Topographical control of large-scale sediment transport by a river valley during the 24 ka sector collapse of Asama volcano, Japan

2007 ◽  
Vol 13 (3) ◽  
pp. 217-224 ◽  
Author(s):  
Hidetsugu Yoshida ◽  
Toshihiko Sugai
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
River Valley ◽  
Sector Collapse ◽  
Asama Volcano

Large-scale vegetation mapping of the Pinega river valley (the surroundings of Golubino village, Arkhangelsk oblast)

2018 ◽  
pp. 19-39
Author(s):  
M. A. Makarova
Keyword(s):  
Plant Communities ◽  
Indicator Species ◽  
Dominant Species ◽  
Large Scale ◽  
Vegetation Mapping ◽  
River Valley ◽  
Floodplain Forests ◽  
Floodplain Vegetation ◽  
Wet Meadows ◽  
Arkhangelsk Oblast

Geobotanical survey of floodplain natural complexes near gypsum outcrops in the Pinega river valley was done in 2015. Large-scale geobotanical map of the key polygon (scale 1 : 30 000) was composed. Typological units of vegetation were selected on the basis of the composition of dominant species and groups of indicator species. Homogeneous and heterogeneous territorial units of vegetation (serial series, combinations, environmental series) were used. 53 mapped unit types (25 homogeneous types and 28 heterogeneous types) were recognized. The floodplain vegetation consists of 17 homogeneous types of plant communities, 3 series, 14 combinations and 6 ecological series. The sites of old floodplain forests, such as willow forests with Urtica sondenii rare in the Arkhangelsk region and oxbow wet meadows with Scolochloa festucacea were identified.

scholarly journals Alalakh: an account of the excavations at Tell Atchana in the Hatay, 1937–1949

2004 ◽  
Author(s):  
Leonard Woolley
Keyword(s):  
Bronze Age ◽  
Large Scale ◽  
River Valley ◽  
Early Bronze Age ◽  
Late Bronze Age ◽  
13Th Century ◽  
Gold Silver

This monograph describes large-scale excavations undertaken by Sir Leonard Woolley from 1937 to 1939, and again from 1946 to 1949, at the site of Alalakh (modern Tell Atchana) – a late Bronze Age city in the Amuq River valley of Turkey's Hatay Province. Described is the evidence of a series of superimposed palaces and temples, town defences, private houses and graves, in 17 archaeological levels reaching from late Early Bronze Age (Level XVII, c. 2200–2000 BC to Late Bronze Age (Level 0, 13th century BC). Supplementary reports describe the architecture and frescoes, sculptures, and portable objects in fired clay, gold, silver, ivory, stone, and glass.

scholarly journals Large-scale suspended sediment transport and sediment deposition in the Mekong Delta

2014 ◽  
Vol 18 (8) ◽  
pp. 3033-3053 ◽  
Author(s):  
N. V. Manh ◽  
N. V. Dung ◽  
N. N. Hung ◽  
B. Merz ◽  
H. Apel
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Large Scale ◽  
Transport Model ◽  
Mekong Delta ◽  
Sediment Dynamics ◽  
Sediment Deposition ◽  
Mineral Fertilizers ◽  
Suspended Sediment Transport ◽  
Extreme Flood

Abstract. Sediment dynamics play a major role in the agricultural and fishery productivity of the Mekong Delta. However, the understanding of sediment dynamics in the delta, one of the most complex river deltas in the world, is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains, and the scarcity of observations. This study quantifies, for the first time, the suspended sediment transport and sediment deposition in the whole Mekong Delta. To this end, a quasi-2D hydrodynamic model is combined with a cohesive sediment transport model. The combined model is calibrated using six objective functions to represent the different aspects of the hydraulic and sediment transport components. The model is calibrated for the extreme flood season in 2011 and shows good performance for 2 validation years with very different flood characteristics. It is shown how sediment transport and sediment deposition is differentiated from Kratie at the entrance of the delta on its way to the coast. The main factors influencing the spatial sediment dynamics are the river and channel system, dike rings, sluice gate operations, the magnitude of the floods, and tidal influences. The superposition of these factors leads to high spatial variability of sediment transport, in particular in the Vietnamese floodplains. Depending on the flood magnitude, annual sediment loads reaching the coast vary from 48 to 60% of the sediment load at Kratie. Deposited sediment varies from 19 to 23% of the annual load at Kratie in Cambodian floodplains, and from 1 to 6% in the compartmented and diked floodplains in Vietnam. Annual deposited nutrients (N, P, K), which are associated with the sediment deposition, provide on average more than 50% of mineral fertilizers typically applied for rice crops in non-flooded ring dike floodplains in Vietnam. Through the quantification of sediment and related nutrient input, the presented study provides a quantitative basis for estimating the benefits of annual Mekong floods for agriculture and fishery, and is an important piece of information with regard to the assessment of the impacts of deltaic subsidence and climate-change-related sea level rise on delta morphology.

