Dike planned for Utqiagvik will help protect Alaskan arctic town from increasingly extreme storms

The ocean near Utqiagvik was covered in ice last week, but strong winds blew up. Free-running waves can attack the shore and damage homes and roads. They can also eat slowly on land – and with them, cultural sites as well as a sense of security.

“It’s a losing battle,” said Scott Evans, deputy director of capital improvement program management for the Borough of North Slope. “Every day, we get closer to an event that neither of us wants to experience. We’re basically rolling the dice.

A seawall planned for Utqiagvik aims to protect residents from extreme storms while preserving their connection to the ocean.

In November, the North Slope Borough approved an additional $ 300,000 for the US Department of the Army to complete the design of the Barrow Coastal Erosion Mitigation Project. Initial funding of $ 300,000 came in last year.

Engineers have since been making plans for a rock face, taking into account wave behavior, melting ice, and the need for whalers, fishermen and others to access the ocean.

Potential for serious impacts

Severe coastal storms, such as those of 2015 and 2017, are already causing flooding and erosion around Utqiagvik. Evans said last year the ocean surface remained open until November, and with ice forming later each year, strong winds have a longer window to form large coastal waves.

“Our storm seasons are getting longer, the waters are getting freer of ice and our storms are getting more severe,” Evans said. “We all know it’s only a matter of time before we get hit by a big storm.”

The U.S. Army Corps of Engineers assessed coastal erosion and storms at Utqiagvik and outlined key risks in the 2019 Barrow Coastal Erosion Feasibility Study in Alaska.

Strong waves could attack the cliffs at the southern end of town, and houses above it could lose soil below, engineers in the study concluded. Damage to Stevenson Street, which runs along the beach, could cut off residents near the Naval Arctic Research Laboratory.

“If this road happens to erase this road, how can we go back and forth to make sure these people are provided? Evans said.

[From 2015: Barrow’s eroding coastline reveals human bones at Ukkuqsi site]

Residents could lose the city’s only gas station and Alaska’s only tribal college, as well as electricity and internet access, the study found. If the storm waves reach the lagoon area, they could contaminate the community’s only source of fresh water, and “it doesn’t take a single storm for the salt water to actually enter the upper lagoon,” he said. Evans said.

Sewage infrastructure and a former military dump can also be found near the coast, and if damaged, engineers said, the contaminants could harm people as well as birds and marine animals.

Each year, the borough spends approximately $ 8.3 million on emergency response and uses most of the local gravel to obstruct and maintain the temporary berm along the shoreline.

“Our public works workers are actively involved in the storm to repair the berm while the storm is taking place,” Evans said. “If you don’t, (the berm) goes away and you have no protection, so it’s just kind of a big cycle.”

Waiting for a wall

To provide a more permanent solution to the community, engineers recommended raising and lining Stevenson Street and building a two-layered rock liner in the cliff and lagoon area, said Bruce Sexauer, chief of the Department of Civil Engineering Works Management Projects of the Ministry. The wall will extend approximately 5 miles along the coast, from the airport past Browerville to the Naval Arctic Research Facility.

The total cost of the project is estimated at $ 328.6 million. Federal funding will cover 65%, while 35% – about $ 110.5 million – will come from the Borough of North Slope.

The borough pays for the design phase, but the first part of construction funding must come from the federal government. If funding sources like the Infrastructure Investment and Jobs Act push the project forward, engineers could award a construction contract as early as fall 2022, Sexauer said.

“We would start construction as soon as we could,” he said. “It’s kind of a funding limitation right now. “

Construction should start no later than 2025 to ensure the safety of residents, according to the department’s study. Residents are eagerly awaiting the completion of the project, Evans said.

“If something isn’t built, people are going to have to look to move somewhere,” he said.

Maintaining Access

For now, engineers continue to design the first segment of the cladding stretching from the airport, planning the height and composition of the wall.

Over the past decade, engineers have done extensive modeling of the northern Arctic Ocean, examining different storm scenarios from different data points – buoys, weather stations and even ships in the ocean, a explained Sexauer. Now they put that data into a supercomputer to generate wave conditions and see how waves would interact with the shore and move up onto a given structure.

In Utqiagvik, they also have to take into account the rising water levels and the formation of ice later and later each year. The wall should have several layers of rocks of varying sizes to protect the shore and beach from erosion.

The ocean poses a danger to the people of Utqiagvik, but also stores resources such as whales and fish.

“The sea serves as a store for most of our residents,” said Evans. “All of our communities on the North Slope are heavily dependent on subsistence. “

To ensure that the wall preserves access to traditional activities, engineers design the coating with access points such as walkways and openings for boat launches.

“We are working within a community with a strong cultural history – with local tribal entities and whaling captains – to gain a good understanding of the cultural significance of the shore,” Sexauer said. “One thing that is particularly important to them is being able to see and access the shore. “


Source link

Comments are closed.