• Title/Summary/Keyword: collector well

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Groundwater Productivity and Rehabilitation of Radial Collector Wells for Agriculture near Okseong Underground Dam

  • Jeon, Hang-Tak;Hamm, Se-Yeong;Hong, Soun-Ouk;Lee, Sang Yong;Kim, Hyoung-Soo
    • Journal of the Korean earth science society
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    • v.41 no.4
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    • pp.381-390
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    • 2020
  • When a radial collector well is installed and operated for agricultural purposes, negative impacts may be observed over time due to the clogging of horizontal arms, such as reduced groundwater discharge and water quality deterioration. When radial collector well No. 2 was rehabilitated using the high-pressure impulse generation technique, the specific capacity and transmissivity were increased by 43.1 and 100.6%, respectively. In contrast, according to air surging, the specific capacity and transmissivity increased by 33.8 and 85.8%, respectively, compared to the initial rate before rehabilitation. During the operation of radial collector wells since construction, the time of well rehabilitation can be effectively determined by continuously monitoring the groundwater level and pumping rate of the radial collector wells, thereby preventing a decrease in productivity.

Evaluation of Well Production by a Riverbank Filtration Facility with Radial Collector Well System in Jeungsan-ri, Changnyeong-gun, Korea (경남 창녕군 증산리 일대 방사집수정을 활용한 강변 여과수 개발량 평가)

  • Lee, Eun-Hee;Hyun, Yun-Jung;Lee, Kang-Kun;Kim, Hyoung-Soo;Jeong, Jae-Hoon
    • Journal of Soil and Groundwater Environment
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    • v.15 no.4
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    • pp.1-12
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    • 2010
  • Well production by a riverbank filtration facility with multi-radial collector well systems in Jeungsan-ri, Changnyeong gun, Korea was evaluated. In this study, the drawdown at collector wells due to pumping and groundwater inflow rates along the horizontal arms of the collector wells were computed through numerical simulations. Sensitivities of the well production to hydraulic conductivity and well flow coefficient, which represents the resistance to the flow from the aquifer to the horizontal arms, were analyzed. Simulation results showed that, with given proposed pumping rate conditions, the drawdown in the caisson exceeded maximum drawdown constraints in the study site and the adjustment of the pumping rate at each well is needed. The drawdown is affected by the hydraulic conductivity of the main aquifer and the well flow coefficient, which means the profound field investigation of the study site is needed to accurately estimate the efficiency of riverbank filtration through radial collector wells.

Analysis on the Effect of Infiltration Collector Well Installation on the Water Control (침투통의 설치에 따른 치수효과 분석)

  • Shim, Jae-hyun;Lee, Cheol-kyu;Lee, Jong-kook;Kim, Jin-young
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.298-302
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    • 2004
  • In this study, the runoff reduction effect was analyzed quantitatively focusing on the infiltration collector well located in the test area. On the basis of the analysis of the data obtained by examining the real-time measurement field data, the runoff reduction was examined through the measured rainfall of the year 2003 by applying the analysis result, with the PCSWMM model to the Kiheung-Gugal residential area, which is selected as the test basin. According to the analysis, it is revealed that an infiltration collector well can reduce up to $65\~98\%$ of runoffs, compared to a conventional one. For measured rainfalls, an infiltration collector well was able to reduce up to $15\~23\%$ of runoffs and $3\~25\%$ of peak runoffs. These results show that the effects of infiltration collector wells might vary with rainfall intensity and its duration. However, the infiltration collector well was confirmed as the one of the alternatives of runoff reduction facilities in urbanized catchment.

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field Study on Effects of Runoff Reduction in the Infiltration Collector Well (현장자료를 이용한 침투집수정의 유출저감 효과에 관한 연구)

  • Jang, Bok-Jin;Yeo, Woon-Kwang
    • Journal of Korea Water Resources Association
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    • v.35 no.5
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    • pp.611-618
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    • 2002
  • In order to investigate the performance of the infiltration collector well and its effect on the runoff reduction, real-time field measurements are carried out. Based on these field data measured at Seongnam, Osan and Cheongju sites, the runoff reduction volumes and the peaks-cut-rate are quantitatively analyzed and compared with the total rainfall amount, the 10min averaged and the 10min maximum rainfall intensity. This results show that the infiltration collector well is very effective to reduce the runoff in urban area, which gives environmentally the positive to supply ground waters. It is also presented that the infiltration collector well is able to reduce up to 70% of the runoff and 40~70% of peaks, compared to a general one.

