• Title/Summary/Keyword: hydrological geography

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Spatial and Temporal Characteristics of Water Quality in the Wangsook River and Water Environmental Management (왕숙천 수질의 시${\cdot}$공간적 특성과 유역의 물환경 관리)

  • Park, Jong-Kwan
    • Journal of the Korean Geographical Society
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    • v.32 no.4
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    • pp.445-462
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    • 1997
  • This study was conducted to analyze the spatial and temporal characteristics of stream water quality and to charify the management of watershed environment from the standpoint of hydrological geography. To achieve the purpose of the study, the Wangsook River was chosen. As the result of this study, the specific conclusions were drawn. 1. In general, WT(water temperature) of the downstream is higher than that of the upstream. The value of winter WT measured in densely populated area is higher than that measured under the natural conditions. The seasonal variation of WT at upstream sites is greater than that of downstream. 2. Rhe water quality of main channel is dependent on that of tributaries. Especially, the values of pH, EC, TDS in main channel depend upon those of tributaries. Among the tributaries of the Wangsook river, the Jingun-chon and Yongam-chon have mostly influence on the water quality of the main channel. 3. Generally, the values of COD measured in the Wangsook River are over the 5th Grade considering from a point of water quality standards of inland lake. However, BOD, phosphorus and nitrogen concentrations have to be measured to clear the water quality conditions of the river. 4. The regional people who live in the catchment of Wangsook river have different perception about the water pollution of the river. The regional people lacks in the understanding of the Wangsook river cause a bad influence upon the hydrological management of watershed environment.

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The Influence of the Infinitive Flow Direction Algorithm and Horn Slope Algorithm on the Topographic Index and Hydrological Responses of the TOPMODEL (무한 유향 알고리듬과 Horn 경사 알고리듬이 TOPMODEL 지형지수와 수문반응에 미치는 영향)

  • Byun, Jong-Min;Kim, Jong-Wook
    • Journal of the Korean Geographical Society
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    • v.44 no.3
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    • pp.207-223
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    • 2009
  • The TOPMODEL Topographic Index (TI) is widely used to predict the spatial distribution of soil moisture contents, The TI is one of terrain indices which are frequently used in spatially distributed environmental modelings. There have been studies on the evaluation and improvement of the TI. Most of them. however, have focused on only the modified multiple flow direction algorithm and algorithms for slope calculation have been paid little attention, In this research, we attempted to improve the TI by utilizing the infinitive flow direction (Dinf) algorithm and Horn slope algorithm. Then we attempt to analyze and evaluate the influence of the improved TI on hydrological responses of the TOPMODEL As a result. our approaching using the infinitive flow direction (Dinf) and Horn slope algorithm made the TI better than the multiple flow direction (MD8) - the multiple descent slope (MDS) algorithm. However, the model efficiency of discharges at the outlet was not increased. Our research may provide an insight to choose appropriate algorithms for calculating flow direction and slope in spatially distributed environmental modelings.

The physical geography in general:yesterday and tomorrow (자연지리학 일반: 회고와 전망)

  • Son, Ill
    • 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.

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The Variation of Hydro-Geomorphological Environment in Baekgok Wetland due to Water-Level Fluctuation of Reservoir (댐 수위 변동에 따른 백곡습지의 수문지형 환경 변화)

