• Complete: Scour repairs downstream of St. Francis bridge

    The Memphis District has done it again. The Memphis District Commander, Col. Zachary Miller, district leadership, Project Partner Rob Rash, and Project Delivery Team members all gathered to celebrate, with a ribbon-cutting, the completion of yet another significant project involving riverbank armoring. Along with our longtime partner, the St. Francis Levee District of Arkansas, represented by Rob Rash, the Memphis District awarded a contract to A Rock Construction Co., Inc., in the amount of $2,786,197, to remove debris, reshape the channel, and armor the bank with more than 27,000 tons of stone along the CR736 Bridge over the St. Francis River in St. Francis County, Arkansas.
  • USACE announces plan for dry season flows to Caloosahatchee from Lake Okeechobee

    The U.S. Army Corps of Engineers (USACE) Jacksonville District has announced a plan to increase the amount of water being released from Lake Okeechobee to the Caloosahatchee Estuary.
  • 21-002 Dworshak Dam releases to fluctuate between 1,700 and 7,000 cfs in first half of February

    AHSAHKA, Idaho – Reservoir managers will decrease Dworshak Dam releases on Friday evening, Jan. 29, to 1,700 cubic feet per second (cfs). This flow is expected to remain constant until Feb. 8. Flows may vary daily from Feb. 8 to Feb. 15 in the range of 1,700 to 7,000 cfs.
  • Corps seeks public comment on Sheldon streambank protection project

    ST. PAUL, Minn. –The U.S. Army Corps of Engineers, St. Paul District, seeks comments on a draft feasibility report and environmental assessment for the proposed Sheldon Road Bridge streambank protection project near Sheldon, North Dakota.
  • Environmental Applications of 3D Printing Polymer Composites for Dredging Operations

    Abstract: This Dredging Operations Environmental Research (DOER) technical note disseminates novel methods to monitor and reduce contaminant mobility and bioavailability in water, sediments, and soils. These method advancements are enabled by additive manufacturing (i.e., three-dimensional [3D] printing) to deploy and retrieve materials that adsorb contaminants that are traditionally applied as unbound powders. Examples of sorbents added as amendments for remediation of contaminated sediments include activated carbon, biochar, biopolymers, zeolite, and sand caps. Figure 1 provides examples of sorbent and photocatalytic particles successfully compounded and 3D printed using polylactic acid as a binder. Additional adsorptive materials may be applicable and photocatalytic materials (Friedmann et al. 2019) may be applied to degrade contaminants of concern into less hazardous forms. This technical note further describes opportunities for U.S. Army Corps of Engineers (USACE) project managers and the water and sediment resource management community to apply 3D printing of polymers containing adsorptive filler materials as a prototyping tool and as an on-site, on-demand manufacturing capability to remediate and monitor contaminants in the environment. This research was funded by DOER project 19-13, titled “3D Printed Design for Remediation and Monitoring of Dredged Material.”
  • Long-Term Durability of Cold Weather Concrete: Phase II

    Abstract: Recent laboratory results confirm that it is possible to protect concrete from freezing solely using chemical admixtures and indicate that the amount of admixture required may be significantly less than previously recommended. Researchers have also verified that admixture-based freeze protection can produce concrete that is durable to winter exposure for a minimum of 20 years, through petrographic examination of core specimens obtained from past field demonstrations. Freeze protection for concrete using chemical admixtures alone has been an area of active research for 3 decades; however, the most recent methodology recommends very high addition rates of accelerating and corrosion inhibiting admixtures, which result in significant challenges, including slump loss, rapid setting, and potentially excessive temperature rise. As part of a laboratory study, researchers systematically varied the dosage of freeze protection admixtures used in concrete cured in a 23 °F environment. Preliminary findings indicate that a 50% reduction in admixture dose maintained adequate freeze protection and resulted in compressive strengths exceeding those of room-temperature controls at 7 and 28 days. The combination of improved handling, reduced cost, and verified durability associated with the use of admixtures for freeze protection makes a compelling case for broader adoption of this technique in winter operations
  • Demonstration of Acoustic Sensing Techniques for Fuel-Distribution System Condition Monitoring: Final Report on Project F07-AR07

