going to try to fly fish this stream. The easiest access is below and above the dam just east of Mack Park. A couple of my friends have fished it all the way up the canyon and said that they have caught dozens of fish. Keep in mind that the stream is very over-grown in most places. One of my friends even used an ice fishing pole to access it better.