• 제목, 요약, 키워드: Recharge volume

검색결과 18건 처리시간 0.047초

제주도 지하수위의 변화와 지하수 함양부피 (Variation of Groundwater Level and Recharge Volume in Jeju Island)

  • 박원배;김기표;이준호;문덕철;김수정;고기원;방성준;방익찬
    • Journal of Environmental Science International
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    • v.20 no.7
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    • pp.857-872
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    • 2011
  • The variation of groundwater level in Jeju Island is analyzed with the data of precipitation observed from 48 monitoring post and groundwater level observed from 84 monitoring wells during 2001 to 2009. The groundwater level rises in summer and falls in winter. The rise of groundwater level by precipitation is fast and small in the eastern region and slow and large in the western region. However, the speed of fall during the period of no rain is slower in the eastern region than in the western region. It tells that permeability is greater in the eastern region than in the western region. In this paper, we set up the base level of groundwater and calculate recharge volume between the base level and groundwater surface. During the period, the average recharge volume was $9.83{\times}10^9m^3$ and the maximum recharge volume was $2.667{\times}10^{10}m^3$ after the typhoon Nari. With these volume and the recharge masses obtained by applying the recharge ratio of 46.1%, estimated by Jeju Province (2003), the porous ratio over the whole Jeju Island is 16.8% in average and 4.6% in the case of maximum recharge volume just after typhoon Nari. A large difference in the two ratios is because that it takes time for groundwater permeated through the ground just after rain fall to fill up the empty porous part. Although the porous ratios over the whole Jeju Island obtained in this way has a large error, they give us the advantage to roughly estimate the amount of recharged groundwater mass directly from observing the groundwater level.

지하수 부존량 평가와 관리에 대한 소고 (A Note on Estimating and Managing Groundwater Reserves)

  • 이병선;박종환;명우호;손주형;이상화;심규성;송성호
    • 한국지하수토양환경학회지:지하수토양환경
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    • v.23 no.6
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    • pp.28-36
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    • 2018
  • This study was conducted to estimate groundwater reserves within a designated depth. Three methods were applied to one representative county in southern Gyeongsang province, South Korea, to estimate the groundwater reserves in the aquifers. Estimated amounts of groundwater reserves in the region ranged from $20.2{\times}10^9m^3$ to $68.7{\times}10^9m^3$ (average $37.9{\times}10^9m^3$). Groundwater recharge obtained with a recharge ratio of 16.6% was $1.1{\times}10^9m^3/year$. Exploitable groundwater with an assumption of decadal-cycle minimal rainfall of 977.0 mm/year was approximated as 72% ($0.8{\times}10^9m^3/year$) of the total replenished water by recharge. The volume of recharge and exploitable water accounted for only 1.1% and 0.8% of groundwater reserves, respectively, which indicates substantial capacity of the reservoir to supply groundwater in an event of unexpected droughts. Nonetheless, each groundwater well should strictly comply with its allocated pumping rate to avoid alluvial groundwater depletion.

인공함양시설 설치에 따른 유출특성 변화에 관한 연구 (A Study of the Variation of Runoff Characteristics Depending upon Installation of the Groundwater Recharge Facilities)

  • 최계운;김영규;정기일
    • 한국방재학회 논문집
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    • v.4 no.4
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    • pp.27-34
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    • 2004
  • 본 연구에서는 인공함양법을 적용한 유역에서의 유출특성 변화를 알아보기 위하여 실험유역을 설정하고 각각의 유역에 대하여 실제강우 실험과 강우모의 실험을 실시를 통하여 유출-침투특성을 분석하였다. 실강 우시 유출-침투특성 분석을 위해 2004년 7월 11일${\sim}$7월 17일 사이에 내린 4개의 강우사상에 대하여 분석을 실시한 결과 인공함양유역에서 유출이 발생하는 경우의 유출율 평균은 약 10.61%, 침투율 평균은 89.39%로 파악되어 유출되는 유량의 대부분이 인공함양법 적용에 의해서 침투가 가능한 것으로 나타났으며, 강우모의 실험에서는 강우강도의 변화와 상관없이 1시간의 지속시간을 가지는 60mm/hr ${\sim}$ 100mm/hr 구간에서 유출되는 유량 없이 전량이 침투되는 것으로 나타났다. 그러나, 인공함양시설을 설치한 경우라도 장기간 강우 발생시 주위의 지하수 변화에 의해서 유출이 발생할 수 있으므로 주변의 지하수위에 대한 지속적인 관찰이 요망된다.

