23 May 2022

Ballistic Protection Using Snow

Abstract: Small (5.56 mm, 7.62 mm and 9 mm) and medium (12.7 mm) arms rounds were fired at snow-filled 1.5m cubic gabions in a mid-winter condition in Fairbanks, Alaska. The rounds were excavated and penetration by each ammunition type was measured. A distribution and average of penetration depth was determined. All 320 rounds fired were captured within 1.5m after entering the snow barrier. Comparison with published models of ballistics penetration of snow showed mixed results with several matching our data within 10% and all but one within 32%. However, most of these models are simplistic in that they accommodate limited variables and therefore may not be expected to perform well in all settings. We conclude that snow-based ballistics protection structures can be quickly and efficiently erected in suitable environments and with minimal size, can provide reliable protection against small and medium arms fire.

20 May 2022

Southern Flying Squirrels (Glaucomys volans) as Major Predators of Avian Nest Boxes

Abstract: Bird population dynamics are strongly affected by the ability to successfully reproduce, and nest predation is the primary cause of reproductive failure for most birds. Efforts to understand nest predation and manage its effects on species of conservation concern require knowledge of the ecology of associated predator assemblages. Recently, studies using cameras to record events at nests have illuminated this previously under-studied avian life stage, but such studies have been largely limited to open-cup nests. Cavity nests may be depredated by a different suite of predators and incubating or brooding females occupying such nests may be more vulnerable to predation relative to open-cup nests. Here, we used motion-activated, infrared trail cameras to record predators of artificial nest boxes in a Pinus palustris Mill. (Longleaf Pine) forest in southern Alabama. Although Glaucomys Volans L. (Southern Flying Squirrel) have only rarely been captured on film preying on nests, we found them to be responsible for the vast majority (84%) of bird-nest depredations at nest boxes, and these depredations contributed to a surprisingly low overall rate of nest success (~20%). These results may have implications for the conservation of birds that nest in artificial cavities in Longleaf Pine forests and highlight the importance of further studies on predator assemblages and their effects on nesting birds.

20 May 2022

Low-Sill Control Structure Gate Load Study

Abstract: The effort performed here describes the process to determine the gate lifting loads at the Low-Sill Control Structure. To measure the gate loads, a 1:55 Froude-scaled model of the Low-Sill Control Structure was tested. Load cells were placed on 3 of the 11 gates. Tests evaluated the gate loads for various hydraulic heads across the structure. A total of 109 tests were conducted for 14 flows with each flow having two gate settings provided by the United States Army Corps of Engineers, New Orleans District. The load data illustrated the potential for higher gate lifting loads (GLL) to occur at the mid-range gate opening (Go) for Gates 3 and 6. While for Gate 10, the highest GLL (452 kips, maximum load in testing) was at a Go = 4.2 ft. Conversely, for the low-flow bays, the highest load occurred at Go = 24.86 ft.

9 May 2022

Three-Dimensional Underseepage Evaluation for Profit Island Vicinity Levee, North of Baton Rouge, Louisiana

Abstract: This project developed a three-dimensional (3D) seepage model to evaluate efficiency of 84 relief wells and factors of safety (FoS) along the Profit Island vicinity levee (PIVL), north of Baton Rouge, Louisiana. The PIVL model was built based on US Geological Survey MODFLOW-USG. Moreover, a 3D seepage model of RocScience RS3 was also built for a specific study of relief well experiments conducted by the US Army Corps of Engineers in the 1930s and 1940s. The PIVL model was calibrated with measured piezometric head data and relief well flow rates in 1997. Six flood scenarios were conducted: the extreme flood (56 feet), design flood (52.4 feet), 1997 flood (50 feet), 2008 flood (49.22 feet), 2017 flood (45.55 feet), and 2018 flood (49.1 feet). The modeling results show that FoS are all above 1.5 given relief wells at the 1997 design condition. FoS calculated by the blanket theory are more conservative than those by the PIVL model because designed discharge rates were not observed in the field. In comparison with measured flow rates in 2008, the PIVL modeling result indicates potential clogging at many relief wells. New piezometric data and well discharge data are recommended to re-evaluate factors of safety.

