scholarly journals Blockage probability modeling of large wood at reservoir spillways with piers

2021 ◽  
Author(s):  
Paloma Furlan ◽  
Michael Pfister ◽  
Jorge Matos ◽  
Conceição Amado ◽  
Anton J. Schleiss
Keyword(s):  
Large Wood ◽  
Probability Modeling

scholarly journals Flume Experiments Evaluating the Efficacy of a Large Wood Trap Featuring Horizontal Rods

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1837
Author(s):  
Mayuko Furukawa ◽  
Daizo Tsutsumi ◽  
Hironori Muto ◽  
Taro Uchida ◽  
Takuro Suzuki ◽  
...  
Keyword(s):  
Relative Length ◽  
Large Wood ◽  
Basic Information ◽  
Trapping Rate ◽  
Supply Rate ◽  
Flume Experiments ◽  
Water And Sediment ◽  
Constant Rate

Large wood (LW) disasters, which often accompany sediment-related disasters, occur worldwide. To prevent and mitigate such disasters, we developed a unique LW trap featuring horizontal rods aligned with the flow. When LW enters the trap, it is scooped up by the rods and thus separated from water and sediment. We explored trapping efficacy using a flume of slope 0.087. Water circulated at a constant rate of 1.8 L/s, LW was added to the flow, and the trapping rates were measured. We focused on the relative wood length (Lw) with respect to the horizontal rod spacing (Sr), the number of LW units supplied, and the supply rate. A longer relative length (Lw/Sr) of LW was associated with a higher trapping rate. The trapping rate was also high when the LW number or supply rate was high. The critical Lw/Sr value was 1.5; below this value, LW was not trapped. This study yields the basic information needed to design traps featuring horizontal rods to mitigate LW-related disasters.

scholarly journals How Suitable is Quantile Mapping For Postprocessing GCM Precipitation Forecasts?

2017 ◽  
Vol 30 (9) ◽  
pp. 3185-3196 ◽  
Author(s):  
Tongtiegang Zhao ◽  
James C. Bennett ◽  
Q. J. Wang ◽  
Andrew Schepen ◽  
Andrew W. Wood ◽  
...  
Keyword(s):  
Joint Probability ◽  
Ensemble Model ◽  
Ensemble Spread ◽  
Quantile Mapping ◽  
Ensemble Forecasts ◽  
Probability Modeling ◽  
Satisfactory Method ◽  
Coherent Forecasts ◽  
Ensemble Model Output Statistics ◽  
Model Output Statistics

GCMs are used by many national weather services to produce seasonal outlooks of atmospheric and oceanic conditions and fluxes. Postprocessing is often a necessary step before GCM forecasts can be applied in practice. Quantile mapping (QM) is rapidly becoming the method of choice by operational agencies to postprocess raw GCM outputs. The authors investigate whether QM is appropriate for this task. Ensemble forecast postprocessing methods should aim to 1) correct bias, 2) ensure forecasts are reliable in ensemble spread, and 3) guarantee forecasts are at least as skillful as climatology, a property called “coherence.” This study evaluates the effectiveness of QM in achieving these aims by applying it to precipitation forecasts from the POAMA model. It is shown that while QM is highly effective in correcting bias, it cannot ensure reliability in forecast ensemble spread or guarantee coherence. This is because QM ignores the correlation between raw ensemble forecasts and observations. When raw forecasts are not significantly positively correlated with observations, QM tends to produce negatively skillful forecasts. Even when there is significant positive correlation, QM cannot ensure reliability and coherence for postprocessed forecasts. Therefore, QM is not a fully satisfactory method for postprocessing forecasts where the issues of bias, reliability, and coherence pre-exist. Alternative postprocessing methods based on ensemble model output statistics (EMOS) are available that achieve not only unbiased but also reliable and coherent forecasts. This is shown with one such alternative, the Bayesian joint probability modeling approach.

Does reintroducing large wood influence the hydraulic landscape of a lowland river at multiple discharges?

