Home / Media / News / NewsSearch
Results:
Tag: alaska
Clear

  • 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.

  • 14-year multipurpose disaster shelter program reaches completion in Bangladesh

    The U.S. Army Corps of Engineers – Alaska District recently completed a robust construction effort aimed at reducing the threat of coastal storms to communities in eastern Bangladesh. Multipurpose Disaster Shelters, or MPDSs, are tailor-made for the volatile conditions of cyclone season. During periods of normal weather, these structures serve functions such as schools and clinics. When the annual storms bring severe flooding, the shelters are built to stand above the flooding and provide secure, elevated spaces for the community.

  • USACE accepting bids for first phase of Port of Nome project construction

    Beginning February 28, 2025, the U.S. Army Corps of Engineers – Alaska District is soliciting contractor bids for the first phase of construction for the Port of Nome Modification Project in Nome, Alaska.

  • Assessing the Validity and Accuracy of Wetland Indicator Status Ratings for Eight Species in Alaska Subregions

    Abstract: Preexisting ecological information and plant species occurrence data were used to determine the accuracy and validity of the present regional and subregional wetland indicator status ratings for eight species: Andromeda polifolia, Arctous rubra, Carex canescens, Rhododendron tomentosum, Rubus arcticus, Salix arctica, Salix pulchra, and Viola palustris. Technical documentation was developed to either (1) support the current National Wetland Plant List (NWPL) subregion boundaries and wetland indicator status ratings for the NWPL Alaska Region or (2) support a proposed change to the subregions or wetland indicator status ratings for the NWPL Alaska Region, for inclusion into the next NWPL update. The project developed repeatable, quantitative methods for assignment of wetland indicator status rating. Analyses included multiple correspondence analysis (MCA), analysis of similarities (ANOSIM), nonmetric multidimensional scaling (NMDS), and principal component analysis (PCA). Prevalence index (PI) was used as a numeric approximation of wetland status for comparing observations across subregions. A pilot study on S. pulchra data evaluated regional assignments by machine learning and assessed the feasibility of correlation network analysis and Louvain clustering for wetland indicator status rating assignment as dictated by co-occurring species. The methods developed for this Alaska-specific study may be applied to any future regional or subregional updates to the NWPL.

  • ERDC researchers discovering hidden caves in Alaska

    The U.S. Army Engineer Research Development Center's (ERDC) Construction Engineering Research Laboratory (CERL) is leading a study alongside the University of Alabama in Huntsville (UAH) and the U.S. Forest Service (USFS) to document cave biodiversity in the TNF and explore how these unique subterranean communities are connected using molecular genetic tools.