• Economic and Environmental Geology
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• v.44 no.1
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• pp.83-94
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• 2011

Extra heavy oil reservoirs are distributed over the world but most of them is deposited in the northern part of the Orinoco River in Venezuela, in the area of 5,500 $km^2$, This region, which has been commonly called "the Orinoco Oil Belt", contains estimated 1.3 trillion barrels of original oil-in-place and 250 billion barrels of established reserves. The Venezuela extra heavy oil has an API gravity of less than 10 degree and in situ viscosity of 5,000 cP at reservoir condition. Although the presence of extra heavy oil in the Orinoco Oil Belt has been initially reported in the 1930's, the commercial development using in situ cold production started in the 1990's. The Orinoco heavy oil deposits are clustered into 4 development areas, Boyaco, Junin, Ayachoco, and Carabobo respectively, and they are subdivided into totally 31 production blocks. Nowadays, PDVSA (Petr$\'{o}$leos de Venzuela, S.A.) makes a development of each production block with the international oil companies from more than 20 countries forming a international joint-venture company. The Eastern Venezuela Basin, the Orinoco Oil Belt is included in, is one of the major oil-bearing sedimentary basins in Venezuela and is first formed as a passive margin basin by the Jurassic tectonic plate motion. The major source rock of heavy oil is the late Cretaceous calcareous shale in the central Eastern Venezuela Basin. Hydrocarbon materials migrated an average of 150 km up dip to the southern margin of the basin. During the migration, lighter fractions in the hydrocarbon were removed by biodegradation and the oil changed into heavy and/or extra heavy oil. Miocene Oficina Formation, the main extra heavy oil reservoir, is the unconsolidated sand and shale alternation formed in fluvial-estuarine environment and also has irregularly a large number of the Cenozoic faults induced by basin subsidence and tectonics. Because Oficina Formation has not only complex lithology distribution but also irregular geology structure, geological evolution and characteristics of the reservoirs have to be determined for economical production well design and effective oil recovery. This study introduces geological formation and evolution of the Venezuela extra heavy oil reservoirs and suggest their significant geological characteristics which are (1) thickness and geometry of reservoir pay sands, (2) continuity and thickness of mud beds, (3) geometry of faults, (4) depth and geothermal character of reservoir, (5) in-situ stress field of reservoir, and (6) chemical composition of extra heavy oil. Newly developed exploration techniques, such as 3-D seismic survey and LWD (logging while drilling), can be expected as powerful methods to recognize the geological reservoir characteristics in the Orinoco Oil Belt.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.163-172
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• 2007

In this study, fish fauna and stream characteristics were surveyed during October-November 2003 in 31 small streams, which are small sub-tributaries of Geum River. The small streams were classified into 4 types of steep mountainous (SM), mountainous-flatland (MF), flat land (FL), and agricultural watercourse (AW) streams, and their types were categorized by features of stream width, water depth, bottom substrate, riparian vegetation, and landuse patterns. The fishes collected during this survey were identified 4 families and 8 species. Dominant family was Cyprinidae, and the most dominant species was Rhynchocypris oxycephalus with 73% (419 individuals) of the total. Only one species of R. oxycephalus was observed in the all five steep mountainous streams, which was surrounded by 100% forest area and had no point-and non-point pollution sources. The observed frequency of R. oxycephalus (as a relative proportion of species) showed a significant positive correlation (r=0.754, p<0.001, n=31) with the substrate composition of bedrock and boulder, indicating that the species prefer the bedrock and boulder rather than the sand or small pebble. Evidently, all five steep mountainous streams were judged as excellent condition (1st rank) according to the criteria of biological water quality, the Ministry of Environment, Korea. This result was accord with a general tendency of the species in most upper stream of the Koreas streams. One family and one species were found at the steep mountainous types and 4 families 6 species were at the mountainous-flatland. Four families 8 species were found at the flat land, which showed most diverse habitat, and 2 families 2 species were collected agricultural watercourse. These study results of 1st-order streams suggest that R. oxycephalus was considered as one of 1st rank ecological indicator species, and that the dominant area should be protected from various pollutions and disturbances.

