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Holger Frey Christian Huggel Yves Bühler Daniel Buis Maria Dulce Burga Walter Choquevilca Felipe Fernandez Javier García Hernández Claudia Giráldez Edwin Loarte Paul Masias Cesar Portocarrero Luis Vicuña Marco Walser 《Landslides》2016,13(6):1493-1507
The town of Santa Teresa (Cusco Region, Peru) has been affected by several large debris-flow events in the recent past, which destroyed parts of the town and resulted in a resettlement of the municipality. Here, we present a risk analysis and a risk management strategy for debris-flows and glacier lake outbursts in the Sacsara catchment. Data scarcity and limited understanding of both physical and social processes impede a full quantitative risk assessment. Therefore, a bottom-up approach is chosen in order to establish an integrated risk management strategy that is robust against uncertainties in the risk analysis. With the Rapid Mass Movement Simulation (RAMMS) model, a reconstruction of a major event from 1998 in the Sacsara catchment is calculated, including a sensitivity analysis for various model parameters. Based on the simulation results, potential future debris-flows scenarios of different magnitudes, including outbursts of two glacier lakes, are modeled for assessing the hazard. For the local communities in the catchment, the hazard assessment is complemented by the analysis of high-resolution satellite imagery and fieldwork. Physical, social, economic, and institutional vulnerability are considered for the vulnerability assessment, and risk is eventually evaluated by crossing the local hazard maps with the vulnerability. Based on this risk analysis, a risk management strategy is developed, consisting of three complementing elements: (i) standardized risk sheets for the communities; (ii) activities with the local population and authorities to increase social and institutional preparedness; and (iii) a simple Early Warning System. By combining scientific, technical, and social aspects, this work is an example of a framework for an integrated risk management strategy in a data scarce, remote mountain catchment in a developing country. 相似文献
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Ernst-Jan Buis Marco Beijersbergen Giuseppe Vacanti Marcos Bavdaz David Lumb 《Experimental Astronomy》2005,20(1-3):105-113
If sensitive enough, future missions for nuclear astrophysics will be a great help in understanding supernovae explosions. In contrast to coded-mask instruments, both crystal diffraction lenses and grazing angle mirrors offer a possibility to construct a sensitive instrument to detect γ-ray lines in supernovae. We report on possible implementations of grazing angle mirrors and simulations carried out to determine their performance. 相似文献
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The subject of environmental engineering is currently of great interest. Field experiments as well as numerical models have proven their worth in this research field. An introduction to hydrodynamic modelling, coupled to the modelling of vegetation biomass is described. The developed Strive (STream RIVer Ecosystem) model is set up in the Femme (‘Flexible Environment for Mathematically Modelling the Environment’) environment and has already proven its worth in a large number of calculations (De Doncker et al., 2006 , 2008b ). Discharges and water levels are modelled together with modelling of electrical conductivity (EC). Extensive measurement campaigns are carried out to collect a large number of observations and calibration of the model is based on this data set. Furthermore, calibration methods and the discussion of this process are displayed. As a result, it is seen that the developed Strive model can model both, hydrodynamic and ecological processes, in an accurate way. The work highlights the importance of detailed determination of Manning's coefficient, dependent on discharge and amount of biomass, as an important calibration parameter for accurate modelling. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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D. Meire L. De Doncker F. Declercq K. Buis P. Troch R. Verhoeven 《Natural Hazards》2010,55(1):111-121
The (re)integration of flood storage areas in the river system is considered and proved as an effective flood protection measure.
By their (controlled) filling and emptying, inundation risks for downstream areas with higher vulnerability can be reduced.
