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  • Evaluation of Geocell-Reinforced Backfill for Airfield Pavement Repair

    Abstract: After an airfield has been attacked, temporary airfield pavement repairs should be accomplished quickly to restore flight operations. Often, the repairs are made with inadequate materials and insufficient manpower due to limited available resources. Legacy airfield damage repair (ADR) methods for repairing bomb damage consist of using bomb damage debris to fill the crater, followed by placement of crushed stone or rapid-setting flowable fill backfill with a foreign object debris (FOD) cover. While these backfill methods have provided successful results, they are heavily dependent on specific material and equipment resources that are not always readily available. Under emergency conditions, it is desirable to reduce the logistical burden while providing a suitable repair, especially in areas with weak subgrades. Geocells are cellular confinement systems of interconnected cells that can be used to reinforce geotechnical materials. The primary benefit of geocells is that lower quality backfill materials can be used instead of crushed stone to provide a temporary repair. This report summarizes a series of laboratory and field experiments performed to evaluate different geocell materials and geometries in combinations with a variety of soils to verify their effectiveness at supporting heavy aircraft loads. Results provide specific recommendations for using geocell technology for backfill reinforcement for emergency airfield repairs.

  • Semi-Automated Land Cover Mapping Using an Ensemble of Support Vector Machines with Moderate Resolution Imagery Integrated into a Custom Decision Support Tool

    Abstract: Land cover type is a fundamental remote sensing-derived variable for terrain analysis and environmental mapping applications. The currently available products are produced only for a single season or a specific year. Some of these products have a coarse resolution and quickly become outdated, as land cover type can undergo significant change over a short time period. In order to enable on-demand generation of timely and accurate land cover type products, we developed a sensor-agnostic framework leveraging pre-trained machine learning models. We also generated land cover models for Sentinel-2 (20m) and Landsat 8 imagery (30m) using either a single date of imagery or two dates of imagery for mapping land cover type. The two-date model includes 11 land cover type classes, whereas the single-date model contains 6 classes. The models’ overall accuracies were 84% (Sentinel-2 single date), 82% (Sentinel-2 two date), and 86% (Landsat 8 two date) across the continental United States. The three different models were built into an ArcGIS Pro Python toolbox to enable a semi-automated workflow for end users to generate their own land cover type maps on demand. The toolboxes were built using parallel processing and image-splitting techniques to enable faster computation and for use on less-powerful machines.

  • Field Jet Erosion Tests on Benbrook Dam, Texas

    Abstract: This report summarizes the results of eight field Jet Erosion Tests (JETs) performed on Benbrook Dam, TX. The results from these tests will be used by the U.S. Army Corps of Engineers, Fort Worth District, in assessments of the erosion resistance of the Benbrook Dam with regards to possible overtopping by extreme flooding. The JETs were performed at four different locations, i.e., two locations at the lowest crest elevation and two locations at the mid-slope face of the downstream embankment. Variations in estimated critical hydraulic shear stress and erosion rate values may have been caused by differences in soil composition, i.e., when the material changed from silt/sand to clay. The resulting values of the Erodibility Coefficient, Kd, and Critical Stress, τc, are very useful information in assessing the stability of Benbrook Dam during an overtopping event. Because of the observed natural variability of the materials, combining the erosion parameters presented in this report with the drilling logs and local geology will be imperative for assessing erosion-related failure modes of Benbrook Dam.

  • Harrington Water Treatment Plant Streambank Stabilization Project gets the greenlight

    NASHVILLE, Tenn. (Dec. 9, 2021) - Lt. Col. Joseph Sahl, U.S. Army Corps of Engineers Nashville District commander, met with Project Planning Branch Chief Craig Carrington, Plan Formulation Section Chief Thomas Herbert, and Planning Project Manager Chris Pickering to sign the K.R. Harrington Water Treatment Plant Streambank Stabilization Project Partnership Agreement at the district's headquarters in the Estes Kefauver Federal Building.

  • MKARNS Nav Notice SWL 21-56 Lock 13 Tow Haulage Out of Service

    MKARNS - Tow haulage equipment at James W. Trimble Lock (NM 292.8) is out of service.

  • A look back: Word's 32 years of service

    She undertook the great responsibility of project oversight and financial analysis while her coworkers deployed in support of the 2011 Mississippi River Flood. Additionally, she quickly developed a complete understanding of the complex skills required to execute the Mississippi River and Tributaries maintenance program. These are just a few of many things Program Analyst Lisa Word accomplished before retiring after 32 years of federal service.   

  • USACE Charleston District helps manage Fort Jackson facilities

    The U.S. Army Corps of Engineers Charleston District not only builds facilities at Fort Jackson, but helps the Department of Public Works in maintaining those facilities. This partnership helps support the 45,000 soldiers who train there each year.

  • Final ribbon-cuttings close out two-day celebration blitz

    To close out the two-day sprint across five states, the Memphis District held two final ribbon-cutting ceremonies on Nov. 18, 2021. Both events celebrated construction projects completed in Arkansas and Missouri.

  • MATOC awarded with $990 million capacity

    The U.S. Army Corps of Engineers Transatlantic Middle East District awarded a Multiple Award Task Order Contract (MATOC) with a capacity of $990,000,000 to six Kingdom of Saudi Arabia (KSA) companies on Nov. 29, 2021.

  • Start planning for the 2022 camping season now

    The 2022 recreational camping and fee schedule is live on the U.S. Army Corps of Engineers Nashville District’s webpage. Recreation enthusiasts can find up-to-date information about site amenities such as: electric hookups, fees, dates of operation, visitor fees and contact numbers for all 25 campgrounds within the district.