Applying geomorphological principles and engineering science to develop a phased sediment management plan for Mount St Helens, Washington

Thirty-seven years post-eruption, erosion of the debris avalanche at Mount St. Helens continues to supply sediment to the Toutle-Cowlitz River system in quantities that have the potential to lower the Level of Protection (LoP) against flooding unacceptably, making this one of the most protracted gravel-bed river disasters to date. The Portland District, US Army Corps of Engineers (USACE) recently revised its long-term plan for sediment management (originally published in 1985), in order to maintain the LoP above the Congressionally-authorised level, while reducing impacts on fish currently listed under the Endangered Species Act, and minimising the overall cost of managing sediment derived from erosion at Mount St Helens. In revising the plan, the USACE drew on evidence gained from sediment monitoring, modelling and uncertainty analysis, coupled with assessment of future LoP trends under a baseline scenario (continuation of the 1985 sediment management strategy) and feasible alternatives. They applied geomorphological principles and used engineering science to develop a Phased Sediment Management Plan that allows for uncertainty concerning future sediment yields by implementing sediment management actions only as, and when, necessary. The phased plan makes best use of the potential to enhance the sediment trap efficiency and storage capacity of the existing Sediment Retention Structure (SRS) by incrementally raising its spillway and using novel hydraulic structures to build islands in the NFTR and steepen the gradient of the sediment plain upstream of the structure. Dredging is held in reserve, to be performed only when necessary to react to unexpectedly high sedimentation events or when the utility of other measures has been expended. The engineering-geomorphic principles and many of the measures in the Phased Sediment Management Plan are transferrable to other gravel-bed river disasters. The overriding message is that monitoring and adaptive management are crucial components of long-term sediment-disaster management, especially in volcanic landscapes where future sediment yields are characterised by uncertainty and natural variability

Reconstruction of a flash flood with large wood transport and its influence on hazard patterns in an ungauged mountain basin

The reconstruction of past flash floods in ungauged basins leads to a high level of uncertainty, which increases if other processes are involved such as the transport of large wood material. An important flash flood occurred in 1997 in Venero Claro (Central Spain), causing significant economic losses. The wood material clogged bridge sections, raising the water level upstream. The aim of this study was to reconstruct this event, analysing the influence of woody debris transport on the flood hazard pattern. Because the reach in question was affected by backwater effects due to bridge clogging, using only high water mark or palaeostage indicators may overestimate discharges, and so other methods are required to estimate peak flows. Therefore, the peak discharge was estimated (123±18 m3 s–1) using indirect methods, but one-dimensional hydraulic simulation was also used to validate these indirect estimates through an iterative process (127± 33 m3 s–1) and reconstruct the bridge obstruction to obtain the blockage ratio during the 1997 event (~48%) and the bridge clogging curves. Rainfall–Runoff modelling with stochastic simulation of different rainfall field configurations also helped to confirm that a peak discharge greater than 150 m3 s–1 is very unlikely to occur and that the estimated discharge range is consistent with the estimated rainfall amount (233± 27 mm). It was observed that the backwater effect due to the obstruction (water level ~7 m) made the 1997 flood (~35-year return period) equivalent to the 50-year flood. This allowed the equivalent return period to be defined as the recurrence interval of an event of specified magnitude, which, where large woody debris is present, is equivalent in water depth and extent of flooded area to a more extreme event of greater magnitude. These results highlight the need to include obstruction phenomena in flood hazard analysis. Copyright © 2012 John Wiley & Sons, LtdWe express our gratitude to the Spanish Ministry of Science and Innovation for financial support. This work was funded by the MAS Dendro-Avenidas project (CGL2010-19274) and the Geological Survey of Spain (IGME). We are grateful to the Tagus Water Authority, Environment Department of Castilla y Leon in avila, Caja avila, Asocio de avila and Navaluenga Council for their collaboration. Our special thanks to forester Jose Luis Galan for his assistance in the field. We would also like to mention Juan Ballesteros, Ignacio Gutierrez, Tasio Fernandez, Leticia Salas, Carolina Guardiola and angel Prieto for contributing suggestions and interesting discussions that significantly improved this paper. Thanks to the contribution of two anonymous reviewers, which improved the quality of the early version of this manuscript.Ruiz-Villanueva, V.; Bodoque, J.; Díez-Herrero, A.; Eguíbar Galán, MÁ.; Pardo-Igúzquiza, E. (2012). Reconstruction of a flash flood with large wood transport and its influence on hazard patterns in an ungauged mountain basin. Hydrological Processes. (9433):1-14. https://doi.org/10.1002/hyp.9433S114943

Angle of Incidence Effects on Far-Field Positive and Negative Phase Blast Parameters

The blast overpressure acting on a rigid target is known to vary between the normally reflected overpressure and the incident overpressure as a function of the angle between the target and the direction of travel of the blast wave. Literature guidance for determining the exact effects of angle of incidence are unclear, particularly when considering the negative phase. This paper presents the results from a series of well controlled experiments where pressure transducers are used to record the pressure-time history acting on the face of a large, rigid target at various angles of incidence for varying sizes of hemispherical PE4 charge and stand-off distances. The test data demonstrated remarkable repeatability, and excellent agreement with semi-empirical predictions for normally reflected overpressures. The oblique results show that peak overpressure, impulse and duration are highly dependent on angle of incidence for the positive phase, and are invariant of angle of incidence for the negative phase