Sustainability of freshwater lens in small islands under climate change and increasing population

  • Babu, Roshina;Park, Namsik
    • 한국수자원학회:학술대회논문집
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    • pp.145-145
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    • 2019
  • Groundwater and rainwater are the only sources of freshwater in small islands as many islands lack surface water sources. Groundwater occurring in the form of freshwater lens floating on denser seawater is highly dependent on natural recharge from rainfall. A sharp interface numerical model for regional and well scale modeling is selected to assess the sustainability of freshwater lens in the island of Tongatapu. In this study, 29 downscaled General Circulation Model(GCM) predictions are input to the recharge model based on water balance modelling. Three GCM predictions which represent wet, dry and medium conditions are selected for use in the groundwater flow model. Total freshwater volume and number of saltwater intruded wells are simulated under various climate scenarios with GCM predicted rainfall pattern, sea level rise and pumping. Simulations indicate that the sustainability of the freshwater lens is threatened by the frequent droughts which are predicted under all scenarios of recharge. The natural depletion of the lens during droughts and increase in water demands, leads to saltwater upconing under the pumping wells. Implementation of drought management measures is of utmost importance to ensure sustainability of freshwater lens in future.

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Artifical Groundwater Recharge Using Underground Piping Method

  • Ahn, Sang-Jin;Lee, Jong-Hyong
    • Korean Journal of Hydrosciences
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    • v.3
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    • pp.11-29
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    • 1992
  • Recently, rapid industrialization, urbanization and higher living standards accelerate to increase groundwater consumption resulting in continuously dropping groundwater elevations. To maintain enough groundwater volume without dropping groundwater elevations, the proper groundwater rechatge is necessary. The groundwater rechatge can be classified into two categories which are natural rechatge and artiticial rechatge. Even though the natural rechatge through by dired infiltration from the rainfall is desirable, the artificial groundwater rechatge is necessaty when the increment of groundwater consumption exceeds natural recharge rate. Well method and scattering method are utilized as artificial rechatging method, a severe disadvantage, which is the reduction of the void of soil surface, is indicated in the well method. Recently, the underground piping method, which is a scattering method, is receiving increasing attention as a proper recharging method. The method is indirectly to supply water to the underground using an underground piping system. Therefore, the void of soil surface is not severely reduced and better infiltration rate can be achieved. In this paper, the artificial groundwater rechatge using underground piping method is investigated through experiments and numerical analysis. The influence of the groundwater by underground piping method is evaluated through comparing recharging heights. Good agreements between experiments and numerical analysis are obtained and the artificial groundwater recharge by underground piping method is well tested and verified.

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불포화 토양에서 빗물의 침투특성 : 유한요소 모델과 실험결과 비교 (Rainwater Infiltration Characteristics in the Unsaturated Soil : Comparison of Finite Element Model with Experimental Results)

  • 유건선;김상래;김충일;윤현식;한무영
    • 한국지하수토양환경학회지:지하수토양환경
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    • v.16 no.6
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    • pp.27-33
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    • 2011
  • Infiltration plays an important role in the urban water cycle. Infiltration has a potential to contribute to groundwater recharge in addition to runoff reduction. However, infiltration in urban areas has been considered only as a means of runoff reduction. Conventional design methods for infiltration facilities assume soils to be fully-saturated for the sake of simplicity. The amount of groundwater recharge can not be estimated properly with this scheme. Hence, the characteristics of the unsaturated soil condition need to be considered. The finite element model using SEEP/W to estimate infiltration under the unsaturated condition is presented. Infiltration tests for Joomonjin sand are performed and the infiltration behavior of Joomoonjin sand under the unsaturated condition is measured experimentally to verify the validity of the finite element model. The results from comparing infiltrated volume between the saturated and the unsaturated conditions under the same soil and rainfall conditions show that the infiltrated volume in the unsaturated condition is two times bigger than that in the saturated condition.

