Three members of Vermont’s congressional delegation are hoping to add the Upper Missisquoi and Trout rivers in the northern part of the state to the National Wild and Scenic Rivers System. Senators Patrick Leahy and Bernie Sanders and US Representative Peter Welch introduced legislation Thursday to add the Vermont rivers to the system, which is managed by the US Department of the Interior. Currently 40 other states have rivers listed under the system, created in 1968 to recognize and preserve rivers with scenic and recreational value.