funnel-like concrete tube that leads to a tunnel under the earthen dam and prevents high flows from overtopping the dam. The last dam built on the Deerfield was Fife Brook Dam, which was built in the early 1970s in conjunction with the development of the Bear Swamp Pumped Storage facility. This facility acts as a battery for power generated during times of low demand. By using excess electricity to pump water to the top of the mountain, where a reservoir was created by building levees around an existing high swamp, energy is stored. When electrical demand is higher (usually midday or afternoon/evening) the water from the upper reservoir can be released through the turbines (which act as pumps in reverse) to meet demand. The third commercial nuclear reactor in the United States was built in the town of Rowe, Massachusetts, on the banks of the Deerfield River by Sherman Reservoir. Known as "Yankee Rowe", it generated electricity for New England from 1960 to 1992. The eastern entrance of the Hoosac Tunnel is located on the river in the town of Florida, Massachusetts. It is a railroad tunnel, still in use, started in 1851 and completed in 1875. The Burleigh Rock Drill, one of the first pneumatic drills, was used in its construction. Construction also featured the first large-scale commercial use of nitroglycerine and electric blasting caps. The American Society of Civil Engineers made the tunnel a Historic Civil Engineering Landmark in 1975. The Bardwell's Ferry Bridge is a pin-connected through truss, built in 1882 and spanning the Deerfield River between the towns of Shelburne and Conway in Franklin County. It is the longest single-span lenticular bridge in Massachusetts. It has been listed on the National Register of Historic Places. Recreation Activities on and around the Deerfield include whitewater kayaking, canoeing, tubing, fishing, swimming, and camping. A popular swimming area by the Stillwater Bridge in Deerfield has waterside cliffs up to forty feet high that swimmers jump from; this activity is tolerated but not condoned. There are two sections of the river for whitewater paddling: the Fife Brook section for class II and III paddlers, and the "Dryway" for class IV paddlers. There are several tributaries of the Deerfield River that provide excellent whitewater creek runs, including the class IV-V West Branch of the Deerfield in Readsboro, Vermont, the class V Dunbar Brook in Monroe, Massachusetts, the class V Pelham Brook