Erosion project set to begin in spring

Due to some extra paperwork, construction on a Sterling Highway erosion mitigation project was delayed to next construction season.
The Alaska Department of Transportation and Public Facilities had planned to begin work at Milepost 153.3 of the Sterling Highway as early as spring 2014, Jill Reese, DOT&PF spokesperson, said in a Clarion interview last November.
Shannon McCarthy, DOT&PF spokesperson, said additional paperwork regarding a separate utility agreement due to electrical lines in the project zone and submitting the project for federal funding pushed the project back.
The department now expects to put the project out for bid this month to begin work in the spring of 2015, McCarthy said. The department initiated the Sterling Highway Erosion Response Project Milepost 150-157 in 2010.
The project involves five construction steps — vegetation removal, soil removal to 8 feet below the original surface, riprap — large rock — placement, embankment construction and revegetation. McCarthy said the department plans to complete the project in the 2015 construction season.
The project is expected to cost just under $5 million; however, the final price tag will depend on bid estimates, she said. State and federal dollars are funding the project, which includes land-purchasing costs.
Groundwater is the culprit in creating the large crater-like feature on the bluff side of the road at Milepost 153.3. The water runs under the highway and down the bluff into the Cook Inlet.
“(The project) should solve the problem because it will allow that water to move down to sea level without bringing the material along with it,” McCarthy said.
The groundwater causes the bluff to erode at a rate of about 1 foot annually. McCarthy said that rate has remained consistent. Last November, Reese said, at the narrowest point between the highway and the edge of the erosion feature about 50 feet of land remained.
McCarthy said DOT&PF is monitoring other areas of this type of groundwater erosion, but no other highways are threatened at this time.