• Land and Housing Review
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• v.5 no.1
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• pp.53-56
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• 2014

Hong Kong, a well-known metropolis characterized by skyscrapers on both sides of the Victoria Harbour, consists mainly of 3 parts, namely the Hong Kong Island, the Kowloon peninsula and the New Territories (N.T.) which is the land area north of Kowloon plus a number of outlying islands. Located in the N.T. are all the new towns, market towns; and in the plains and valleys lie scattered village houses of not more than 3 storeys within the confines of well-defined village. These village houses are governed by a rural housing policy that could be traced back to the very beginning of the former British administration in the N.T. By the Convention of Peking of 1898, the N.T., comprising the massive land area north of Kowloon up to Shenzhen River and 235 islands, was leased to Britain by China for 99 years from 1st July 1898. Soon after occupation, the colonial government conducted a survey of this uncharted territory from 1899 to 1903, and set up a land court to facilitate all land registration work and to resolve disputed claims. By 1905, the Block Crown Leases with Schedule of Lessees and details of the lots, each with a copy of the lot index plan (Demarcation Plan) were executed. Based on the above, Crown rent rolls were prepared for record and rent collection purposes. All grants of land thereafter are known as New Grant lots. After completion and execution of the Block Crown Lease in 1905, N.T. villagers had to purchase village house lots by means of Restricted Village Auctions; and Building Licences were issued to convert private agricultural land for building purposes but gradually replaced by Land Exchanges (i.e. to surrender agricultural land for the re-grant of building land) from the early 1960's until introduction of the current Small House Policy in October 1972. It was not until the current New Territories Small House Policy came into effect in December 1972 that the Land Authority can make direct grant of government land or approve the conversion of self-owned agricultural land to allow indigenous villagers to build houses within the village environs under concessionary terms. Such houses are currently restricted to 700 square feet in area and three storeys with a maximum height of 27 feet. An indigenous villager is a male descendent of a villager who was the resident of a recognized village already existing in 1898. Each villager is only allowed one concessionary grant in his lifetime. Upon return of Hong Kong to the People's Republic of China on July 1st, 1997, the traditional rights of indigenous villagers are protected under Article 40 of the Basic Law (a mini-constitution of the Hong Kong Special Administrative Region). Also all N.T. leases have been extended for 50 years up to 2047. Owing to the escalating demand and spiral landed property prices in recent years, abuse of the N.T. Small House Policy has been reported in some areas and is a concern in some quarters. The Hong Kong Institute of Land Administration attempts to study the history that leads to the current rural housing policy in the New Territories with particular emphasis on the small house policy, hoping that some light can be shed on the "way forward" for such a controversial policy.

• Korean Journal of Plant Resources
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• v.33 no.5
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• pp.516-535
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• 2020

This study was conducted to provide information on local resource plants by identifying aquatic and Riparian flora. We investigated the aquatic and riparian floras in 3 streams(Byeongseong-cheon, Buk-cheon, Oeseo-cheon) from February to October 2019. 321 taxa (i.e. 300 species, 5 subspecies, 15 varieties 1 Cultivars from 203 genera of 78 families) of the vascular plants were found in the survey area. Byeongseong-cheon is 133 taxa, Buk-cheon is 233 taxa and Oeseo-cheon is 132 taxa. Among 321 taxa, we found 5 endemic species, 3 red list plants, and However, endangered plants were not found in 3 streams. Aquatic and Riparian plant 138 taxa(i.e. Aquatic plant 20 taxa, Riparian plant 118 taxa). Life forms is annual plant 43 taxa, biennial plant 24 taxa, perennial plant 71 taxa. Aquatic plant growth forms emergent hydrophyte 13 taxa, floating leaved hydrophyte 1 taxa, submerged hydrophyte 6 taxa. The number of floristic regional indicator plants was 15 (i.e. 1 species of IV degree, 3 taxa of III degree, 5 taxa of II degree, and 6 taxa of I degree). Approved foreign export plants 31 taxa. In addition, 52 naturalized plants were identified, and the percentage of Naturalized Index (NI) and Urbanization Index (UI) were 16.1%, and 16.2%, respectively. Vascular plant usability and reclassification result is Edible 213 species (66%), Medicinal 244 species (76%), Flavor 10 species (3%), Industrial 136 species (42%), Ornamental 137 species (36%), Restoration 117 species (36%), Compost 155 species (48%), Unknown 7 species (5%). We hope that our results provide reference data to set up strategy of resources plants, conservation of biodiversity in the 3 streams and Sangju-si areas.

