• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.187-197
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• 2006

A mathematical modeling program called Hydrological Simulation Program-FORTRAN (HSPF) developed by the United States Environmental Protection Agency(EPA) was applied to the Yongdam Watershed to examine its applicability for loading estimates in watershed scale. It was run under BASINS (Better Assessment Science for Integrating point and Nonpoint Sources) program, and the model was validated using monitoring data of 2002 ${\sim}$ 2003. The model efficiency of runoff was high in comparison between simulated and observed data, while it was relatively low in the water quality parameters. But its reliability and performance were within the expectation considering complexity of the watershed and pollutant sources and land uses intermixed in the watershed. The estimated pollutant load from Yongdam watershed for BOD, T-N and T-P was 1,290,804 kg $yr{-1}$, 3,753,750 kg $yr{-1}$ and 77,404 kg $yr{-1}$,respectively. Non-point source (NPS) contribution was high showing BOD 57.2%, T-N 92.0% and T-P 60.2% of the total annual loading in the study area. The NPS loading during the monsoon rainy season (June to September) was about 55 ${\sim}$ 72% of total NPS loading, and runoff volume was also in a similar rate (69%). However, water quality was not necessarily high during the rainy season, and showed a decreasing trend with increasing water flow. Overall, the BASINS/HSPF was applied to the Yongdam watershed successfully without difficulty, and it was found that the model could be used conveniently to assess watershed characteristics and to estimate pollutant loading in watershed scale.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.44-54
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• 2010

In this study, a comprehensive exploration and evaluation of washland candidate locations by means of field monitoring as well as spatial analysis in six major river system (Han, Nakdong, Nam, Geum, Youngsan, and Seomjin Rivers). Washland(in other words, river detention basin) is an artificial wetland system which is connected to streams or rivers likely to riverine wetlands. Major purpose of washland creation is to control floodings, water supply and purification, providence of eco-cultural space to human and natural populations. Characteristics and functions of riverine wetlands can be expected as well, thus it is believed to be an efficient multi-purpose water body that is artificially created, in terms of hydrology and ecology. Geographical information and field monitoring results for the washland candidate locations were evaluated in 2009, with respect to optimal location exploration, ecosystem connectivity and educational-cultural circumstances. A total of $269\;km^2$ washland candidate locations were found from spatial analysis (main channel of Rivers South Han, 71.5; Nakdong 54.1; Nam, 2.3; Geum, 79.0; Youngsan 46.4; Seomjin 15.7), and they tended to be distributed in mid- to lower part of the rivers to which tributaries are confluent. Field monitoring at 106 sites revealed that some sites located in the Rivers Nam and Geum is appropriate for restoration or artificial creation as riverine wetlands. Several sites in the Nakdong and Seomjin Rivers were close to riverine wetlands (e.g., Upo), habitats of endangered species (e.g., otters), or adjacent to educational facility (e.g., museums) or cultural heritages (e.g., temples). Those sites can be utilized in hydrological, ecological, educational, and cultural ways when evidence of detailed hydrological evaluation is provided. In conclusion, determination of washland locations in the major river basins has to consider habitat expansion as well as hydrological function (i.e. flood control) basically, and further utility (e.g. educational function) will increase the values of washland establishment.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.186-193
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• 2014

This study aimed to analyze spatio-temporal trends of phenological characteristics in South Korea by using MODIS EVI. For the phenology analysis, we had applied double logistic function to MODIS time-series data. Our results showed that starting date of phenology seems to have a tendency along with latitudinal trends. Starting date of phenology of Jeju Island and Mt. Sobeak went back for 0.38, 0.174 days per year, respectively whereas, Mt. Jiri and Mt. Seolak went forward for 0.32 days, 0.239 days and 0.119 days, respectively. Our results exhibited the fluctuation of plant phonological season rather than the change of phonological timing and season. Starting date of plant phenology by spatial distribution revealed tendency that starting date of mountain area was late, and basin and south foot of mountain was fast. In urban ares such as Seoul metropolitan, Masan, Changwon, Milyang, Daegu and Jeju, the phonological starting date went forward quickly. Pheonoligcal attributes such as starting date and leaf fall in urban areas likely being affected from heat island effect and related warming. Our study expressed that local and regional monitoring on phonological events and changes in Korea would be possible through MODIS data.

