• Title/Summary/Keyword: Recharge Rate

Search Result 126, Processing Time 0.031 seconds

Estimation of Groundwater Recharge by the Water Balance Analysis using DAWAST Model (일 유출모형의 물수지 분석에 의한 지하수 함양량 추정)

  • Lee, Duk-Joo;Lee, Ho-Chun;Lee, Soon-Kwang;Kim, Tai-Cheol
    • Proceedings of the Korean Society of Agricultural Engineers Conference
    • /
    • 2003.10a
    • /
    • pp.431-434
    • /
    • 2003
  • This research developed a method for the estimation of groundwater recharge by yielding daily soil moisture content and watershed evapotranspiration from the water balance concept of the unsaturated and saturated layers in rainfall-runoff model called DAWAST. The goal of the research is to estimate the groundwater recharge fulfilling conditions of the safe discharge for any season. To meet this goal, the data of groundwater level and stream flow rate have been monitored in a study area and used to validate the model.

  • PDF

A Study on Efficient Improvement Method of Rainwater Utilization Facilities in Jeju Island (제주지역 빗물이용시설의 효율적 개선방안 연구)

  • Park, Won-Bae;Moon, Deok-Cheol;Koh, Gi Won
    • Journal of Soil and Groundwater Environment
    • /
    • v.17 no.6
    • /
    • pp.1-8
    • /
    • 2012
  • This study is to suggest a few efficient ways of rainwater utilization, through monitoring and analyzing 143 rainwater storage systems and 110 artificial recharge systems, which are installed in the recommended facilities by law, among the rainwater harvesting systems in Jeju Island. In the case that catchment facilities are damaged, rainwater could be contaminated by leaves and debris so that the rates of rainwater usages come to be lower. It is possible that contaminated rainwater could contaminate artificial recharge wells or rainwater discharging out of the rainwater harvesting system could result in flood and damage for the downgradient area. For maintaining high quality of rainwater and increasing rainwater utilization rate, it is necessary to install screening facilities and purification plant functioning precipitation and filtration. Also, in order to efficiently preclude the overflowing rainwater exceeding storage capacity, it is recommended to associate rainwater storage tanks with artificial recharge well or infiltration trench facilities.

Monitoring of Seawater Intrusion in Unconfined Physical Aquifer Model using Time Domain Reflectometry (자유면 대수층 모형에서의 TIME DOMAIN REFLECTOMETRY를 이용한 해수침투 모니터링)

  • 김동주;하헌철;온한상
    • The Journal of Engineering Geology
    • /
    • v.13 no.1
    • /
    • pp.17-27
    • /
    • 2003
  • In this study, a phenomenon of saltwater intrusion was monitored under various conditions regarding recharge and pumping rate using time domain reflectometry for a laboratory scale unconfined aquifer to verify the basic theory behind seawater intrusion and to investigate movement of salt-freshwater interface in accordance with the ratio of pumping and recharge rate. Results showed that a thick mixing zone was formed at the boundary instead of a sharp salt-freshwater interface that was assumed by Ghyben and Herzberg who derived an equation relating the water table depth $(H_f)$ to the depth to the interface $(H_s)$. Therefore our experimental results did not agree with the calculated values obtained from the Ghyben and Herzberg equation. Position of interface which was adopted as 0.5 g/L isochlor moved rapidly as the Pumping rate $(Q_p)$ increased for a given recharge rate $(Q_r)$. In addition, interface movement was found to be about 7 times the ratio of $Q_p/Q_r$ in our experimental condition. This indicates that Pumping rate becomes an important factor controlling the seawater intrusion in coastal aquifer.

Sensitivity Analysis of Artificial Recharge in Consideration of Hydrogeologic Characteristics of Facility Agricultural Complex in Korea : Hydraulic Conductivity and Separation Distance from Injection Well to Pumping Well (국내 시설농업단지의 수리지질 특성을 고려한 인공함양 민감도 분석 : 수리전도도 및 주입정과 양수정의 이격거리)

