Black Canyon: Willow Beach to Emerald Cave

Launch at Willow Beach, the marina on the Arizona side of the Colorado River about 11 river miles below Hoover Dam, and paddle upstream into Black Canyon, on the Black Canyon National Water Trail. Dark volcanic walls rise straight from the water, and bighorn sheep are often seen on the ledges. Keep to the edges and the eddies, out of the main current, for 2 miles to Emerald Cave, a small grotto in the canyon wall; reverse in, and if the sun is on the water the whole cave glows green. Come back down with the current.

It is 4.2 miles (6.7 km) there and back, close to the Park Service's 2 miles each way; allow about 1½ hours in a canoe or kayak and 2 on a paddleboard, though the upstream leg takes longer when the dam is releasing hard. The grade is Moderate: the river is usually calm here, but the current changes with releases from Hoover Dam, the water stays in the low 50s°F all year, and summer heat is extreme.

Here everyone must wear a Coast Guard-approved life jacket while under way. You need a park pass, but there is no launch fee for paddlecraft. Lake Mohave has quagga mussels: Nevada requires an invasive species decal on canoes and kayaks, and every boat must be cleaned, drained and dried. Motorboats are banned upstream of Willow Beach on Sundays and Mondays. Wear a life jacket and check the conditions before you set off.

Route drawn by Global Adventurer along OpenStreetMap waterways (© OpenStreetMap contributors, ODbL), with figures worked out from it. Check the forecast and the ground on the day: paths change.