Near Belchertown, the Swift River is a popular tailwater fly fishery. The best section is below Quabbin Reservoir (Windsor Dam) to SR9. This stretch is an excellent catch-and-release zone for fly fishing only. The cold tailwater make for outstanding year-round fishing. There are plenty of stocked rainbow trout and brown trout, typically around 16 inches long. The lower section downstream of SR9 is known for its flat pools connected by shallow riffles. This section runs down to Cady Lane and is a catch-and-release stretch from July to December (check current schedule). It is pretty tight winding through the forest and can be difficult for casting.
To access the section below the dam, start walking from the Quabbin Reservoir main gate or walk up from the SR9 bridge. The lower section can also be accessed by walking from the SR9 bridge.