• Journal of the Korean Geographical Society
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• v.42 no.3 s.120
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• pp.368-387
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• 2007

In order to explain geomorphological characteristics of the Korean Peninsula, it is necessary to understand the spatial distribution of tectonic movements and its causes. Even though geomorphological elements which might have been formed by tectonic movements(e.g. tilted overall landform, erosion surface, river terrace, marine terraces, etc.) have long been considered as main geomorphological research topics in Korea, the knowledge on the spatial distribution of tectonic movement is still limited. This research aims to identify the spatial distributions of tectonic movement via sequential analyses of Digital Elevation Model(DEM). This paper first developed a set of terrain analysis techniques derived from theoretical interrelationships between tectonic uplifts and landsurface denudation processes. The terrain analyses used in this research assume that elevations along major drainage basin divides might preserve original landsurfaces(psuedo-landsuface) that were formed by tectonic movement with relatively little influence by denudation processes. Psuedo-landsurfaces derived from a DEM show clear spatial distribution patterns with distinct directional alignments. Lines connecting psuedo-landsufaces in a certain direction are defined as psuedo-landsurface axes, which are again categorized into two groups: the first is uplift psuedo-landsurface axes that indicate the axis of landmass uplift; and the second is denudational psuedo-landsurface axes that cross step-shaped pusedo-landsurfaces formed via surface denudation. In total, 13 axes of pusedo-landsurface are identified in the Korean Peninsula, which show distinct direction, length, and relative uplift rate. Judging from the distribution of psudo-landsurfaces and their axes, it is concluded that the Korean Peninsula ran be divided into four tectonic regions, which are named as the Northern Tectonic Region, Center Tectonic Region, Southern Tectonic Region, and East Sea Tectonic Region, respectively. The Northern Tectonic Region had experienced a regional uplift centered at the Kaema plateau, and the rate of uplift gradually decreased toward southern, western and eastern directions. The Center Tectonic Region shows an arch-shaped uplift. Its uplift rate is the highest along the East Sea and the rate decreases towards the Yellow sea. The Southern Tectonic Region shows an asymmetric uplift centered a line connecting Dukyu and Jiri Mountains in the middle of the region. The eastern side of the Southern Regions shows higher uplift rate than that of the western side. The East Sea Tectonic Region includes south-eastern coastal area of the peninsula and Gilju-Myeongchun Jigudae, which shows relatively recent tectonic movements in Korea. Since this research visualizes the spatial heterogeneity of long-term tenonic movement in the Korean peninsula, this would provide valuable basic information on long-term and regional differences of geomorphological evolutionary processes and regional geomorphological differences of the Korean Peninsula.

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.233-238
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• 2007

To assess pollutant loads in Nakdong river from highland agriculture in Kyungbuk province we. analyzed water qualities such as BOD, COD, T-N, T-P and SS in year 2005. BOD values in rainy period (June and July) were relatively higher than those in dry period, and those in 4 sites among 17 sites ranged from 10.71-19.25 mg/L which exceeded water criteria (8 mg/L) for agricultural use. COD values showed similar trends like BOD values. These trends might be caused by outflow of nutrients applied in agricultural lands. T-N content ranged from 0.1 to 14 mg/L. Those in lower reaches of stream were greater in those in upper stream. Compared to T-N contents during non-farming season, T-N content in farming season were higher. These phenomenon could be due to continuous input of nutrients from small watercourses. Averaged T-P content in lower stream during farming season was 0.4 mg/L, which was eight times higher than the limiting level for algae occurrence (0.05 mg/L). BOD, T-P, T-N loads from alpine agricultural practices were 12.25 $kg/km^2{\cdot}day$, 0.55 $kg/km^2{\cdot}day$ and 32.35 $kg/km^2{\cdot}day$, respectively. These values were greater than those from forestry. Therefore, Best management Practices (BMP) for alpine agricultural field are needed to reduce pollutant loads in Nakdong river.

• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.41-49
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• 2009

This research conducted a survey on the feeding crane's size, formation and distribution distance subsequent to road pattern and feeding flock's size during the wintering season eight times at the Cheolwon basin in Korea from December 2005 until February 2006. The survey results are as follows: First, the feeding flocks of the Red-crowned and White-naped Crane were found to mainly consist of two to four individuals. Mono-specific feeding flocks were more identified than hetero-specific feeding flocks in both Red-crowned and White-naped Cranes. There existed a significant difference in the ratio by size between the feeding Red-crowned and White-naped Cranes. The crane's average distribution distance from the paved road was much farther than from the unpaved road, paved farm road and unpaved farm road. In case of the white-naped crane, there was a difference in its distance length from between the road and farm road and there existed a significant difference only in the paved road in the distance length by road pattern between these two bird species[Red-crowned and White-naped Crane]. Such a result indicates that crane species don't prefer the road with frequent vehicular traffic to the road with low vehicular traffic. 5 or more individuals of feeding flocks of the Red-crowned Crane were located at a farther distance length from the paved road comparing to less than 5 individuals of the whole feeding flocks and less than 5 individual feeding flocks. 5 or more individuals of feeding flocks of the White-naped Crane were located at a farther distance length from the paved road, paved farm road and unpaved farm road than less than 5 individuals of feeding flocks of the White-naped Crane; however, there existed no difference in distance length subsequent to their group size. Conclusively, it was found out that the flocks with a larger size were more greatly affected by interrupting factors. Considering such results, there seems to be a more relation to the fact that larger size feeding flocks of crane species have a higher efficiency in the lookout for their surroundings.

• The Journal of the Petrological Society of Korea
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• v.14 no.1
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• pp.12-23
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• 2005

Cretaceous granitic rocks in the Waryongsan area occur as a stock and show compositional changes with altitude. They include mafic microgranular enclaves (MME) with various sizes and types. The MMEs present clear evidence of magma mingling such as supercooling zone, mantling texture and back veining. The granitic rocks are divided into porphyritic granite, porphyritic granodiorite and fined-grained granite by their petrographic characteristics and modal compositions. The MMEs are discriminated to quartzdioritie, quartzmonzodiorite and tonalite. They have varying areal proportions in each granitic rock-type: 10∼l5% in the porphyritic granite, about 50% in the porphyritic granodiorite, and about 20% in the fined-grained granite. SiO₂ contents shows compositional change of 61.2∼72.0wt.%. Mean SiO₂ contents have 61.7wt.% in the porphyritic granodiorite, 68.6wt.% in the porphyritic granite. and 71.9wt.% in the fined-grained granite, respectively. Major oxide contents of the granitic rocks linearly vary with SiO₂ contents from the porphyiritic granodiorite to the fine-grained granite on Harker diagrams. Linear compositional variations seem to have been caused by differential degrees of mingling between mafic magma and host granite. Where larger amount of mafic magma was injected into the host granitic magma, the two magmas reached to thermal equilibrium more quickly and eventually chemical mixing occurred to produce the composition of the porphyritic granodiorite. On the other hand. less amount of injected mafic magma would have been responsible for mechanical mixing to produce the compositions of the porphyritic granite and the fined-grained granite. Therefore, it is considered that the granitic rocks in the Waryongsan area experienced magmas mingling resulting from the injection of more mafic magma into differentiating granitic magma, and that the compositional changes of the granitic rocks were ascribed to the degree of mingling between the two magmas.

• The Journal of the Petrological Society of Korea
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• v.22 no.1
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• pp.49-62
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• 2013

