Residents of Juneau, Alaska, faced another round of flooding this year from the Mendenhall Glacier, a problem that has become an annual challenge. Fortunately, a large temporary wall of reinforced sandbags helped keep the worst of the floodwaters at bay, a relief compared to the severe damage seen in recent years.
The flooding happens because of water trapped behind an ice dam at the glacier. Each spring and summer, rain and melting snow fill a nearby depression called Suicide Basin. When enough water builds up, it breaks through or goes around the ice dam and floods down the Mendenhall River, threatening homes along the way. This has been happening yearly since 2011 and has grown worse over time, with more record-high water levels in the last three years.
This year, city officials worked with state, federal, and tribal groups to put in place around 10,000 “Hesco” barriers—giant sandbags designed to protect about 460 homes over 2.5 miles of riverbank. Homeowners in the flood zone had to pay part of the cost, roughly $6,300 each over 10 years, with some asked to contribute extra for riverbank reinforcement. Though some residents voiced objections, the project moved forward.
Though the barriers held back much of the water, some seepage still occurred. Officials called the project a success but warned that more work is needed to strengthen and extend the protection.
The flood threat is tied to climate change. As glaciers melt and shrink, lakes like Suicide Basin form and fill with water. Scientists expect that in the coming decades, the Mendenhall Glacier may retreat enough to stop acting as a dam. But new lakes could form and cause similar floods elsewhere.
Finding a long-lasting fix is tough because so much is still unknown. The Army Corps of Engineers has nearly $5 million set aside to study the problem and start planning a permanent solution. As Brig. Gen. Clete Goetz said, seeing the flood risk is easy; figuring out the right answer is the hard part.
For now, the sandbag barrier will have to hold for up to 10 years while experts study the changing glacier and its effects. Juneau’s residents hope a safer, more permanent way to protect their homes will come soon – because they cannot keep facing this emergency year after year.