    Abstract: Leaks in fuel storage tanks and distribution piping systems have been identified as a mission-critical problem by the Department of Defense and the U.S. Army. Fuel system leaks are often hard to locate and virtually inaccessible for efficient repair because the piping is often installed under a concrete pad or tarmac. Leak repair could cost up to $2,000, and the cost of cleanup and remediation for fuel spills can exceed $50,000. In this project an acoustic remote sensing system was installed to monitor an Army heliport refueling system to determine whether it could detect and accurately locate fuel leaks using computer software technologies to distinguish acoustic leakage signatures from normal fuel system operational noise.
  • Simulations of Shoreline Changes along the Delaware Coast

    Abstract: This technical report presents two applications of the GenCade model to simulate long-term shoreline evolution along the Delaware Coast driven by waves, inlet sediment transport, and longshore sediment transport. The simulations also include coastal protection practices such as periodic beach fills, post-storm nourishment, and sand bypassing. Two site-specific GenCade models were developed: one is for the coasts adjacent to the Indian River Inlet (IRI) and another is for Fenwick Island. In the first model, the sediment exchanges among the shoals and bars of the inlet were simulated by the Inlet Reservoir Model (IRM) in the GenCade. An inlet sediment transfer factor (γ) was derived from the IRM to quantify the capability of inlet sediment bypassing, measured by a rate of longshore sediments transferred across an inlet from the updrift side to the downdrift side. The second model for the Fenwick Island coast was validated by simulating an 11-year-long shoreline evolution driven by longshore sediment transport and periodic beach fills. Validation of the two models was achieved through evaluating statistical errors of simulations. The effects of the sand bypassing operation across the IRI and the beach fills in Fenwick Island were examined by comparing simulation results with and without those protection practices. Results of the study will benefit planning and management of coastal sediments at the sites.
  • Mississippi River Adaptive Hydraulics Model Development and Evaluation, Commerce to New Madrid, Missouri, Reach

    Abstract: A numerical, two-dimensional hydrodynamic model of the Mississippi River, from Thebes, IL, to Tiptonville, TN (128 miles/206 km), was developed using the Adaptive Hydraulics model. The study objective assessed current patterns and flow distributions and their possible impacts on navigation due to Birds Point New Madrid Floodway (BPNMF) operations and the Len Small (LS) levee break. The model was calibrated to stage, discharge, and velocity data for the 2011, 2015–2016, and 2017 floods. The calibrated model was used to run four scenarios, with the BPNMF and the LS breach alternately active/open and inactive/closed. Effects from the LS breach being open are increased river velocities upstream of the breach, decreased velocities from the breach to Thompson Landing, no effects on velocity below the confluence, and cross-current velocities greater than 3.28 ft/s (1.0 m/s) within 1186.8 ft (60 m) of the bankline revetment. Effects from BPNMF operation are increased river velocities above the confluence, decreased velocities from the BPNMF upper inflow crevasse (Upper Fuseplug) to New Madrid, cross-current velocities greater than 1.5 ft/s (0.5 m/s) only near the right bank where flow re-enters the river from the BPNMF lower inflow/outflow crevasse Number 2 (Lower Fuseplug) and St. Johns Bayou.
  • Optical and Acoustical Measurement of Ballistic Noise Signatures

    Abstract: Supersonic projectiles in air generate acoustical signatures that are fundamentally related to the projectile’s shape, size, and velocity. These characteristics influence various mechanisms involved in the generation, propagation, decay, and coalescence of acoustic waves. To understand the relationships between projectile shape, size, velocity, and the physical mechanisms involved, an experimental effort captured the acoustic field produced by a range of supersonic projectiles using both conventional pressure sensors and a schlieren imaging system. The results of this ongoing project will elucidate those fundamental mechanisms, enabling more sophisticated tools for detection, classification, localization, and tracking. This paper details the experimental setup, data collection, and preliminary analysis of a series of ballistic projectiles, both idealized and currently in use by the U.S. Military.