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12.09.2019 | Earth Intelligence

Road versus river: infrastructure maintenance in Alaska’s Copper River Delta

By: Caitlin Frye, Northern Region Information Officer, Alaska Department of Transportation & Public Facilities

Read Time: 5 minutes

You may not know much about the Copper River, but you have almost certainly heard of the famous Copper River salmon. If you’re lucky enough to have tasted one, you may have an inkling why the wild 584 square-mile Copper River Delta is one of the most important bodies of water in Alaska—important to our economy, our subsistence, our wildlife, our environment and even our very identity. You may not have thought, however, about the road that crosses it—or, used to cross it.

In the early 1900s, a fortune in unmined copper motivated the construction of a rail route from the deep water port in Cordova across the massive Copper River Delta to the Kennicott mines. By 1945, this then-abandoned rail route was the logical place to start construction of a road from Cordova to the Richardson Highway, connecting the isolated fishing community to the American highway system. Construction lasted for decades until the 1964 earthquake collapsed the northern span of the historic Million Dollar Bridge south of Kennicott and construction halted.

The Miles Glacier Bridge, also known as the Million Dollar Bridge, across the Copper River.

Construction never restarted to complete the road connection to Cordova, but the Copper River Highway nonetheless became an important road for tourists, business owners, scientists, hunters, fishermen and adventurers looking to explore Alaska’s vast wilderness and resources. The Alaska Department of Transportation & Public Facilities (DOT&PF), which now maintains the scenic route, even finished permanent repairs to restore the Million Dollar Bridge in 2005 (seen above in the summer of 2019).

This drone image from the summer of 2019 shows how the Copper River has wiped out all land and the road between bridge 339 and the bridge after it, leading drivers to be ferried across the river to reach the opposite side of the road.

But maintaining this road is no average feat. One defining characteristic of a great, undammed river delta is that it moves. As you can see from the Maxar imagery over time (below), the braids of the river shift and eat whatever land (or road) is unlucky enough to be in its path. The first washout happened at bridge 339, a little more than 30 miles outside Cordova. The river eroded the approaches and scoured the supports, making the bridge impassable in 2011. As the river continued to change course, it completely washed away all of the 1,500 feet of land and road between the now-impassable bridge 339 and the bridge after it. The road was no longer drivable after mile 36 and the cost to maintain it was becoming increasingly unmanageable.

In these images, Bridge 339 is on the left side. The before image (left) was taken by Maxar’s WorldView-2 satellite on Oct. 28, 2011. Maxar’s GeoEye-1 satellite captured the after image (right) of the land washing away on June 29, 2019.

After these washouts, road users began shuttling across the river in boats to access the other side, underscoring the importance of this infrastructure to Alaska and its visitors. As the road continued to be used and valued by the public, DOT&PF staff watched Maxar satellite imagery to track the changing river. The Northern Region office of DOT&PF, which maintains the Copper River Highway, monitors and maintains infrastructure in about 370,000 square miles of Alaskan territory. Maxar’s high-resolution satellite imagery allows us to keep an eye on remote areas and determine when and what kind of assistance is needed. In this instance, the Copper River Delta is more than 300 miles from DOT&PF’s office in Fairbanks and requires five hours of travel time via plane (with layovers) to reach this location; it would be impractical to routinely monitor this infrastructure in person.

Alaska DOT&PF responsibilities are split between three regions. The Copper River Delta is part of the Northern Region, which is larger than the state of Texas.

In 2018, high waters washed out another 1,000 feet of road beyond the impassable bridge, and this time, maintenance staff couldn’t drive heavy equipment to the site to fix it. Even the Million Dollar Bridge, repaired in 2005, can’t seem to hold its own against the mighty river. The Miles Glacier, just upstream, is calving icebergs that slam into concrete ice-breakers set up in front of the bridge’s piers to protect them. The ice-breakers are failing and bridge design staff are left with the question of what to do?

Preserving and maintaining Alaska’s remote infrastructure is one of the most difficult challenges we face at DOT&PF. In the case of the Copper River Highway, balancing the needs of a small, but important community of residents, scientists and business-owners with the engineering, environmental and cost challenges of keeping the road open is something we continue to grapple with. The next time you’re eating one of our famous salmon, you’ll know that before it ended up on your plate, it swam right past our washed out road and our engineers’ dilemma.

Alaska DOT&PF Northern Region Preconstruction Engineer, Sarah Schacher, P.E., showing off the efforts of her Copper River Salmon fishing.

Header image courtesy ESA’s Copernicus Sentinel-2 satellite from Sept. 26, 2019.

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