scholarly journals Overnight formation of a bouldery alluvial fan by a torrential rain in a granitic mountain (Mt. Seoraksan, Republic of Korea)

2021 ◽  
Vol 19 (2) ◽  
pp. 5-11
Author(s):  
Jisu Kim ◽  
Kyung Sik Woo ◽  
Kwang Choon Lee ◽  
Young Kwan Sohn ◽  
Howard Harper

Mt. Seoraksan, Korea, is a rugged granitic mountain where extremely steep slopes and strongly seasonal rainfall have facilitated bedrock exposure and geomorphic changes mainly by rockfalls and streamflows. Although the environment was not suitable for alluvial fan formation, a bouldery alluvial fan, 170 m long and 330 m wide, formed overnight by a heavy summer rain in 2006. The fan consists of several meter-high boulder mounds and gently undulating cobble bars/sheets that are arranged in a fluvial longitudinal bar-like pattern. They are interpreted to have formed by highly competent and turbulent sheetfloods, which temporarily had the properties of hyperconcentrated flood flows. Formation of the whole alluvial fan by a single, casual hydro-meteorological event is inferred to have been possible because a threshold condition was reached in the source area. A rainfall event, which would have had no extreme effects before reaching the threshold, could probably trigger massive remobilization of bouldery sediments on the valley floors. The Seoraksan alluvial fan thus demonstrates the role of a geomorphic threshold in causing drastic changes in the hydrologic performance of the watershed. The morphology and sedimentology of the Seoraksan alluvial fan suggest that the fan is a modern example of a sheetflood-dominated alluvial fan, which has largely been ignored in spite of their potential diversity and abundance in glacial to periglacial, tropical, and temperate environments.

2019 ◽  
Vol 18 ◽  
pp. 298-303
Author(s):  
Soojin Kim ◽  
Ae Kyung Park ◽  
Jin Seok Kim ◽  
Jungsun Park ◽  
Eunkyung Shin ◽  
...  

2016 ◽  
Vol 125 (3) ◽  
pp. 475-498 ◽  
Author(s):  
P V Rajesh ◽  
S Pattnaik ◽  
D Rai ◽  
K K Osuri ◽  
U C Mohanty ◽  
...  

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1227 ◽  
Author(s):  
Russell Adams ◽  
Paul Quinn ◽  
Nick Barber ◽  
Sim Reaney

It is well known that soil, hillslopes, and watercourses in small catchments possess a degree of natural attenuation that affects both the shape of the outlet hydrograph and the transport of nutrients and sediments. The widespread adoption of Natural Based Solutions (NBS) practices in the headwaters of these catchments is expected to add additional attenuation primarily through increasing the amount of new storage available to accommodate flood flows. The actual type of NBS features used to add storage could include swales, ditches, and small ponds (acting as sediment traps). Here, recent data collected from monitored features (from the Demonstration Test Catchments project in the Newby Beck catchment (Eden) in northwest England) were used to provide first estimates of the percentages of the suspended sediment (SS) and total phosphorus (TP) loads that could be trapped by additional features. The Catchment Runoff Attenuation Flux Tool (CRAFT) was then used to model this catchment (Newby Beck) to investigate whether adding additional attenuation, along with the ability to trap and retain SS (and attached P), will have any effect on the flood peak and associated peak concentrations of SS and TP. The modelling tested the hypothesis that increasing the amount of new storage (thus adding attenuation capacity) in the catchment will have a beneficial effect. The model results implied that a small decrease of the order of 5–10% in the peak concentrations of SS and TP was observable after adding 2000 m3 to 8000 m3 of additional storage to the catchment.


Author(s):  
Madina M. Khashimova ◽  
Shakhzod F. Turakulov

This article reflects the construction of tourist cities using the resources available on the territory of Uzbekistan. The benefits of utilisation for the development of tourism infrastructure from geological cities that are not exploited, included in the available resources, have been analyzed. The high level of efficiency in the use of geological cities is based on the availability of economic infrastructure, which is recognized as the application of this infrastructure in the construction of tourist cities is low in costs. The article shows the specific natural anchors of three ecotouristic objects, the srategic plans for effective use of these anchors. Proposals on the expediency of the establishment of camps, bags, summer recreation zones are included in these facilities. The abundance of excursion facilities and attractions in the objects of ecotourism expressed their views on the possibility of opening remarkable travel destinations. And the steep slopes of the mountain are shown to be a special training area for training highly qualified climbers. Reflecting the peculiarities of the nature of the objects of the ecosystem, the role of these settlements with unique natural conditions in the development of tourism is established. The potential for the construction of such ecotouristic cities in the Republic of Uzbekistan is high, and the growth in the efficiency of the use of such potentials is reported to increase the number of tourists coming from foreign countries to Uzbekistan.


Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 4095-4103 ◽  
Author(s):  
P.A. Lawrence ◽  
B. Sanson ◽  
J.P. Vincent

Recent experiments on the wing disc of Drosophila have shown that cells at the interface between the anterior and posterior compartments drive pattern formation by becoming the source of a morphogen. Here we ask whether this model applies to the ventral embryonic epidermis. First, we show that interfaces between posterior (engrailed ON) and anterior (engrailed OFF) cells are required for pattern formation. Second, we provide evidence that Wingless could play the role of the morphogen, at least within part of the segmental pattern. We looked at the cuticular structures that develop after different levels of uniform Wingless activity are added back to unsegmented embryos (wingless- engrailed-). Because it is rich in landmarks, the T1 segment is a good region to analyse. There, we find that the cuticle formed depends on the amount of added Wingless activity. For example, a high concentration of Wingless gives the cuticle elements normally found near the top of the presumed gradient. Unsegmented embryos are much shorter than wild type. If Wingless activity is added in stripes, the embryos are longer than if it is added uniformly. We suggest that the Wingless gradient landscape affects the size of the embryo, so that steep slopes would allow cells to survive and divide, while an even distribution of morphogen would promote cell death. Supporting the hypothesis that Wingless acts as a morphogen, we find that these stripes affect, at a distance, the type of cuticle formed and the planar polarity of the cells.


2020 ◽  
Vol 29 (3) ◽  
pp. 229-248 ◽  
Author(s):  
Anna Ribas ◽  
Jorge Olcina ◽  
David Sauri

Purpose The purpose of this paper is to examine the role of high intensity precipitation events in increasing the vulnerability to floods in Mediterranean Spain. Precipitation intensity in this area appears to have augmented in the last two decades in association with warming trends of the Mediterranean Sea. At the same time, intense urbanization processes, occupying and transforming flood prone land, have produced an important increase in exposure. The main objective is to assess whether higher intensity precipitation and changing patterns in exposure aggravate vulnerability to floods. Design/methodology/approach In this paper, vulnerability is understood as the result of the interrelationships between exposure, sensitivity, impacts and adaptive capacity. Consequently, methods used involved the compilation and analysis of published and unpublished precipitation data, population and land use data, data on insurance claims, and media sources related to those variables. Findings Changes toward episodes of more intense precipitation in the expanding urban areas of Mediterranean Spain increase exposure but not necessarily vulnerability, at least in terms of human deaths. However, adaptative capacity needs to be formulated. Actions that attempt to absorb and eventually reuse flood flows (as the flood park in Alicante) appear to be more effective than traditional hydraulic solutions (as in Majorca). Originality/value The paper provides a systematic and coherent approach to vulnerability analysis taking into account the changing dynamics of its components. Especially, it signals the limits of current adaptive approaches to flooding and advocates for changes toward a more circular and less linear approach to urban drainage.


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