6 May 2022

Soil and Vegetation Responses to Amendment with Pulverized Classified Paper Waste

Abstract: The United States Army produces a significant amount of classified paper waste that is pulverized to a fine consistency unsuitable for recycling. However, cheap, high quality organic materials such as classified paper waste are useful as soil amendments. The objective of this research was to evaluate the utilization of pulverized classified paper waste as a soil amendment to improve soil health and increase establishment of desirable native grasses on degraded Army training lands. Paper was applied at rates of 9 to 72 Mg ha-1 to two soil types at Fort Polk, LA: an alfisol (very fine sandy loam - Fine, smectitic, thermic Chromic Vertic Hapludalfs) and an ultisol (loamy fine sandy - Loamy, siliceous, semiactive, thermic Arenic Paleudults). These are common soil orders found on military training lands nationwide and represent fertile (alfisol) and unfertile (ulitsol) soils. Vegetation and soils were monitored over 2 growing seasons. No increase in heavy metals were observed in soils. Extensive analysis showed very low levels of regulated contaminants in the paper, but most were below detection limits. The ultisol site showed improved soil physical and chemical properties, while desirable vegetation benefitted from nutrient immobilization at the alfisol site. Based on the results of this study, applying pulverized paper waste to soil at a rate of 35.9 Mg ha-1 is recommended. Application of paper waste to soils had no adverse environmental effects, improved soil physiochemical properties, and facilitated establishment of desirable native vegetation.

5 May 2022

Waterborne Geophysical Investigation to Assess Condition of Grouted Foundation: Old River Control Complex – Low Sill Structure, Concordia Parish, Louisiana

Abstract: The Old River Low Sill Structure (ORLSS) at the Old River Control Complex (ORCC) in Concordia Parish, LA, is a steel pile-founded, gated reinforced-concrete structure that regulates the flow of water into the Atchafalaya River to prevent an avulsion between the Mississippi River and the Atchafalaya River. A scour hole that formed on the southeast wall of ORLSS during the Mississippi River flood of 1973 was remediated with riprap placement and varied mixtures of self-leveling, highly pumpable grout. Non-invasive waterborne geophysical surveys were used to evaluate the distribution and condition of the grout within the remediated scour area. Highly conductive areas were identified from the surveys that were interpreted to consist mostly of grout. Resistive responses, likely representing mostly riprap and/or sediment, were encountered near the remediated scour area periphery. A complex mixture of materials in the remediated scour area is interpreted by the more gradual transitions in the geophysical response. Survey measurements immediately beneath ORLSS were impeded by the abundance of steel along with the structure itself. The survey results and interpretation provide a better understanding of the subsurface properties of ORLSS.

4 May 2022

AIS Data Case Study: Dredge Material Placement Site Evaluation in Frederick Sound near Petersburg, Alaska

Abstract: The purpose of this Coastal and Hydraulics Laboratory Technical Note (CHETN) is to present an application of historic vessel position information acquired through the Automatic Identification System (AIS), which provides geo-referenced and time-stamped vessel position information. The US Army Corps of Engineers, Alaska District (POA), needed to evaluate potential placement sites for dredged material near Petersburg, AK, and possible impacts to navigation were considered as part of the evaluation process.

4 May 2022

Calculation of Levee-Breach Widening Rates

Abstract: Inundation modeling is often conducted for levee systems to understand current flood risks. The extent of inundation caused by a breach in the levee is highly influenced by the widening rate of the levee breach. This study presents an approach for calculating levee-breach widening rates based on average flow velocity through the breach, embankment height, and erosion characteristics of the soil. Estimates of soil erodibility are derived through an analysis of the measurements of soil erodibility presented in the National Cooperative Highway Research Program (NCHRP) Report 915 database. Levee-breach widening rate curves are calculated based on these erosion properties to demonstrate the approach, and default curves are presented for typical levees built from coarse-grained soils and fine-grained soils. While the most accurate approach for a site is to calculate site-specific widening rate curves based on estimates of local soil erodibility, the default curves presented provide a suitable starting point for initial inundation modeling.

3 May 2022

Sediment Budget Analysis System (SBAS) 2020 User’s Guide: Version 1.0

Abstract: This special report acts as a user’s guide for the Sediment Budget Analysis System (SBAS) toolbox within ArcGIS Pro. The SBAS toolbox is a free toolset that allows the user to create and visualize a sediment budget using ArcGIS Pro. Included in this report are instructions on how to download the toolbox and create a sediment budget.

2 May 2022

Summary of Ground-Based Snow Measurements for the Northeastern United States

ABSTRACT: Snow is an important resource for both communities and ecosystems of the Northeastern United States. Both flood risk management and water supply forecasts for major municipalities, including New York City, depend on the collection of snowpack information. Therefore, the purpose of this study is to summarize all of the snowpack data from ground-based networks currently available in the Northeast. The collection of snow-depth and snow water equivalent information extends back several decades, and there are over 2,200 active sites across the region. Sites are distributed across the entire range of elevations in the region. The number of locations collecting snow information has increased substantially in the last 20 years, primarily from the expansion of the CoCoRaHS (Community Collaborative Rain, Hail, and Snow) network. Our summary of regional snow measurement locations provides a foundation for future studies and analysis, including a template for other regions of the United States.