• Title/Summary/Keyword: Watershed Scale

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A Study on Rural Landscape Planning Based on Rural Village Landscape - A Case Study on Yacksan at Wando - (농촌 마을경관을 고려한 지역경관계획 수립 방안 연구 - 완도군 약산권역을 사례로 -)

  • Kim, Seong-Hak;Yang, Byoung-E
    • Journal of the Korean Institute of Landscape Architecture
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    • v.37 no.3
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    • pp.82-90
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    • 2009
  • The aim of this study is to identify the spatial foundation units required to execute a rural village landscape plan. Though there have been various previous studies on spatial foundation units for rural space and landscape elements, they are limited in clarifying the landscape identity of a rural village unit in creating a feasible a rural village landscape plan. Therefore, it is necessary to identify the natural spatial features of a rural village and then establish a landscape identity for each space by exploring the landscape elements for each rural village unit set as the basic unit. Accordingly, the basic spatial unit was analyzed through a 1:5000 scale mapping by applying geomancy theory to the spatial landscape unit in a naturally generated rural village. The spatial limitations for a rural village landscape were set based on the analysis. Afterwards, a field study on the feasibility of whether or not setting a space as the basic unit for landscape could have a sense of identity as a single landscape unit for verification was processed, and the spatial limitations for the landscape were adjusted. Moreover, landscape elements were investigated by classifying landscape resources based on rural amenity resources which have been diversely researched in terms of the set spatial boundaries, and the sense of identity for each landscape foundation unit was looked into. While the numerous preceding studies focused on exploring the rural landscape value and findingout the sense of identity on landscape elements, it is high time for feasible and applicable studies in conducting region-specific landscape plans. In particular, similar outcomes from all landscape plans, even those with the same purpose established in various regions, is not a desirable outcome. Therefore, a basic framework is needed to discover the landscape identity generated by each plan in a rural area space. In this sense, this study is significant in that itcan be utilized to establish spatial identity of each region and landscape features of each rural village, and come up with realistic alternatives in landscape plans for each region by exploring the landscape identity in each specific space divided per watershed in a single zone.

Analysis of the effect of long-term water supply improvement by the installation of sand dams in water scarce areas (물부족 지역에서 샌드댐 설치에 의한 장기 물공급 개선 효과 분석)

  • Chung, Il-Moon;Lee, Jeongwoo;Lee, Jeong Eun;Kim, Il-Hwan
    • Journal of Korea Water Resources Association
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    • v.55 no.12
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    • pp.999-1009
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    • 2022
  • The Chuncheon Mullori area is an underprivileged area for water welfare that does not have a local water supply system. Here, water is supplied to the village by using a small-scale water supply facility that uses underground water and underground water as the source. To solve the problem of water shortage during drought and to prepare for the increasing water demand, a sand dam was installed near the valley river, and this facility has been operating since May 2022. In this study, in order to evaluate the reliability of water supply when a sand dam is assumed during a drought in the past, groundwater runoff simulation results using MODFLOW were used to generate inflow data from 2011 to 2020, an unmeasured period. After performing SWAT-K basin hydrologic modeling for the watershed upstream of the existing water intake source and the sand dam, the groundwater runoff was calculated, and the relative ratio of the monthly groundwater runoff for the previous 10 years to the monthly groundwater runoff in 2021 was obtained. By applying this ratio to the 2021 inflow time series data, historical inflow data from 2011 to 2020 were generated. As a result of analyzing the availability of water supply during extreme drought in the past for three cases of demand 20 m3/day, 50 m3/day, and 100 m3/day, it can be confirmed that the reliability of water supply increases with the installation of sand dams. In the case of 100 m3/day, it was analyzed that the reliability exceeded 90% only when the existing water intake source and the sand dam were operated in conjunction. All three operating conditions were evaluated to satisfy 50 m3/day or more of demand based on 95% reliability of water supply and 30 m3/day or more of demand based on 99% of reliability.