ETL-0254, Terrain analysis procedural guide for soil, February 1981

This report is one in a series of terrain analysis procedural guides being developed in support of the Topographic Support System (TSS). It was written specifically for a U.S. Army terrain analyst and presents the step-by- step methods needed for extraction, reducing, and recording soil information on a factor overlay and supporting data table. It is a contribution to the Department of Defense terrain intelligence effort. The report contains a detailed bibliography and a lengthy glossary

ETL-0254, Terrain analysis procedural guide for soil, February 1981

This report is one in a series of terrain analysis procedural guides being developed in support of the Topographic Support System (TSS). It was written specifically for a U.S. Army terrain analyst and presents the step-by- step methods needed for extraction, reducing, and recording soil information on a factor overlay and supporting data table. It is a contribution to the Department of Defense terrain intelligence effort. The report contains a detailed bibliography and a lengthy glossary

Flood realities, perceptions, and the depth of divisions on climate

Research has led to broad agreement among scientists that anthropogenic climate change is happening now and likely to worsen. In contrast to scientific agreement, US public views remain deeply divided, largely along ideological lines. Science communication has been neutralised in some arenas by intense counter-messaging, but as adverse climate impacts become manifest they might intervene more persuasively in local perceptions. We look for evidence of this occurring with regard to realities and perceptions of flooding in the northeastern US state of New Hampshire. Although precipitation and flood damage have increased, with ample news coverage, most residents do not see a trend. Nor do perceptions about past and future local flooding correlate with regional impacts or vulnerability. Instead, such perceptions follow ideological patterns resembling those of global climate change. That information about the physical world can be substantially filtered by ideology is a common finding from sociological environment/society research

Anomalous Low States and Long Term Variability in the Black Hole Binary LMC X-3

Rossi X-ray Timing Explorer observations of the black hole binary LMC X-3 reveal an extended very low X-ray state lasting from 2003 December 13 until 2004 March 18, unprecedented both in terms of its low luminosity (>15 times fainter than ever before seen in this source) and long duration (~3 times longer than a typical low/hard state excursion). During this event little to no source variability is observed on timescales of ~hours-weeks, and the X-ray spectrum implies an upper limit of 1.2x10^35 erg s^-1. Five years later another extended low state occurs, lasting from 2008 December 11 until 2009 June 17. This event lasts nearly twice as long as the first, and while significant variability is observed, the source remains reliably in the low/hard spectral state for the ~188 day duration. These episodes share some characteristics with the "anomalous low states" in the neutron star binary Her X-1. The average period and amplitude of the variability of LMC X-3 have different values between these episodes. We characterize the long-term variability of LMC X-3 before and after the two events using conventional and nonlinear time series analysis methods, and show that, as is the case in Her X-1, the characteristic amplitude of the variability is related to its characteristic timescale. Furthermore, the relation is in the same direction in both systems. This suggests that a similar mechanism gives rise to the long-term variability, which in the case of Her X-1 is reliably modeled with a tilted, warped precessing accretion disk.Comment: 10 pages, 7 figures. Accepted for publication in Ap

Influence of mechanical and geometrical properties of embedded long-gauge strain sensors on the accuracy of strain measurement

