Trail: Middle Emerald Pools Trailhead: Zion Canyon Scenic Drive- opposite Zion Lodge Round Trip: 2.0 miles/3.3 kilometers 2 hours. Ascent: 150 feet/46 meters Description: Moderate. Long drop-offs. Loop trail to lower and middle pools. NOTE: Swimming, wading or bathing is prohibited in all pools, in order to protect the aquatic wildlife and preserve this fragile area.