• Korean Journal of Ecology and Environment
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• v.53 no.3
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• pp.241-254
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• 2020

Three introduced fish species, Japanese white crucian carp (Carassius cuvieri Temminck and Schlegel, 1846), bass (Micropterus salmoides Lacepède, 1802) and bluegill (Lepomis macrochirus Rafinesque, 1819), are dominant fishes in Korean freshwater ecosystem. In this study, we analyzed habitat environment conditions of these three species and their impacts to fish communities in streams across South Korea. Fish community data were obtained from the database of the Stream/River Ecosystem Survey and Health Assessment program maintained by the Ministry of Environment and the National Institute of Environmental Research, Korea. Our results showed that species richness and Shannon diversity of fish were higher at the presence sites of introduced fish than at the absence sites. However, when the abundance of these introduced fish species was increased, the species richness and abundance of fish were decreased. An association analysis showed that the introduced fish species had a low similarity in their appearance with some indigenous fishes such as Siniperca scherzeri and Channa argus and some endemic fishes of Korea such as Zacco koreanus, Sarcocheilichthys variegatus wakiyae, and Acheilognathus yamatsutae. In addition, the introduced fish species had a low appearance similarity with a large number of fishes in their association networks. Finally, our results presented that these introduced fish species influenced the negative impacts to the stream fish communities, and they were potential risk factors for fish community in Korean freshwater ecosystem. Therefore, it is necessary that continuous monitoring and establishment of management strategy for introduced fish species to preserve fish resource and biodiversity in the Korean streams.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.340-349
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• 2009

The natural type section of Gap Stream was divided into 7 sites, such as, closed pool, runs, riffle, opened pool, pool, reek-scattered riffle, and Dam-type pool. The ecological characteristics of fish community at each site was examined from April, 2007 to October, 2008. During the survey period, 29 species belonging to 8 families were collected, and Carassius auratus (St. 1), Coreoleuciscus splendidus (St. 3), Acheilognathus lanceolatus (St. 4) and Zacco platypus (St. 2, 5, 6, 7) were characteristic species that represent each habitat. The species of C. auratus preferred physical habitat with sand-bottom pool, moderate depth of 65$\sim$90 cm, and stagnant water. The species of C. splendidus mainly preferred physical habitat with cobbles and pebbles are scattered riffles (St. 3), moderate depth of 65$\sim$90 cm, and flow velocity is 0.14$\sim$0.85 m $sec^{-1}$. It also preferred where concentration of BOD, COD, TN, TP and SS is low and DO's value is high, because the flow velocity is fast. A. lanceolatus preferred where the depth of water is low (3$\sim$44 cm) like an opened pool (St. 4) and the flow velocity is slow (0.01$\sim$0.02 m $sec^{-1}$). Z. platypus dominated in a variety of habitats such as runs (St. 2), pool (St. 5), rock-scattered riffles (St. 6) and D-type pool (St. 7), and it preferred places where flow is abundant and riverbed structure is diverse. On the other hand, 4 individuals of Iksookimia choii appeared at reek-scattered riffles (St. 6). I. choii appeared in this research lived in where the width of river is 24 m, the depth of water is 3$\sim$35 cm and the flow velocity is 0.01$\sim$0.49 m $sec^{-1}$, and riverbed structure was diversely formed with boulder to sand. Also, water temperature, EC, BOD, COD, TN and TP was low, but concentrations of DO and SS were high comparatively. Therefore, it seems that I. choii can live only in physical and chemical environment with similar conditions.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.664-671
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• 2019