  • Kim, Dong Hyun;Park, Jongkwan
    • Journal of The Geomorphological Association of Korea
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    • v.24 no.1
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    • pp.39-50
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    • 2017
  • This study was conducted to analyze the variation of hydro-geomorphological environment along Baekgok wetland, which experiencing periodical inundation, in that water-level fluctuation of reservoir caused by irrigation. Since the field data is unavailable, modeling techniques, involving models such as HSPF and TELEMAC-2D, have been applied to simulate hydrological cycle in watershed and hydrodynamics in channel scale. The result of simulation indicates that the water-level of reservoir determines both the water surface extension and water depth in the wetland. Furthermore, it also shows that water-level functions as a spatial limit factor for a fluvial environment and woody vegetation such as willow. The fact of which the scale of water-level fluctuation being larger than an average topographical relief along the wetland can explain the result. While the water-level kept high, the wetland is submerged and waterbody becomes lentic. In contrast, while the water-level is lowered, fluvial phenomena of which being dependent on flow rate and channel shape become active. Hence, the valid fluvial process is likely to take place only for 4 months annually just near the channel, and it advances to a conclusion expecting a deposition to be dominant among the wetland except for such area. It is anticipated that such understanding can contribute to establishing plans to preserve the geomorphological and ecological value of the Baekgok wetland.

Study on Climate Change Impacts on Hydrological Response using a SWAT model in the Xe Bang Fai River Basin, Lao People's Democratic Republic (기후변화에 따른 라오스인민공화국의 시방파이 유역의 수문현상 예측에 대한 연구: SWAT 모델을 이용하여)

  • Phomsouvanh, Virasith;Phetpaseuth, Vannaphone;Park, Soo Jin
    • Journal of the Korean Geographical Society
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    • v.51 no.6
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    • pp.779-797
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    • 2016
  • A calibrated hydrological model is a useful tool for quantifying the impacts of the climate variations and land use/land cover changes on sediment load, water quality and runoff. In the rainy season each year, the Xe Bang Fai river basin is provisionally flooded because of typhoons, the frequency and intensity of which are sensitive to ongoing climate change. Severe heavy rainfall has continuously occurred in this basin area, often causing severe floods at downstream of the Xe Bang Fai river basin. The main purpose of this study is to investigate the climate change impact on river discharge using a Soil and Water Assessment Tool (SWAT) model based on future climate change scenarios. In this study, the simulation of hydrological river discharge is used by SWAT model, covering a total area of $10,064km^2$ in the central part of country. The hydrological model (baseline) is calibrated and validated for two periods: 2001-2005 and 2006-2010, respectively. The monthly simulation outcomes during the calibration and validation model are good results with $R^2$ > 0.9 and ENS > 0.9. Because of ongoing climate change, three climate models (IPSL CM5A-MR 2030, GISS E2-R-CC 2030 and GFDL CM3 2030) indicate that the rainfall in this area is likely to increase up to 10% during the summer monsoon season in the near future, year 2030. As a result of these precipitation increases, the SWAT model predicts rainy season (Jul-Aug-Sep) river discharge at the Xebangfai@bridge station will be about $800m^3/s$ larger than the present. This calibrated model is expected to contribute for preventing flood disaster risk and sustainable development of Laos

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Distribution of Stream Incision Rates in the Northern Part of the Taebaek Mountains (태백 산지 북부의 하천 하각률 분포)

  • Lee, Gwang-Ryul
    • Journal of The Geomorphological Association of Korea
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    • v.25 no.4
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    • pp.1-19
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    • 2018
  • This study tries to identify distributional characteristics of stream incision rates at 23 points in the northern part of the Taebaek Mountains. Soyang-gang, Naerin-cheon, Odae-cheon, Dong-gang and upper reaches of Okdong-cheon Rivers closed to the Range show higher incision rates and the rates clearly decrease with distance from the Range. Therefore, the incision process in the northern part of the Range has been greatly influenced by uplift around the Range, and the Sobaek Mountain Range seem to play a role in the incision process. Limestone areas show lower incision rates due to degradation of terrace surface by dissolution. This study suggests that local hydrological, geological and geomorphological conditions can be regarded as an important factor in stream incision rates, although stream incision rates are greatly influenced by regional uplift.