  • Choi, Jung Chan;Kang, Dong-hwan
    • Journal of Environmental Science International
    • /
    • v.28 no.9
    • /
    • pp.737-749
    • /
    • 2019
  • In this study, the sensitivity analysis of hydraulic conductivity and separation distance (distance between injection well and pumping well) was analyzed by establishing a conceptual model considering the hydrogeologic characteristics of facility agricultural complex in Korea. In the conceptual model, natural characteristics (topography and geology, precipitation, hydraulic conductivity, etc.) and artificial characteristics (separation distance from injection well to pumping well, injection rate and pumping rate, etc.) is entered, and sensitivity analysis was performed 12 scenarios using a combination of hydraulic conductivity ($10^{-1}cm/sec$, $10^{-2}cm/sec$, $10^{-3}cm/sec$, $10^{-4}cm/sec$) and separation distance (10 m, 50 m, 100 m). Groundwater drawdown at the monitoring well was increased as the hydraulic conductivity decreased and the separation distance increased. From the regression analysis of groundwater drawdown as a hydraulic conductivity at the same separation distance, it was found that the groundwater level fluctuation of artificial recharge aquifer was dominantly influenced by hydraulic conductivity. In the condition that the hydraulic conductivity of artificial recharge aquifer was $10^{-2}cm/sec$ or more, the radius of influence of groundwater level was within 20 m, but In the condition that the hydraulic conductivity is $10^{-3}cm/sec$ or less, it is confirmed that the radius of influence of groundwater increases sharply as the separation distance increases.

Assessment on Saline Water Intrusion between Types of Injections of Artificial Reclaimed Water and Extractions in Artificial Aquifer (인공 하수처리수 주입과 양수 방식에 따른 인공 대수층의 해수침투평가)

  • Kang, Jeong-Ok;Lee, So-Jung;Kim, Chang-Gyun
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.28 no.6
    • /
    • pp.603-612
    • /
    • 2006
  • The study with laboratory sandbox model has been carried out to address potential use of reclaimed water, as a way for artificially recharging the coastal aquifer, to effectively prevent from seawater intrusion. To do this, we assessed hydraulic and geochemical properties depending upon various extraction and recharging conditions. While solely being recharged, the intrusion could be significantly retarded than those of recharge and extraction implied together. At 0.5 to 2 for the ratio of the extraction over the recharge rate, the fresh water was exploited from the tank, where the void regime was simultaneously saturated with the recharged water. In the meantime, the saline water zone was diluted and back-tracked by the recharged water due to forming a hydraulic geochemical barrier around the injection well. However, if the ratio was being increased to greater than 4, saltwater more deeply intruded to the freshwater zone because the artificial recharge was not sufficiently supplied to timely back-fill the void space. When the aquifer water was intermittently extracted at the ratio of $0.5{\sim}2$ over the recharge rate, the value of S.M.I. decreased, but increasing it to more than 4 unlikely escalated the value of S.M.I as much as $3{\sim}47%$ indicating that the salt water intruded. It finally revealed that the proper ratio of extraction/recharge or intermittent extraction would efficiently retracted seawater intrusion while the freshwater sources could be conservatively utilized.

Coupled Model Development between Groundwater Recharge Quantity and Climate Change Using GIS (GIS를 이용한 기후변화 연동 지하수 함양량 산정 모델 개발 및 검증)

  • Lee, Moung-Jin;Lee, Joung-Ho
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.14 no.3
    • /
    • pp.36-51
    • /
    • 2011
  • Global climate change is disturbing the water circulation balance by changing rates of precipitation, recharge and discharge, and evapotranspiration. Groundwater, which occupies a considerable portion of the world's water resources, is related to climate change via surface water such as rivers, lakes, and marshes. In this study, the authors selected a relevant climate change scenario, A1B from the Special Report on Emission Scenario (SRES) which is distributed at Korea Meteorological Administration. By using data on temperature, rainfall, soil, and land use, the groundwater recharge rate for the research area was estimated by periodically and embodied as geographic information system (GIS). In order to calculate the groundwater recharge quantity, Visual HELP3 was used as main model, and the physical properties of weather, temperature, and soil layers were used as main input data. General changes to water circulation due to climate change have already been predicted. In order to systematically solve problems of ground circulation system, it may be urgent to recalculate the groundwater recharge quantity and consequent change under future climate change. The space-time calculation of changes of the groundwater recharge quantity in the study area may serve as a foundation to present additional measures to improve domestic groundwater resource management.

Groundwater Recharge and Discharge in the Urban-rural Composite Area (도농복합지역 지하수 함양과 배출에 대한 연구)