Application of Flux Average Discharge Equation to Assess the Submarine Fresh Groundwater Discharge in a Coastal Aquifer (연안 대수층의 해저 담지하수 유출량 산정을 위한 유량 평균 유출량 방정식의 적용)

  • Il Hwan Kim;Min-Gyu Kim;Il-Moon Chung;Gyo-Cheol Jeong;Sunwoo Chang
    • The Journal of Engineering Geology
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    • v.33 no.1
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    • pp.105-119
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    • 2023
  • Water supply is decreasing due to climate change, and coastal and island regions are highly dependent on groundwater, reducing the amount of available water. For sustainable water supply in coastal and island regions, it is necessary to accurately diagnose the current condition and efficiently distribute and manage water. For a precise analysis of the groundwater flow in the coastal island region, submarine fresh groundwater discharge was calculated for the Seongsan basin in the eastern part of Jeju Island. Two methods were used to estimate the thickness of the fresh groundwater. One method employed vertical interpolation of measured electrical conductivity in a multi depth monitoring well; the other used theoretical Ghyben-Herzberg ratio. The value using the Ghyben-Herzberg ratio makes it impossible to accurately estimate the changing salt-saltwater interface, and the value analyzed by electrical conductivity can represent the current state of the freshwater-saltwater interface. Observed parameter was distributed on a virtual grid. The average of submarine fresh groundwater discharge fluxes for the virtual grid was determined as the watershed's representative flux. The submarine fresh groundwater discharge and flux distribution by year were also calculated at the basin scale. The method using electrical conductivity estimated the submarine fresh groundwater discharge from 2018 to 2020 to be 6.27 × 106 m3/year; the method using the Ghyben-Herzberg ratio estimated a discharge of 10.87 × 106 m3/year. The results presented in this study can be used as basis data for policies that determine sustainable water supply by using precise water budget analysis in coastal and island areas.

A Study on the Use of GIS-based Time Series Spatial Data for Streamflow Depletion Assessment (하천 건천화 평가를 위한 GIS 기반의 시계열 공간자료 활용에 관한 연구)

  • YOO, Jae-Hyun;KIM, Kye-Hyun;PARK, Yong-Gil;LEE, Gi-Hun;KIM, Seong-Joon;JUNG, Chung-Gil
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.4
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    • pp.50-63
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    • 2018
  • The rapid urbanization had led to a distortion of natural hydrological cycle system. The change in hydrological cycle structure is causing streamflow depletion, changing the existing use tendency of water resources. To manage such phenomena, a streamflow depletion impact assessment technology to forecast depletion is required. For performing such technology, it is indispensable to build GIS-based spatial data as fundamental data, but there is a shortage of related research. Therefore, this study was conducted to use the use of GIS-based time series spatial data for streamflow depletion assessment. For this study, GIS data over decades of changes on a national scale were constructed, targeting 6 streamflow depletion impact factors (weather, soil depth, forest density, road network, groundwater usage and landuse) and the data were used as the basic data for the operation of continuous hydrologic model. Focusing on these impact factors, the causes for streamflow depletion were analyzed depending on time series. Then, using distributed continuous hydrologic model based DrySAT, annual runoff of each streamflow depletion impact factor was measured and depletion assessment was conducted. As a result, the default value of annual runoff was measured at 977.9mm under the given weather condition without considering other factors. When considering the decrease in soil depth, the increase in forest density, road development, and groundwater usage, along with the change in land use and development, and annual runoff were measured at 1,003.5mm, 942.1mm, 961.9mm, 915.5mm, and 1003.7mm, respectively. The results showed that the major causes of the streaflow depletion were lowered soil depth to decrease the infiltration volume and surface runoff thereby decreasing streamflow; the increased forest density to decrease surface runoff; the increased road network to decrease the sub-surface flow; the increased groundwater use from undiscriminated development to decrease the baseflow; increased impervious areas to increase surface runoff. Also, each standard watershed depending on the grade of depletion was indicated, based on the definition of streamflow depletion and the range of grade. Considering the weather, the decrease in soil depth, the increase in forest density, road development, and groundwater usage, and the change in land use and development, the grade of depletion were 2.1, 2.2, 2.5, 2.3, 2.8, 2.2, respectively. Among the five streamflow depletion impact factors except rainfall condition, the change in groundwater usage showed the biggest influence on depletion, followed by the change in forest density, road construction, land use, and soil depth. In conclusion, it is anticipated that a national streamflow depletion assessment system to be develop in the future would provide customized depletion management and prevention plans based on the system assessment results regarding future data changes of the six streamflow depletion impact factors and the prospect of depletion progress.