• Animal cells and systems
• /
• v.1 no.2
• /
• pp.259-263
• /
• 1997

Oreurinus cutspidatus Ito, the type species of the monotypic genus oreurinus Ito, is redescribed and illustrated in light of newly discovered male specimens from Korea. In Mt. Gachilbong, a number of males were found sitting on rocks along the mountain stream of deep woods while only a single female was swept from nearby vegetation. Based on morphological data, especially using postabdominal structures, Oreurinus is placed in the Trypeta group of the subtribe Trypetina (Trypetinae: Trypetini).

• Animal Systematics, Evolution and Diversity
• /
• v.33 no.1
• /
• pp.33-36
• /
• 2017

Two new Hydropsychidae (Insecta: Trichoptera) species from the Philippines are described. Hydropsyche philippinensis, n. sp., differs from other congeners in the structure of the phallic apparatus. Diplectrona lagunensis, n. sp., can be distinguished from other congeners by its distinct white band pattern in the forewings and by the structure of the phallus. Both new species were collected from a high mountain stream in the northern part of the Philippines. Paratype materials were barcoded to make the sequences readily available in the GenBank.

• Animal cells and systems
• /
• v.11 no.2
• /
• pp.125-128
• /
• 2007

A new perlid stonefly, Chinoperla rhododendrona n. sp., is described from a tropical mountain stream in central Vietnam. The male adult of this species can be characterized by the strongly setous body and unique L-shaped genital structure. The female adult can be distinguished by the posteromedially sclerotized and widely notched subgenital plate. The egg is unique among its congeners as it has smooth chorion and long and narrow collar. Illustrations of diagnostic characters are provided.

• Journal of The Geomorphological Association of Korea
• /
• v.27 no.3
• /
• pp.41-51
• /
• 2020

This study tried to reveal incision rate distribution of streams on the northern part of the Sobaek Mountain Range with OSL age dating and geomorphic analysis, and factors influencing on the distribution were also discussed. With results from the previous studies, a total of 10 sites from 7 streams in the study area showed the rates ranging from 0.220 m/ka to 0.297 m/ka. Namhan-gang and Geum-cheon indicated the highest and lowest rates, respectively. Both sides in the northern section in the study area showed similar rates, while the western side in the middle section and the eastern side in the southern section showed higher rates than the other sides. Higher rates were also found from the eastern and northern sides where the Range runs N-S and E-W directions, respectively. Certain relationships with altitude and distance from the divide can be recognized from the rates and may be attributed to active incision with altitude and location of the uplift axis near the present divide. The rates on granite and sedimentary rock were higher than those on metamorphic rock, indicating that bedrock type is one of the important factors influencing on stream incision. Tectonic movement seemed to play some roles in the rates, because areas with lineaments showed lower rates. This study suggests that incision rate distribution of streams on the northern part of the Sobaek Mountain Range reflects various local geomorphic and geologic conditions.

• Korean Journal of Ecology and Environment
• /
• v.48 no.4
• /
• pp.280-286
• /
• 2015

Life cycles of Sweltsa illiesi and S. lepnevae were determined from a headwater stream in Mt. Jumbong. Identification of nymphs was done by using DNA barcoding. Nymphs begin to have species specific color pattern on their head several months prior to adult emergence and differ in the form of the third antennal segment. Two species appear to have similar semivoltine life cycles in this stream, beginning to hatch from June and finishing adult emergence about 701 days later. The combined annual mean biomass in ash free dry mass (AFDM) was estimated as $96mg\;AFDM\;m^{-2}$. The combined annual secondary production were 373 mg and $297mg\;AFDM\;m^{-2}\;yr^{-1}$, calculated by using size frequency method and increment summation method respectively.

• Journal of The Geomorphological Association of Korea
• /
• v.17 no.2
• /
• pp.1-13
• /
• 2010

The technique of mountain ordering developed by Yamada(1999) has been tested to two small islands (Namhaedo: 301km², Geojedo: 378km²). The results and experiences above were extended and applied to the whole area of the southern part of Korean Peninsula. Three areas such as Seorak-Taebaek Mountains, Jiri-Deogyu Mountains, and Youngnam Alps are identified as the highest, 5th order mountains. 10 areas are classified as the 4th order and 87 areas as the 3rd order. It is suggested that the 5th order mountains are related to the axis of uplift and the 4th and 3rd order mountains have the same direction (NE-SW) as that of the secondary mountain systems in the Korean Peninsula. The logarithmic values of number, area, and relative altitude of the ordered mountains have the linear relationship with the order, as the laws of stream order. The several mountains which are not included in the existing mountain systems could be identified among the ordered mountains, and those mountains could be used as the basis to understand the geological structure of the Korean Peninsula. Most of the National Parks and the Provincial Parks are distributed on the 3rd, 4th, 5th order mountains. It is especially confirmed that the Songnisan National Park take a role to link the Seorak-Taebaek Mountains and Jiri-Deogyu Mountains as a important ecological axis. Therefore, it would be validated that the technique of mountain ordering has the practical values as well as the geomorphological significances.