  • Lee, Byung-Sun;Hong, Sung-Woo;Kang, Hee-Jun;Lee, Ji-Seong;Yun, Seong-Taek;Nam, Kyoung-Phile
    • Journal of Soil and Groundwater Environment
    • /
    • v.17 no.2
    • /
    • pp.37-46
    • /
    • 2012
  • This study was conducted to identify groundwater recharge and discharge amounts of a representative urban-rural composite area located in Yongin city, Kyounggi-do, Korea. Groundwater recharge would be affected by mainly two processes in the study area: rainfall and leakage from public water pipelines including water-supply and sewage system. Groundwater recharge rate was estimated to be 13.5% by applying annual groundwater level data from two National Groundwater Monitoring Stations to the master regression curve method. Subsequently, the recharge amounts were determined to be $13,253{\times}10^3m^3/yr$. Leakage amounts from water-supply and sewage system were estimated to be $3,218{\times}10^3$ and $5,696{\times}10^3m^3/yr$, respectively. On the whole, a total of the recharge amounts was $22,167{\times}10^3m^3/yr$, of which 60% covers rainfall recharge and 40% pipeline leakage. Groundwater discharge occurred through three processes in the composite area: baseflow, well pumping, and discharge from urban infrastructure including groundwater infiltration into sewage pipeline and artificial extraction of groundwater to protect underground facilities from submergence. Discharge amounts by baseflow flowing to the Kiheung agricultural reservoir and well pumping were estimated to be $382{\times}10^3$ and $1,323{\times}10^3m^3/yr$, respectively. Occurrence of groundwater infiltration into sewage pipeline was rarely identified. Groundwater extraction amounts from the Bundang subway line as an underground facility were identified as $714{\times}10^3m^3/yr$. Overall, a total of the discharge amounts was determined to be $2,419{\times}10^3m^3/yr$, which was contributed by 29% of artificial discharge. Even though groundwater budget of the composite area was identified to be a surplus, it should be managed for a sound groundwater environment by changing deteriorated pipelines and controlling artificial discharge amounts.

Estimation of Exploitable Groundwater in the Jinju Region by Using a Distributed Hydrologic Model (분포형 수문모형을 이용한 진주지역의 지하수 개발가능량 추정)

  • Lee, Jeong Eun;Chung, Il-Moon;Lee, Jeongwoo;Kim, Min Gyu
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.41 no.6
    • /
    • pp.655-662
    • /
    • 2021
  • This study aimed to estimate exploitable groundwater for the sustainable supply of groundwater in the Jinju region of South Gyeongsang Province. As an integrated hydrologic analysis model, SWAT-MODFLOW was used to estimate the distributed groundwater recharge in consideration of land use and soil distribution. As a result of calibration of the model, the coefficient of determination between the observed flow and the simulated flow was 0.75-0.80, which was good. The simulated groundwater recharge rate showed a spatio-temporal distribution due to heterogeneous watershed characteristics. The amount of groundwater recharge shows lower values over winter and spring, but it increases according to the pattern of precipitation in summer and autumn. The calculated average annual groundwater recharge was compared with the result using the baseflow separation method of natural flow, and the deviation of both results was small, within 3 %, confirming the validity of the estimated groundwater recharge. Exploitable groundwater is defined as the amount of recharge corresponding to low flow with 10 years of return period. Therefore, in this study, 14.2 % of the annual precipitation was found to be exploitable as a result of calculating the amount of recharge at a 10-year frequency using a statistical frequency analysis technique.

Groundwater Flow and Water Budget Analyses using HydroGeoSphere Model at the Facility Agricultural Complex (시설농업단지에서 HydroGeoSphere 모델을 이용한 지하수 유동 및 물수지 분석)

  • Kang, Dong-hwan;So, Yoon Hwan;Kim, Il Kyu;Oh, Se-bong;Kim, Suhong;Kim, Byung-Woo
    • The Journal of Engineering Geology
    • /
    • v.27 no.3
    • /
    • pp.313-322
    • /
    • 2017
  • The purpose of this study is to estimate the surface and subsurface flows through the modelling of the model area and facility agricultural complex, and to calculate the groundwater recharge rate through water budget analysis. From results of surface flow modeling, the surface water is flowed to a depth of about 1 to 5 meters from the upper region (northeast) to the lower region (southeast) of the Miryang River. At the M01 point (upper), the observed surface water flux and the model surface water flux are consistent. At the M02 points (lower), the observed surface water flux and the model surface water flux are a difference of 1%. From results of subsurface flow modeling, the depth of groundwater is similar to elevation in the river and higher to the forest area. Ground water depth considering groundwater pumping is that the model values appears higher than the observed values to be within 1.5 m. From results of surface-subsurface integrated modeling, the groundwater recharge area is estimated about 90% of the model area, and the groundwater recharge rate is estimated $1.92{\times}10^5m^3/day$. From results of annual water budget analysis, the groundwater recharge rate per unit area is estimated to be 503.9 mm/year, and average annual rainfall is estimated at around 39%.

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

  • Lee, Byung Sun;Park, Jong Hwan;Myoung, Wooho;Son, Joohyeong;Lee, Sanghaw;Shim, Gyuseong;Song, Sung-Ho
    • Journal of Soil and Groundwater Environment
    • /
    • v.23 no.6
    • /
    • pp.28-36
    • /
    • 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.