The Green Trail in the upper Blackwater River can be accessed at the refuge's soft launch on Route 335 at the Blackwater River Bridge. Here, the marsh ranges from slightly brackish to fresh water. During summer, fragrant waterlily covers much of the water and narrow-leaved cattail grows at the water's edge. This trail is 4 miles one way. Water trails are open daily, dawn to dusk.

Going 2-3 miles per hour, this trail will take 2.6 to 4 hours.