They have an influence not only on the flood level, but also on the residence time of the water in the river ecosystem, which
is an important biological parameter. A good prediction of storage flow is therefore necessary in an integrated ecosystem
model. In such a model, which is being developed by the universities of Ghent and Antwerp, hydraulic, biological and biogeochemical
processes are coupled. In this paper, a one-dimensional hydrodynamic module of the integrated STRIVE (STReam RIVer Ecosystem)
model, which is based on the de Saint–Venant equations and solved by the Preissmann scheme, is adapted to be able to include
flow exchange with storage cells. This model is validated with experimental laboratory measurements on a small scale. The
flow between the storage cells and the river is controlled by weirs (flooded river banks). Model simulations with STRIVE are
also compared with HEC-RAS simulations. Good agreement between simulations of both models and between the STRIVE simulations
and the measurements is found. 相似文献
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Jonas Schoelynck Dieter Meire Kris Bal Kerst Buis Peter Troch Tjeerd Bouma Patrick Meire Stijn Temmerman 《Limnologica》2013,43(5):371-380
In most aquatic ecosystems, hydrodynamic conditions are a key abiotic factor determining species distribution and aquatic plant abundance. Recently, local differences in hydrodynamic conditions have been shown to be an explanatory mechanism for the patchy pattern of Callitriche platycarpa Kütz. vegetation in lowland rivers. These local conditions consists of specific areas of increased shear zones, resulting in additional plant stress and erosion of the sediment on the one hand and local decreased shear zones resulting in zones favourable to plant growth and sedimentation of bed material on the other hand. In this study, the process of this spatial plant-flow-sedimentation interaction has been illustrated quantitatively by in situ flume measurements. By disturbing the incoming discharge on a single patch in such flume, we have quantified the behaviour and influence of a C. platycarpa patch under normal field conditions (base flow). Additionally, the behaviour of a C. platycarpa patch under different conditions of hydrodynamic stress has been examined in a laboratory flume. Indeed, flexible, submerged macrophytes are capable to adapt patch dimensions with changing stream velocities. At times of modest hydrodynamic stress, the species takes a position near the water surface and optimises its leaf stand, thereby maximising its photosynthetic capacity. At times of peak discharge, the patch will bend down towards the river bed and become more confined and streamlined, as such averting the stream velocity and diminishing the risk of breaking or being uprooted.In this paper, the processes of local hydrodynamic conditions on the patch and the patch’ intriguing life strategy of avoiding negative feedback was shown. 相似文献
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Ernst-Jan Buis Marco Beijersbergen Stefan Kraft Alan Owens Francesco Quarati Sytze Brandenburg Reint Ostendorf 《Experimental Astronomy》2005,20(1-3):333-339
Recent developments of cerium-doped lanthanum-halide scintillators like LaBr3:Ce show a remarkable performance in gamma-ray spectroscopy. When high energy resolution in combination with stopping power is required they provide excellent gamma-ray detector candidates for the use in space missions. Moreover, irradiation tests have shown that such detectors are radiation tolerant. In this paper we discuss a possible application of LaBr in nuclear astrophysics missions. We show results on recent proton irradiation tests at KVI in Groningen (NL) and discuss the damage and activation effects after irradiation. A possible implementation for a focal plane detector in a gamma-ray telescope and the expected performance is presented. 相似文献
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For conventional radiation detectors fabricated from compound semi-conductors, the wide disparity between the transport properties
of the electron and holes, means that detector performances are limited by the carrier with the poorest mobility-lifetime
product (μτ). Finite drift lengths introduce an energy dependent depth term into the charge collection process, which effectively
limit maximum detection volume to tens of mm3 – entirely unsuitable for the detection of gamma-rays. The recent introduction of the coplanar-grid charge-sensing techniques
has overcome this problem by essentially discarding the carrier with the poorest transport properties, thus permitting high
spectral resolution and high detection efficiency. For example, energy resolutions of 2% full-width half-maximum at 662 keV
have been demonstrated with coplanar-grid CdZnTe detectors of volumes up to 2 cm3. Further improvements in detector performance and yield are being pursued through refinements in electrode design and material
quality. Because coplanar-grid CdZnTe detectors can operate at room temperature, they are ideally suited for applications
requiring portability, small size, or low power consumption such as planetary space missions. Other potential applications
include well logging, medical diagnostics, and gamma-ray astronomy. We discuss the feasibility and design of a solid state
gamma-ray detector based on CdZnTe and compare its performance to a large volume Ge detector. As will be shown, a significant
improvement can be made if T1Br is used as the detection medium. 相似文献
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In arid climate regions, redistribution of runoff water is highly relevant for vegetation development. The process of water redistribution at catchment scale is studied with the landscape process model LAPSUS, mainly used for erosion and sedimentation modelling. LAPSUS, formerly applied in Mediterranean climates, is modified to deal with the arid climate of the Negev Desert of Israel. Daily event based model runs were used instead of yearly model runs, and the infiltration module was modified to better represent the spatial diversity in water availability in an arid catchment. The model is calibrated for two small catchments in the Negev Desert of Israel, Halluqim and Avdat. First, a sensitivity analysis of the modified LAPSUS is performed. Pore volume appears to have an especially strong influence on the modelling results. Second, the capability of LAPSUS to deal with varying surface characteristics is assessed by comparing the water redistribution patterns in the two catchments with field data. Simulation results demonstrate that the catchments respond very differently to precipitation. Water redistribution is larger in the dominantly bedrock covered Halluqim compared to the dominantly loess covered catchment of Avdat. Consequently, Halluqim has more positions with water accumulation than Avdat, and can sustain a larger vegetation cover, including Mediterranean species. Finally, the modelled infiltration patterns are compared with vegetation cover in the catchments. The results indicate that there is a broad agreement between infiltration and vegetation patterns, but locally there is a strong mismatch, indicating that some of the involved processes are still missing from the model. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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