English: Rafting through The Gates of Aniakchak, Aniakchak National Monument & Preserve (U.S. National Park Service). Congress named the Aniakchak a national wild river in 1980. Its spectacular resources make rafting the Aniakchak a most rewarding experience. You can float from inside a volcano to the ocean, past spectacles of wildlife and geology. From Surprise Lake, the river flows a peaceful mile to The Gates. The river moves swiftly through this narrow gorge in the caldera wall, and large rocks demand precise maneuvering. A gradient of 75 feet per mile makes this section challenging. After a more gentle 10 miles comes the confluence with Hidden Creek, and the river is again filled with car-sized boulders, abrupt bends, and a narrow bed requiring extreme caution. After 5 more miles, the river slows to meander toward the Pacific Ocean and the seals, sea otters, bald eagles, and sea birds of Aniakchak Bay (NPS).