Hydrological Properties of the Water Spider Habitat in Yeoncheon (연천 은대리 물거미 서식지의 수문적 특성)

  • Yang, Jae-Hyuk
    • Journal of The Geomorphological Association of Korea
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    • v.26 no.1
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    • pp.107-119
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    • 2019
  • In recent years, the drying of the water spider habitat has been progressing rapidly. This is the primary cause of extreme climatic events in 2014/2015 with overall reduction in annual precipitation, but impermeable clayey layer formed in the superficial formation also plays an important role. The clayey layer is a critical factor in the formation of wetlands on a well-drained lava plateau, but paradoxically, it restricts the connection with ground water, increasing the instability of the water balance and making it precipitation-dependent structure. In addition, construction of roads/drainways has also caused drying of wetlands by blocking or rapidly spilling surface water/sheet flow. Therefore, to keep the wetlands sustainable, it should increase the flow into the wetlands by removing the road/drainways and floodgates installed to reduce the outflow.

Future Korean Water Resources Projection Considering Uncertainty of GCMs and Hydrological Models (GCM과 수문모형의 불확실성을 고려한 기후변화에 따른 한반도 미래 수자원 전망)

  • Bae, Deg-Hyo;Jung, Il-Won;Lee, Byung-Ju;Lee, Moon-Hwan
    • Journal of Korea Water Resources Association
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    • v.44 no.5
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    • pp.389-406
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    • 2011
  • The objective of this study is to examine the climate change impact assessment on Korean water resources considering the uncertainties of Global Climate Models (GCMs) and hydrological models. The 3 different emission scenarios (A2, A1B, B1) and 13 GCMs' results are used to consider the uncertainties of the emission scenario and GCM, while PRMS, SWAT, and SLURP models are employed to consider the effects of hydrological model structures and potential evapotranspiration (PET) computation methods. The 312 ensemble results are provided to 109 mid-size sub-basins over South Korean and Gaussian kernel density functions obtained from their ensemble results are suggested with the ensemble mean and their variabilities of the results. It shows that the summer and winter runoffs are expected to be increased and spring runoff to be decreased for the future 3 periods relative to past 30-year reference period. It also provides that annual average runoff increased over all sub-basins, but the increases in the northern basins including Han River basin are greater than those in the southern basins. Due to the reason that the increase in annual average runoff is mainly caused by the increase in summer runoff and consequently the seasonal runoff variations according to climate change would be severe, the climate change impact on Korean water resources could intensify the difficulties to water resources conservation and management. On the other hand, as regards to the uncertainties, the highest and lowest ones are in winter and summer seasons, respectively.

Optimization of PRISM Parameters and Digital Elevation Model Resolution for Estimating the Spatial Distribution of Precipitation in South Korea (남한 강수량 분포 추정을 위한 PRISM 매개변수 및 수치표고모형 최적화)

  • Park, Jong-Chul;Jung, Il-Won;Chang, Hee-Jun;Kim, Man-Kyu
    • Journal of the Korean Association of Geographic Information Studies
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    • v.15 no.3
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    • pp.36-51
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    • 2012
  • The demand for a climatological dataset with a regular spaced grid is increasing in diverse fields such as ecological and hydrological modeling as well as regional climate impact studies. PRISM(Precipitation-Elevation Regressions on Independent Slopes Model) is a useful method to estimate high-altitude precipitation. However, it is not well discussed over the optimization of PRISM parameters and DEM(Digital Elevation Model) resolution in South Korea. This study developed the PRISM and then optimized parameters of the model and DEM resolution for producing a gridded annual average precipitation data of South Korea with 1km spatial resolution during the period 2000-2005. SCE-UA (Shuffled Complex Evolution-University of Arizona) method employed for the optimization. In addition, sensitivity analysis investigates the change in the model output with respect to the parameter and the DEM spatial resolution variations. The study result shows that maximum radius within which station search will be conducted is 67km. Minimum radius within which all stations are included is 31km. Minimum number of stations required for cell precipitation and elevation regression calculation is four. Optimizing DEM resolution is $1{\times}1km$. This study also shows that the PRISM output very sensitive to DEM spatial resolution variations. This study contributes to improving the accuracy of PRISM technique as it applies to South Korea.