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  • USACE seeks public comment on draft Homer Harbor study

    The U.S. Army Corps of Engineers – Alaska District prepared a new feasibility study and environmental assessment for navigational improvements at Homer Harbor and is seeking public comment on the draft document.

  • Sec. Telle outlines Corps’ flood mitigation efforts for Mendenhall Glacier

    The Assistant Secretary of the Army for Civil Works, Adam Telle, visited Juneau last week to observe the US Army Corps of Engineers (USACE) ongoing solutions to address flooding ahead of the annual Mendenhall Glacier Outburst Flooding Events, also known as GLOFs.

  • Complete Genomic Sequences of Nine Bacillota Isolated from Alaskan Permafrost

    Abstract: A total of nine Bacillota bacteria were isolated from Alaskan permafrost, and complete genomic sequences were obtained via hybrid assembly of long and short reads (Oxford Nanopore and Illumina paired-end sequencing, respectively). These genomes highlight the diversity of Arctic Bacillota and their potential applications in biotechnology.

  • Army Research Aims to Standardize Arctic Winter Road Construction

    A recent report from the U.S Army Engineer Research and Development Center’s Cold Regions Research and Engineering Laboratory (CRREL) is providing crucial guidance on building and maintaining the vital, yet unpredictable, winter roads in challenging northern environments.

  • U.S. Army Corps of Engineers to host public meetings for former SM-1A nuclear power plant

    The U.S. Army Corps of Engineers, Baltimore District, will host a series of in-person and virtual public meetings to update and share information on the SM-1A Deactivated Nuclear Power Plant Decommissioning and Dismantlement project at Fort Greely, Alaska.

  • Snow Depth Measurements from Arctic Tundra and Boreal Forest Collected During NASA SnowEx Alaska Campaign

    Abstract: Boreal forest and Arctic tundra environments collectively hold the largest percentage of global terrestrial seasonal snow cover. Тhe in-situ snow measurement network is sparse and costly in these remote northern regions. Here, we complement existing snow depth monitoring in Arctic tundra and boreal forest by presenting an extensive (64°N–70°N) snow depth dataset and description of ground-based snow depth measurements collected during the NASA SnowEx Alaska intensive field campaign, March 7–16, 2023. We also report the accuracy of snow depth measurements in shallow boreal forest and Arctic tundra snowpack and share considerations in developing the consistent and repeatable snow depth data collection procedures. Snow depth measurements and technical validation described in this paper can serve as a robust product for testing snow remote sensing techniques, and for providing a reference dataset for climatological and hydrological studies.

  • Mapping the Vulnerability of Boreal Permafrost in Central Alaska in Relation to Thaw Rate, Ground Ice, and Thermokarst Development

    Abstract: Permafrost roughly affects half the boreal region in Alaska and varies greatly in its thermophysical properties and genesis. In boreal ecosystems, permafrost formation and degradation respond to complex interactions among climate, topography, hydrology, soils, vegetation, and disturbance. We synthesized data on soil thermal conditions and permafrost characteristics to assess current permafrost conditions in central Alaska, and classified and mapped soil landscapes vulnerable to future thaw and thermokarst development. Permafrost soil properties at 160 sites ranged from rocky soils in hillslope colluvium and glacial till, to silty loess, to thick peats on abandoned floodplains and bogs, across 64 geomorphic units. To assess the vulnerability of permafrost to climate variability and disturbance, we differentiated permafrost responses in terms of rate of thaw, potential thaw settlement, and thermokarst development. Using a rule-based model that uses geomorphic units for spatial extrapolation at the landscape scale, we mapped 10 vulnerability classes across three areas ranging from high potential settlement/low thaw rate in extremely ice-rich loess to low potential settlement/high thaw rate in rocky hillslope colluvium. Vulnerability classes corresponded to thermokarst features developed in response to past climates. Differing patterns in permafrost vulnerability have large implications for ecosystem trajectories, land use, and infrastructure damage from thaw.

  • Active Layer and Permafrost Microbial Community Coalescence Increases Soil Activity and Diversity in Mixed Communities Compared to Permafrost Alone

    Abstract: Permafrost is experiencing rapid degradation due to climate warming. Dispersal of microbial communities from the seasonally-thawed active layer soil into newly thawed permafrost may influence community assembly and increase carbon release from soils. We conducted a laboratory soil mixing study to understand how carbon utilization, heterotrophic respiration, and microbial community structure were affected when active layer and permafrost soils were mixed in varying proportions. Active layer soil and permafrost collected from two sites in Alaska were mixed in five different ratios and incubated for 100 days at 10°C. Respiration rates were highest in the 100% active layer soils, averaging 19.8 µg C-CO2 g−1 dry soil d−1 across both sites, and decreased linearly as the ratio of permafrost increased. Mixing of the two soil layers resulted in utilization of a more diverse group of carbon substrates compared to permafrost alone. Additionally, combining active layer and permafrost soils increased microbial diversity and resulted in communities resembling those from the active layer when soils were mixed in equal ratios. Understanding the effects of active layer-permafrost mixing on functional potential and soil organic matter decomposition will improve predictions of carbon-climate feedbacks as permafrost thaws in these regions.

  • Temporary flood barriers prove effective during flood event in Juneau

    During the week of August 11, the Mendenhall Glacier released its yearly glacier lake outburst flood, also known as a jökulhlaup (Yah-cuh-laup). In preparation for the potential threat to infrastructure and public safety, the U.S. Army Corps of Engineers provided temporary flood mitigation barriers to the City and Borough of Juneau last winter. While USACE continues to prepare a technical study that will help to define the parameters of an enduring flood risk mitigation solution, these barriers provided vital short-term protection to the community along the river this week by holding back the glacial water released from Suicide Basin and performing well during the peak of the floodwaters.

  • USACE breaks ground at coastal erosion project in Alaskan community of Utqiagvik

    Representatives of the U.S. Army Corps of Engineers - Alaska District participated in the groundbreaking ceremony for the Barrow Coastal Erosion Project in the community of Utqiagvik on Aug. 11. They joined representatives of the North Slope Borough and the contractor to celebrate the construction of the critical shoreline protection, which began in July after the first batch of armor rock arrived from Nome on the 28th.