This study was conducted to investigate the environmental impact of the construction of the Yeongju Dam, located near the upper stream of the Nakdong River, on benthic macroinvertebrates. The investigation was conducted four times from 2015 to 2016 and the composition of the benthic macroinvertebrate fauna from the four surveyed sites was compared. After the dam construction, the number of benthic macroinvertebrate species decreased and the species composition ratio of the E.P.T taxa(Ephemeroptera, Plecoptera, and Trichoptera) decreased, which favored the previous environment and the large riverbed structure. However, the species composition ratio of the O.C.H taxa (Odonata, Coleoptera, and Hemiptera), which favored the reservoir environment, increased. For the pattern of changes in the functional habitat groups, the proportion of 'Clinger(CL)' taxa decreased and the 'Burrower(BU), Climber(CB), Sprawler(SP), Swimmer(SW)' taxa increased in all surveys after the dam construction. A cluster stability comparison showed that the 'Stability Group II' species of St.2 and St.3 showed a drastic decrease. The average Benthic Macroinvertebrate Index(BMI) of all the survey sites in 2016 was lower than that in 2015. This research confirmed the temporal and spatial changes in the habitat type and community structure of the benthic macroinvertebrates resulting from the dam construction.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.1
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• pp.101-111
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• 2015

Stream restoration projects have become threats to riparian ecosystem in Rep. of korea. Riparian wildlife becomes isolated and the animals are often experience difficulties in crossing riparian corridors. The purposes of this study is to select suitable wildlife passages for wild animals crossing riparian corridors. Maximum entropy model and snow tracking data on embankment in winter seasons were used to develop species distribution models to select suitable wildlife passages for water deer. The analysis suggests the following. Firstly, most significant factors for water deer's habitat in area nearby riparian area are shown to distance to water, age-class, land cover, slope, aspect, digital elevation model, tree density, and distance to road. For the riparian area, significant factors are shown to be land cover, size of riparian area, distance to tributary, and distance to built-up. Secondly, the suitable wildlife passages are recommended to reflect areas of high suitability with Maximum Entropy model in riparian areas and the surrounding areas and moving passages. The selected suitable areas are shown to be areas with low connectivity due to roads and vertical levee although typical habitats for water deer are forest, grassland, and farmland. In addition, the analysis of traces on snow suggests that the water deer make a detour around the artificial structures. In addition, the water deer are shown to make a detour around the fences of roads and embankment around farmland. Lastly, the water deer prefer habitats around riparian areas following tributaries. The method used in this study is expected to provide cost-efficient and functional analysis in selecting suitable areas.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.47-56
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• 2014

Recently, the velocity of sea-level rising has increased due to the global warming and the natural disasters have been occurred many times. Therefore, there are various demands for the integration of vertical reference datums for the ocean and land areas in order to develop a coastal area and prevent a natural disaster. Currently, the vertical datum for the ocean area refers to Local Mean Sea Level(LMSL) and the vertical datum for the land area is based on Incheon Mean Sea Level(IMSL). This study uses 31 points of Tidal Gauge Bench Mark (TGBM) in order to compares and analyzes the geometric heights referring LMSL, IMSL, and the nationally determined geoid surface. 11 points of comparable data are biased more than 10 cm when the geometric heights are compared. It seems to be caused by the inflow of river, the relocation of Tidal Gauge Station, and the topographic change by harbor construction. Also, this study analyze the inclination of sea surface which is the difference between IMSL and LMSL, and it shows the inclination of sea surface increases from the western to southern, and eastern seas. In this study, it is shown that TGBM can be used to integrate vertical datums for the ocean and land areas. In order to integrate the vertical datums, there need more surveying data connecting the ocean to the land area, also cooperation between Korea Hydrographic and Oceanographic Administration and National Geographic Information Institute. It is expected that the integrated vertical datum can be applied to the development of coastal area and the preventative of natural disaster.