Modeling large-scale cohesive sediment transport affected by small-scale biological activity

2008 ◽  
Vol 78 (3) ◽  
pp. 468-480 ◽  
Author(s):  
Bas W. Borsje ◽  
Mindert B. de Vries ◽  
Suzanne J.M.H. Hulscher ◽  
G.J. de Boer
Keyword(s):  
Biological Activity ◽  
Sediment Transport ◽  
Large Scale ◽  
Cohesive Sediment ◽  
Small Scale ◽  
Cohesive Sediment Transport

Large-scale patterns of eolian sediment transport on Venus: Predictions for Magellan

1990 ◽  
Vol 17 (9) ◽  
pp. 1365-1368 ◽  
Author(s):  
R. S. Saunders ◽  
Anthony R. Dobrovolskis ◽  
Ronald Greeley ◽  
Stephen D. Wall
Keyword(s):  
Sediment Transport ◽  
Large Scale

scholarly journals THE NEARSHORE SEDIMENT TRANSPORT STUDY

1978 ◽  
Vol 1 (16) ◽  
pp. 92 ◽  
Author(s):  
Richard J. Seymour ◽  
David B. Duane
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Surf Zone ◽  
Coastal Engineering ◽  
Predictive Tools ◽  
Transport Study ◽  
Sediment Size ◽  
Forcing Function ◽  
Nearshore Sediment Transport ◽  
Waves And Currents

The models for predicting longshore transport of sediment along straight coastlines that are presently in general use were derived empirically from very sparse measurements of both the forcing function (waves and currents) and the response function (sediment motions). A detailed treatment of these data sets is contained in Greer and Madsen (1978). In addition to the generally unsatisfactory nature of the basic measurements upon which they were based, the models may be deficient because they fail to employ such potentially significant factors as wind stress, sediment size distribution, bottom slope and spatial variations in waves and currents, including the effects of rip currents. Although these models have served certain engineering needs, there is a strong measure of uncertainty in the coastal engineering community about their general applicability. Certainly, because they are empirical rather than physically reasoned models, there is no rational means for extending their usefulness to predicting transport where coastlines are not straight -- such as the case of a tidal inlet. The economic impact of sediment transport in the nearshore regime is enormous and the need for improved predictive tools appears to be universally accepted. To be most useful, these improved models must be globally applicable. This implies very strongly that they must be based upon a thorough understanding of surf zone dynamics and the details of the response of the sediment. The surf zone flow fields are highly complex and nonlinear, implying an equally complex and difficult system of sediment responses. Characterizing the entire forcing and response functions simultaneously requires large and expensive field measurement programs that greatly exceed the present state of the art of measurement and analysis.' The approach of the last two decades of single investigators working at laboratory scale or in the ocean with a few single point measurements would not appear to ever meet these needs. However, the present costs for coastal dredging and shoreline protection, which can be measured in billions of dollars on a world scale, argue for a major undertaking to develop better predictive tools. In an attempt to satisfy these needs, an ad hoc group was formed at the Fifteenth Coastal Engineering Conference in Honolulu to plan a large scale and coordinated series of investigations leading to improved sediment transport predictive models. Less than a year later, the Nearshore Sediment Transport Study was initiated under the sponsorship of the Office of Sea Grant.

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