Trails to a series of vividly green pools begin near the Zion Lodge Shuttle Stop and run uphill through Heap’s Canyon. The pools are created by water from the same spring that carved the canyon, and colored by algae. The trail to the lower and middle pools is paved, but the path connecting the middle and upper pools is rough, sandy, and mostly uphill.You can customize your hike on the Emerald Pools Trail based on distance and difficulty: just decide whether you want to take the easy hike to the lower pools or the moderately difficult trek to the middle or upper pools. It will take you about an hour roundtrip to hike to the Lower Pools and about twice that if you go all the way to the Upper Pools.