We are on a 50-passenger jet boat up the Class VI rapids of Devil’s Canyon on the Susitna River in Alaska. Ahead of us is a 10-foot high waterfall at one of the narrowest points yet in the canyon. It’s loud. The roar of the jet boat is lost in the thrumming as the reddish-brown canyon walls squeeze one of the largest rivers on the continent and drop it off that ledge. Most conversation has stopped and we are all wondering, hoping, that the boat is going to stop here.
We were free to move about the boat until we reached Devil’s Canyon. Then the captain asked us to stay seated until we reached the turn-around point. We began rocking and rolling up the river as the canyon walls rose and closed around us. Then we reached this waterfall. The captain does stop and somehow he keeps the boat hovering at the bottom of that drop for more than half an hour. Once we realize that he really can hold the boat at the bottom of the waterfall, we take turns snapping photos at the front of the boat, laughing at the sheer power of the water.
The Susitna River of Devil’s Canyon is nothing like the river I know. The rapids are the out-of-control, high-energy teenager that eventually becomes the driven yet patient mother whose sharp, angular features have become soft and rounded with time.
Most of my experience of the Susitna has been on that matriarchal river – a mile-wide braided stretch more than 50 miles south of Devil’s Canyon. My small town sits near the confluence of three rivers – the Susitna, Chulitna, and Talkeetna – and is named after the last one.
Friends have an annual tradition of marking the end of the school year with a lazy overnight float from Talkeetna. We pull the rafts out at a large island in the middle of the Susitna to be safer from bears, set up tents, and play games like bocce ball and croquet on the sand-and-cobble beach. One year we watched a moose cow swim across the river to a nearby island to find that same haven from bears. We cheered on her reddish newborn calf, still wobbly on land, as it struggled against the current, slipping far downstream of its mother.
I live a few miles south of town on a bluff above the wide plain where the Susitna has meandered over millennia. We fish nearby where a large creek flows into a slow-moving side slough of the river, milky with glacial silt. Salmon emerge from the slough’s murkiness into the creek’s clear waters. Some will spawn in the slough while others continue upstream to spawn in the creek or the lakes and ponds connected to it.
The Susitna valley, larger than nine individual states, supports diverse life. Salmon may be the richest gift offered – millions of pink, chum, Chinook, sockeye, and coho swim up its powerful current each summer to reach their spawning grounds. These salmon feed the eagles, the bears, and the Alaskans who fish to fill their own freezers or America’s grills. Sockeye fillets at fish counters across the country may be from Susitna stocks that were harvested in Cook Inlet, one of Alaska’s sustainably managed fisheries, on their way back to the river and the trail to their natal grounds.
I didn’t realize how mighty these Susitna salmon could be until I went on that jet boat tour. Chinook salmon fight their way over that 10-foot waterfall to spawn in the large creeks above the canyon. I’ve always been impressed with the distances that salmon migrate to spawn, up to 1,980 miles on the Yukon River, and I’ve seen the small waterfalls that they navigate on other rivers, like Brooks Falls on the Brooks River in Alaska’s Bristol Bay. But I’d never imagined that they could pass through a gauntlet like Devil’s Canyon.
More than once, the state of Alaska has proposed to build a dam about 30 miles above Devil’s Canyon that the Chinook won’t be able to fight their way over. The 735-foot tall Susitna-Watana Dam would not only block salmon migration, its operation could change flows below the dam so drastically that river level would be flip-flopped from the natural high summer flows and low, frozen winter conditions, and sloughs where the sockeye migrate and spawn could dry up before the fish arrive.
The Susitna is one of the last free-flowing rivers in the U.S. Other than being flanked by the railroad tracks for part of its length and crossed by three bridges, our towns and highways have made few changes to the Susitna on its 313-mile journey from glacier to ocean. It’s rare these days for such a large river – 15th largest by volume in the country – not to be molded in some way, at some place, to the needs and will of people.
This is why the Conservancy’s science has assessed the risk that a mega-dam would pose to the natural flow of the river. We want to understand how altering those flows affects the ability of the Susitna – and similar braided rivers – to create all the nooks and crannies that the salmon depend upon to live out their lives and create more salmon.
That’s not to say we’re not asking anything of this river – its wild salmon are an economic mainstay for Alaska. And as long as we don’t interfere, it’s likely to continue doing what it does best, all on its own.
Corinne Smith manages the Matanuska-Susitna Basin program for The Nature Conservancy in Alaska.