Impact of predicted climate change on groundwater resources of small islands : Case study of a small Pacific Island

  • Babu, Roshina;Park, Namsik
    • 한국수자원학회:학술대회논문집
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    • pp.145-145
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    • 2018
  • Small islands rely heavily on groundwater resources in addition to rainwater as the source of freshwater since surface water bodies are often absent. The groundwater resources are vulnerable to sea level rise, coastal flooding, saltwater intrusion, irregular pattern of precipitation resulting in long droughts and flash floods. Increase in population increases the demand for the limited groundwater resources, thus aggravating the problem. In this study, the effects of climate change on Tongatapu Island, Kingdom of Tonga, a small island in Pacific Ocean, are investigated using a sharp interface transient groundwater flow model. Twenty nine downscaled General Circulation Model(GCM) predictions are input to a water balance model to estimate the groundwater recharge. The temporal variation in recharge is predicted over the period of 2010 to 2099. A set of GCM models are selected to represent the ensemble of 29 models based on cumulative recharge at the end of the century. This set of GCM model predictions are then used to simulate a total of six climate scenarios, three each (2010-2039, 2040-2069, and 2070-2099) under RCP 4.5 and RCP 8.5. The impacts of predicted climate change on groundwater resources is evaluated in terms of freshwater volume changes and saltwater ratios in pumping wells compared to present conditions. Though the cumulative recharge at the end of the century indicates a wetter climate compared to the present conditions the large variability in rainfall pattern results in frequent periods of groundwater drought leading to saltwater intrusion in pumping wells. Thus for sustaining the limited groundwater resources in small islands, implementation of timely assessment and management practices are of utmost importance.

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GIS L-THIA를 이용한 도시화에 따른 유출과 비점원오염 영향 평가 (Assessing the impact of urbanization on runoff and non-point source pollution using the GIS L-THIA)

  • 윤라영;김동희;권혁현;신승철;손광익
    • 한국수자원학회:학술대회논문집
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    • pp.1802-1806
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    • 2006
  • It is important to consider the effects of land-use changes on surface runoff, stream flow, and groundwater recharge. Expansion of urban areas significantly impacts the environment in terms of ground water recharge, water pollution, and storm water drainage. Increase of impervious area due to urbanization leads to an increase in surface runoff volume, contributes to downstream flooding and a net loss in groundwater recharge. Assessment of the hydrologic impacts or urban land-use change traditionally includes models that evaluate how land use change alters peak runoff rates, and these results are then used in the design of drainage systems. Such methods however do not address the long-term hydrologic impacts of urban land use change and often do not consider how pollutants that wash off from different land uses affect water quality. L-THIA (Long-Term Hydrologic Impact Assessment) is an analysis tool that provides site-specific estimates of changes in runoff, recharge and non point source pollution resulting from past or proposed land-use changes. It gives long-term average annual runoff for a land use configuration, based on climate data for that area. In this study, the environmental and hydrological impact from the urbanized basin had been examined with GIS L-THIA in Korea.

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사대강유역의 지하수 (Ground water in the four major basins in Korea)

  • 최승일
    • 물과 미래
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    • v.12 no.1
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    • pp.21-27
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    • 1979
  • Ground water stored in the alluvium and the rocks provides the vase flow of the streams and can be withdraw from wells and infiltration galleries. And it is also recharge naturallyby precipitation. The amount of ground water in the four major basins it is estimated to be about 137,000 million cubiv meters(Table1), while nationwide ground water storage to be about 232,000 million cubic meters. The estimation of storage volume has been made on the basis of assumed thickness of the saturated zone of the different rocks and assumed porosities of those rocks. The values of the porosity of alluvium and saprolite were assumed to be 25% and 40% respectivvely which are based on tests made of similar materials in Georgia, U.S. The volume of water in storage is believed to be a conservative estimate. Detailed geologic and hydrologic investigation should be made where and when water resources are needed.

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