The Dongmakgol Tuff is divided into 8 lithofacies based on their grain size and depositional structures: massive tuff breccia(TBm), welded tuff and lapilli tuff(LTw), rheomorphic tuff and lapilli tuff(LTr), massive lapilli tuff(LTm), stratified lapilli tuff(LTs), gradedly bedded lapilli tuff(LTg), crudely bedded lapilli tuff(LTb) and massive fine tuff(Tm). They can be divided into 3 pyroclastic rock group based on their constituents of the lithofacies. The lower group(LI) is composed of LTm, LTw and LTr, which are interpreted to have resulted from emplacement of voluminous pyroclastic flows due to ignimbrite-form eruption to boiling-over eruption. The middle group(LT+MI) consists of LTs, LTg and LTm associated with Tm in the lower part, and of LTm, LTw and LTr in the middle and upper parts; these suggest that started with deposition of pyroclastic surges from phreatoplinian eruption by poor eternal water, passed through emplacement of pyroclastic flows from ignimbrite-form eruption and ended with deposition of voluminous pyroclastic flows from boiling-over eruption. The upper group(lUT+uUT+UI) is composed of LTs, LTg and Tm in the lowermost, TBm, LTb, LTb and Tm in the lower part, and LTm and LTw in the middle and upper part, suggesting that began with deposition of surges from phreatoplinian eruption, passed through deposition of pumice- and ash-fallouts from plinian eruption and transformed into emplacement of pyroclastic flows due to boiling-over eruption. As result, eruptive processes in the Dongmakgol Tuff approximately began with phreatoplinian or/and plinian eruption, transformed into ignimbrite-forming eruption and proceeded into boiling-over eruption in each volcanism, but proceeded presumably without phreatoplinian or plinian eruption in the earlier stage of 1st volcanism.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.281-291
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• 2014

In March to August 2013, the emission of gases ($CH_4$, VOC, $CO_2$, $O_2$, and LEL) was measured three times from the intertidal flat sediments at Sogeun-ri, Taean-gun, in the Mid-western seashore of Korea by using chamber method. After analyzing gas emission concentrations inside of flux enclosure chamber by using a GC equipped with Agilent 6890. The gas emission fluxes were calculated from a linear regression of the changes in the concentrations with time. The ranges of gas flux during the experimental period were $+0.06{\sim}+0.60mg/m^2/hr$ for $CH_4$, $+58.45{\sim}+95.58mg/m^2/hr$ for $CO_2$, $-0.02{\sim}-0.20mg/m^2/hr$ for $O_2$, and $-0.60{\sim}+0.65mg/m^2/hr$ for VOC, respectively. The flux measurement results revealed that $CH_4$ fluxes during March in the relatively low sediment temperature ($14.5^{\circ}C$) were significantly higher ($+0.60mg/m^2/hr$) than during June and August ($+0.06{\sim}+0.18mg/m^2/hr$) in high sediment temperature ($32.0{\sim}36.8^{\circ}C$). $CH_4$ flux to mean size of sediments and temperature of inner chamber exhibited strong positive correlation ($R^2=-0.97$ and $R^2=-0.89$, respectively).

• Journal of Korea Water Resources Association
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• v.46 no.8
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• pp.833-842
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• 2013

The quantile mapping is utilized to reproduce reliable GCM(Global Climate Model) data by correct systematic biases included in the original data set. This scheme, in general, projects the Cumulative Distribution Function (CDF) of the underlying data set into the target CDF assuming that parameters of target distribution function is stationary. Therefore, the application of stationary quantile mapping for nonstationary long-term time series data of future precipitation scenario computed by GCM can show biased projection. In this research the Nonstationary Quantile Mapping (NSQM) scheme was suggested for bias correction of nonstationary long-term time series data. The proposed scheme uses the statistical parameters with nonstationary long-term trends. The Gamma distribution was assumed for the object and target probability distribution. As the climate change scenario, the 20C3M(baseline scenario) and SRES A2 scenario (projection scenario) of CGCM3.1/T63 model from CCCma (Canadian Centre for Climate modeling and analysis) were utilized. The precipitation data were collected from 10 rain gauge stations in the Han-river basin. In order to consider seasonal characteristics, the study was performed separately for the flood (June~October) and nonflood (November~May) seasons. The periods for baseline and projection scenario were set as 1973~2000 and 2011~2100, respectively. This study evaluated the performance of NSQM by experimenting various ways of setting parameters of target distribution. The projection scenarios were shown for 3 different periods of FF scenario (Foreseeable Future Scenario, 2011~2040 yr), MF scenario (Mid-term Future Scenario, 2041~2070 yr), LF scenario (Long-term Future Scenario, 2071~2100 yr). The trend test for the annual precipitation projection using NSQM shows 330.1 mm (25.2%), 564.5 mm (43.1%), and 634.3 mm (48.5%) increase for FF, MF, and LF scenarios, respectively. The application of stationary scheme shows overestimated projection for FF scenario and underestimated projection for LF scenario. This problem could be improved by applying nonstationary quantile mapping.