Ecohydrology ◽  
2017 ◽  
Vol 10 (6) ◽  
pp. e1854 ◽  
Author(s):  
Adrian Matheson ◽  
Martin Thoms ◽  
Mark Southwell ◽  
Michael Reid
Keyword(s):  
Lowland River ◽  
Large Wood

scholarly journals Flow and wake characteristics associated with large wood to inform river restoration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Isabella Schalko ◽  
Ellen Wohl ◽  
Heidi M. Nepf
Keyword(s):  
Habitat Suitability ◽  
River Restoration ◽  
Recirculation Zone ◽  
Habitat Diversity ◽  
Turbulence Level ◽  
Large Wood ◽  
River Ecosystem ◽  
Mean Velocity ◽  
Physical Model Tests ◽  
Channel Center

AbstractWood is an integral part of a river ecosystem and the number of restoration projects using log placements is increasing. Physical model tests were used to explore how the wood position and submergence level (discharge) affect wake structure, and hence the resulting habitat. We observed a von-Kármán vortex street (VS) for emergent logs placed at the channel center, while no VS formed for submerged logs, because the flow entering the wake from above the log (sweeping flow) inhibited VS formation. As a result, emergent logs placed at the channel center resulted in ten times higher turbulent kinetic energy compared to submerged logs. In addition, both spatial variation in time-mean velocity and turbulence level increased with increasing log length and decreasing submergence level. Submerged logs and logs placed at the channel side created a greater velocity deficit and a longer recirculation zone, both of which can increase the residence time in the wake and deposition of organic matter and nutrients. The results demonstrate that variation in log size and degree of submergence can be used as a tool to vary habitat suitability for different fish preferences. To maximize habitat diversity in rivers, we suggest a diverse large wood placement.

The Benefits of Including Clinical Factors in Rectal Normal Tissue Complication Probability Modeling After Radiotherapy for Prostate Cancer

2012 ◽  
Vol 82 (3) ◽  
pp. 1233-1242 ◽  
Author(s):  
Gilles Defraene ◽  
Laura Van den Bergh ◽  
Abrahim Al-Mamgani ◽  
Karin Haustermans ◽  
Wilma Heemsbergen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Normal Tissue ◽  
Normal Tissue Complication Probability ◽  
Clinical Factors ◽  
Probability Modeling

scholarly journals Application of the new Morphological Quality Index in the Cordevole river (BL, Italy)

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
E. Rigon ◽  
J. Moretto ◽  
F. Delai ◽  
L. Picco ◽  
D. Ravazzolo ◽  
...  
Keyword(s):  
Quality Index ◽  
Management Strategies ◽  
Morphological Characteristics ◽  
Site Investigation ◽  
Integrated Approach ◽  
Large Wood ◽  
River Types ◽  
River Corridor ◽  
The Eu

The evaluation of the morphological quality of rivers is essential to define the level of alteration and for implementing future management strategies that consider also hazards related to fluvial processes and channel dynamics. This type of evaluation is particularly significant for the Italian rivers, that, as in many other European countries, have a very high level of human pressure. Recently, in Italy, the National Institute for Environmental Protection and Research has promoted a methodology named IDRAIM for hydromorphological analysis of streams that pursues an integrated approach aimed at a harmonized implementation of both the EU Water Framework Directive (WFD, 2000/60/EC), and the EU Floods Directive (2007/60/EC). In this paper we present the application of the Morphological Quality Index (MQI) protocol, which is part of IDRAIM, to determine the assessment of the morphological quality of the Cordevole River. The water network (only collectors greater than thirdorder were considered), has been divided, through GIS software, into 132 river reaches of homogeneous morphological characteristics, according to the first phase of the method. At this stage the semi-automatic calculation of lateral confinement (defined by “degree of confinement” and a “confinement index”) was tried, in order to reduce the implementing time. The application of 28 indicators was made for 42 reaches representing the major river types and human pressures in the site investigation. The results showed that 48% of the analyzed reaches have a very good or good quality status, 38% have a moderate morphological quality, while only 14% have the characteristics of poor or very poor quality. The main causes that lead to a strong alteration of the terms of reference are linked to i) poor connectivity between hillslopes and river corridor, that is very important for the natural supply of sediment and large wood; ii) absence of vegetation in the river corridor, that is functional to a range of geomorphic processes; iii) presence of artificial elements, particularly the bedload interception structures in the catchment, bank protection along the reach, and the removal of sediment, large wood and vegetation.

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