In many civil and geotechnical applications it is of interest to monitor the strain deep inside the structure; consequently, it is necessary to embed the sensors into the structure's material. Construction and geotechnical materials, such as concrete and soil, can be affected by local defects, e.g. cracks, air pockets and inclusions. To monitor these materials at a structural level it is necessary to use long-gauge sensors. As the sensor has to be embedded in the host material, its presence causes perturbation of the strain field and influences the accuracy of the strain measurement. The aim of this research was to identify the critical parameters that influence the accuracy of the strain measurement, to study how these parameters affect the accuracy, and to give recommendations for sensor users. The study was based on finite element analysis and all involved materials were assumed to have the MöhrCoulomb elastic, perfectly plastic behavior. A suitability of the numerical model for the analysis was verified using the experimental results of two cases reported in the literature and one on-site application. The study revealed that the most important parameters that influence the accuracy of the strain measurement are the goodness of interaction (strain transfer) between the host material and the anchor pieces of the sensor, the ratio between equivalent Young's modulus of the sensor and the Young's modulus of the host material, the radius of the anchor piece and the gauge length. The numerical model and parametric study are presented in detail along with practical recommendations. © 2012 IOP Publishing Ltd.The authors would like to thank the Spanish Ministry of Education, with support received under the National Program for Mobility of Researchers (O.M. EDU/1456/2010, ref. PR2010-0293) which enabled the joint work that made this study possible. The Streicker Bridge project was realized with help of Turner Construction Co., HNTB, AG Construction Corp., Vollers Excavating & Constr., SMARTEC SA, Micron Optics, Princeton Facilities, and staff and students of CEE department of Princeton University.Calderón García, PA.; Glisic, B. (2012). Influence of mechanical and geometrical properties of embedded long-gauge strain sensors on the accuracy of strain measurement. Measurement Science and Technology. (23):1-15. https://doi.org/10.1088/0957-0233/23/6/065604S11523Glišić, B., & Inaudi, D. (2007). Fibre Optic Methods for Structural Health Monitoring. doi:10.1002/9780470517819Ansari, F. (2007). Practical Implementation of Optical Fiber Sensors in Civil Structural Health Monitoring. Journal of Intelligent Material Systems and Structures, 18(8), 879-889. doi:10.1177/1045389x06075760Li, H.-N., Zhou, G.-D., Ren, L., & Li, D.-S. (2009). Strain Transfer Coefficient Analyses for Embedded Fiber Bragg Grating Sensors in Different Host Materials. Journal of Engineering Mechanics, 135(12), 1343-1353. doi:10.1061/(asce)0733-9399(2009)135:12(1343)Torres, B., Payá-Zaforteza, I., Calderón, P. A., & Adam, J. M. (2011). Analysis of the strain transfer in a new FBG sensor for Structural Health Monitoring. Engineering Structures, 33(2), 539-548. doi:10.1016/j.engstruct.2010.11.012Kesavan, K., Ravisankar, K., Parivallal, S., Sreeshylam, P., & Sridhar, S. (2010). Experimental studies on fiber optic sensors embedded in concrete. Measurement, 43(2), 157-163. doi:10.1016/j.measurement.2009.08.010Azenha, M., Faria, R., & Ferreira, D. (2009). Identification of early-age concrete temperatures and strains: Monitoring and numerical simulation. Cement and Concrete Composites, 31(6), 369-378. doi:10.1016/j.cemconcomp.2009.03.004Glisic, B. (2011). Influence of the gauge length on the accuracy of long-gauge sensors employed in monitoring of prismatic beams. Measurement Science and Technology, 22(3), 035206. doi:10.1088/0957-0233/22/3/035206Leng, J. S., Winter, D., Barnes, R. A., Mays, G. C., & Fernando, G. F. (2006). Structural health monitoring of concrete cylinders using protected fibre optic sensors. Smart Materials and Structures, 15(2), 302-308. doi:10.1088/0964-1726/15/2/009Calderón, P. A., Adam, J. M., Ivorra, S., Pallarés, F. J., & Giménez, E. (2009). Design strength of axially loaded RC columns strengthened by steel caging. Materials & Design, 30(10), 4069-4080. doi:10.1016/j.matdes.2009.05.014Adam, J. M., Ivorra, S., Pallarés, F. J., Giménez, E., & Calderón, P. A. (2009). Axially loaded RC columns strengthened by steel caging. Finite element modelling. Construction and Building Materials, 23(6), 2265-2276. doi:10.1016/j.conbuildmat.2008.11.014Adam, J. M., Ivorra, S., Pallares, F. J., Jiménez, E., & Calderón, P. A. (2008). Column–joint assembly in RC columns strengthened by steel caging. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 161(6), 337-348. doi:10.1680/stbu.2008.161.6.337Adam, J. M., Ivorra, S., Pallares, F. J., Giménez, E., & Calderón, P. A. (2009). Axially loaded RC columns strengthened by steel cages. Proceedings of the Institution of Civil Engineers - Structures and Buildings, 162(3), 199-208. doi:10.1680/stbu.2009.162.3.199Johansson, M., & Gylltoft, K. (2001). Structural behavior of slender circular steel-concrete composite columns under various means of load application. Steel and Composite Structures, 1(4), 393-410. doi:10.12989/scs.2001.1.4.393Johansson, M., & Gylltoft, K. (2002). Mechanical Behavior of Circular Steel–Concrete Composite Stub Columns. Journal of Structural Engineering, 128(8), 1073-1081. doi:10.1061/(asce)0733-9445(2002)128:8(1073

The infrastructural power of the military: The geoeconomic role of the US Army Corps of Engineers in the Arabian Peninsula

In analysing the role of the US in the global expansion of capitalist relations, most critical accounts see the US military’s invasion and conquest of various states as paving the way for the arrival of US businesses and capitalist relations. However, beyond this somewhat simplified image, and even in peacetime, the US military has been a major geoeconomic actor that has wielded its infrastructural power via its US Army Corps of Engineers’ overseas activities. The transformation of global economies in the 20th century has depended on the capitalisation of the newly independent states and the consolidation of liberal capitalist relations in the subsequent decades. The US Army Corps of Engineers has not only extended lucrative contracts to private firms (based not only in the US and host country, but also in geopolitically allied states), but also, and perhaps most important, has itself established a grammar of capitalist relations. It has done so by forging both physical infrastructures (roads, ports, utilities and telecommunications infrastructures) and virtual capitalist infrastructures through its practices of contracting, purchasing, design, accounting, regulatory processes and specific regimes of labour and private property ownership