• Journal of the Korean Geographical Society
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• v.31 no.2
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• pp.138-159
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• 1996

There has been a tendency for Geomorphology and Climatology to be dominant in Physical Geography for 50 years in Korea. Physical Geography is concerned with the study of the totality of natural environment through the integrated approaches. But, an overall direction or a certain paradigm could not be found, because major sub-divisions of Physical Geography have been studied individually and the subjects and the approaches in studying Physical Geography are enormously diverse. A consensus of opinion could not also exist in deciding what kind of the sub-divisions should be included in the physical geography in general and how those should be summarized. Furthermore it would be considered imprudent to survey the studies of Physical Geography besides those of Geomorphology and Climatology due to the small number of researchers. Assuming that the rest of Physical Geographical studies with the exception of Geomorphological and Climatological studies are the Physical Geography in general, the studies of Physical Geogrpahy in general are summarized and several aspects are drown out as follows. First the descliption of all possible factors of natural environments was the pattern of early studies of Physical Geography and the tendency is maintained in the various kinds of research and project reports. Recently Physical Geographers have published several introductory textbooks or research monographs. In those books, however, the integrated approaches to Physical Geography were not suggested and the relationship between man and nature are dealt with in the elementary level. Second, the authentic soil studies of Physical Geographers are insignificant, because the studies of soil in Physical Geography have been mostly considered as the subsidiary means of Geomorphology Summarizing the studies of Soil Gegraphy by physical geographers and other Pedologists, the subjects are classified as soil-forming processes, soil erosions, soil in the tidal flat and reclaimed land, and soil pollution. Physical Geographers have focused upon the soil-forming processes in order to elucidate the geomorphic processes and the past climatic environment. The results of other subjects are trifling. Thirdy Byogeygrayhers and the results of studies are extremely of small number and the studies of Biogeography in Korea lines in the starting point. But, Biogeography could be a more unifying theme for the Physical-human Geography interface, and it would be expected to play an active part in the field of environmental conservation and resource management. Forth, the studies of Hydrogeography (Geographical Hydrology) in Korea have run through the studies of water balance and the morphometric studies such as the drainage network analysis and the relations of various kinds of morphometric elements in river. Recently, the hydrological model have introduced and developed to predict the flow of sediment, discharge, and ground water. The growth of groundwater studies is worthy of close attention. Finally, the studies on environmental problems was no mole than the general description about environmental destruction, resource development, environmental conservation, etc. until 1970s. The ecological perspectives on the relationship between man and nature were suggested in some studies of natural hazard. The new environmentalism having been introduced since 1980s. Human geographers have lead the studies of Environmental Perception. Environmental Ethics, Environmental Sociology, environmental policy. The Physical geographers have stay out of phase with the climate of the time and concentrate upon the publication of introductory textbooks. Recently, several studies on the human interference and modification of natural environments have been made an attempt in the fields of Geomorphology and climatology. Summarizing the studies of Physical Geography for 50 years in Korea, the integrated approaches inherent in Physical Geography disappeared little by little and the majol sub-divisions of Physical Ceography have develop in connection with the nearby earth sciences such as Geology, Meteorology, Pedology, Biology, Hydrology, etc been rediscovered by non-geographers under the guise of environmental science. It is expected that Physical Geography would revive as the dominant subject to cope with environmental problems, rearming with the innate integrated approaches.