• Journal of Environmental Science International
• /
• v.21 no.6
• /
• pp.725-738
• /
• 2012

Recently, a variety of GIS-based tools enabling to generate topographic parameters for hydrologic and hydraulic researches have been developed. However, most of GIS-based tools are usually insufficient to estimate and visualize river channel slopes especially along the river network, which can be possibly utilized for many hydraulic equations such as Manning's formula. Many existing GIS-based tools have simply averaged cell-based slopes for the other advanced level of hydrologic units as likely as the mean watershed slope, thus that the river channel slope from the simple approach resulted in the inaccurate channel slope particularly for the mountain region where the slope varies significantly along the downstream direction. The paper aims to provide several more advanced GIS-based methodologies to assess the river channel slopes along the given river network. The developed algorithms were integrated with a newly developed tool named RiverSlope, which adapted theoretical formulas of river hydraulics to calculate channel slopes. For the study area, Han stream in the Jeju island was selected, where the channel slopes have a tendency to rapidly change the upstream near the Halla mountain and sustain the mild slope adjacent to watershed outlet heading for the ocean. The paper compared the simple slope method from the Arc Hydro, with other more complicated methods. The results are discussed to decide better approaches based on the given conditions.

• Korean Journal of Environment and Ecology
• /
• v.18 no.2
• /
• pp.197-204
• /
• 2004

The concept of Baekdudaegan(Korean traditional and major mountain system) was conceived toward the close of Silla Kingdom and in the beginning of the Goryeo dynasty. The concept was brought up through the Goryeo dynasty and was completed in the Joseon dynasty. We have to recognize the next two facts to restore the Baekdudaegan concept these days. Firstly, Baekdudaegan is not the highest watershed line but a domain. Secondly, Baekdudaegan is not a set of ridges but a corporate body of a water system and a mountain system. When it comes to fix the management area of Baekdudaegan, it is necessary to make criteria on the basis of traditional ideas and to include natural characteristics considering physical environment. The management area of Baekdudaegan include the third order of stream with the conservation area including the first order of stream. The most important thing in the management strategy is to prevent the damage of configuration of the ground. Baekdudaegan is a symbol of Korea spirit. Therefore, to manage Baekdudaegan wisely is one of ways to lay down the stepping stone of our country's reunification.

• Journal of Environmental Science International
• /
• v.24 no.4
• /
• pp.371-381
• /
• 2015

In the mountain streams in Jeju Island, strong turbulence and roughness usually made it nearly impossible to utilize most of intrusive instrumentation for streamflow discharge measurements. Instead, a non-intrusive fixed electro-magnetic wave surface velocimetry (fixed EWSV: Kalesto) became alternatively popular in many representative streams to measure stream discharge seamlessly. Currently, Kalesto has shown noteworthy performance with little loss in flood discharge measurements and also has successfully provided discharge for every minute. However, Kalesto has been operated to regard its measured one-point velocity as the representative mean velocity for the given cross-section. Therefore, it could be highly possible to potentially encompass discharge measurements errors. In this study, we analyzed the difference between such Kalesto discharge measurements and other alternative concurrent discharge measurements such as Acoustic Doppler Current Profiler (ADCP) and mobile EWSV which were able to measure velocity in multi-points in the cross-section. Consequently, Kalesto discharge deviated from ADCP discharge in amount of 48% for relatively low flow, and more than 20% difference for high flow compared with mobile EWSV discharge measurements. These results indicated that the one-point velocity measured by Kalesto should be used as a cross-sectional mean velocity, rather it should be accounted for as an index-velocity in conjunction with directly measured cross-sectional mean velocity by using more reliable instrumentations. After inducing Kalesto Discharge Correction Coefficient (KDCC) that actually means relationship between index velocity and cross-sectional mean velocity, the corrected discharge from Kalesto was significantly improved. Therefore, we found that index velocity method should be applied to obtain better accuracy of discharge measurement in case of Kalesto operation.

• Journal of Korean Society of Forest Science
• /
• v.100 no.2
• /
• pp.202-211
• /
• 2011

The geometric characteristics of step-pool structures and how they are influenced by channel characteristics were investigated in a steep mountain stream in the Experimental Forests of Kangwon National University in Chuncheon, Gangwon-do. Average values of steps for the study reaches were as follows: step spacing, 4.69 m; step height, 0.47 m; step drop, 0.71 m; step-forming particle sizes, 0.68 m; number, 21steps/ 100 m; the ratio of step spacing to channel width, 0.5; and step steepness, 0.13. Relationships between spacing and height of steps and channel gradient showed a negative- and positive correlation, respectively, whereas all geometric variables of steps manifested poor correlation with channel width. Therefore, step steepness, expressed as the ratio of step height to step spacing, increased as channel gradient increased. The ratio of step steepness to channel gradient representing the criterion of maximum flow resistance was 1.2, indicating the channel bed's stable condition. In particular, the relationship between the ratio of step drop to step height and channel gradient showed a significant negative correlation, suggesting the influence of step-pool geometry in trapping sediment and providing an aquatic habitat. Positive correlations also exist between spacing and drop of steps and step particles. Our findings suggest that the dynamics of step-pool structures may strongly control physical and ecological environments in steep mountain streams, so understanding them is essential for stream management.