A Proposal for the Number of Investigation Wells for Optimal Radial Collector Well Design (방사형 집수정의 적정 설계를 위한 조사 물량 제안)

  • Choi, Myoung-Rak;Kim, Gyoo-Bum
    • Journal of Soil and Groundwater Environment
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    • v.25 no.2
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    • pp.1-8
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    • 2020
  • In general, the estimation of optimum yield for the radial collector well is determined by the empirical equation or numerical modeling, in which hydraulic conductivity of the aquifer is a main influence factor. Hydraulic conductivities of 164 soil samples collected from boreholes and horizontal wells (average length: about 50 m) installed during well construction in the Anseong stream were drawn in two-dimensional map by the Kriging method and utilized in this study. Hydraulic conductivity analyses by Representative Elementary Count (REC) indicated the average hydraulic conductivity is similar to that of the pumping test when the number of samples reaches about 1,000, which correspond to 1,000 ㎡. Pumping test was also conducted at 1 pumping well and 13 observation wells to estimate hydraulic conductivities at each observation well. REC analysis indicated that the average value of hydraulic conductivity calculated from at least four observation wells is valid as a representative value. The overall result suggested that multiple observation wells or multiple pumping-observation well systems that are located within the range of horizontal wells should be utilized to properly estimate the representative hydraulic conductivity values and the yield of a radial collector well.

Analysis of Long-term Thermal Performance of Solar Thermal System Connected to District Heating System (지역난방 적용 태양열시스템의 장기 열성능 분석)

  • Baek, Nam-Choon;Shin, U-Cheul
    • Journal of the Korean Solar Energy Society
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    • v.27 no.4
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    • pp.167-173
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    • 2007
  • This study analyzed by simulation using TRNSYS as well as by experiment on the solar district heating system installed for the first time for the district heating system in Bundang. Simulation analysis using TRNSYS focused on the thermal behavior and long-term thermal efficiency of solar system. Experiment carried out for the reliability of simulation system. This solar system where the circuits of two different collectors, flat plate and vacuum tube collector, are connected in series by a collector heat exchanger, and the collection characteristics of each circuit varies. Therefore, these differences must be considered for the system's control. This system uses variable flow rate control in order to obtain always setting temperature of hot water by solar system. Specifically, this is a system that heats returning district heating water (DHW) at approximately $60^{\circ}C$ using a solar collector without a storage tank, up to the setting temperature of approximately $85{\sim}95^{\circ}C$ To realize this, a flat plate collector and a vacuum tube collector are used as separate collector loops. The first heating is performed by a flat plate collector loop and the second by a vacuum tube collector loop. In a gross collector area basis, the mean system efficiency, for 4 years, of a flat plate collector is 33.4% and a vacuum tube collector is 41.2%. The yearly total collection energy is 2,342GJ and really collection energy per unit area ($m^2$) is 1.92GJ and 2.37GJ respectively for the flat plate vacuum tube collector. This result is very important on the share of each collector area in this type of solar district heating system.

Numerical Analysis of Horizontal Collector Well in Riverbank Filtration (수평 방사형 집수정 활용 강변여과 취수 수치 분석)

  • Kim, Hyoung-Soo;Jeong, Jae-Hoon
    • Journal of Soil and Groundwater Environment
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    • v.14 no.1
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    • pp.1-10
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    • 2009
  • Groundwater flow due to intake of horizontal collector well in riverbank filtration site was analyzed by use of numerical groundwater modeling program (FEFLOW 5.1). Drawdowns of groundwater table nearby collector well were evaluated according to variations of several conditions; pumping rate, thickness of aquifer, offset distance from well to shore line of stream, conductance of streambed. It is observed that the drawdowns of groundwater table are clearly changed according to the variations of these conditions. The results of sensitive analysis shows that the thickness of alluvial aquifer and the offset distance are more sensitive than the conductance of streambed in evaluation of drawdown. This result implies that hydrogeological conditions, as like thickness of aquifer and its distribution in the site are important factors in site selection and evaluating the availability of riverbank filtration intake using horizontal collector well system. It is also revealed that numerical modeling using FEFLOW with 1-D discrete element feature can give efficient quantitative evaluation of horizontal collector well and estimation of availability of riverbank filtration site.

An Experimental Study on the Distributions of Residual Head and Discharge Rate along Collector Well Laterals of a Model Riverbed Filtration (하상여과의 집수관 모형에서 잔류수두와 유입율 분포에 관한 실험연구)

  • Ahn, Kyu-Hong;Moon, Hyung-Joon;Kim, Kyung-Soo;Kim, Seung-Hyun
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.12
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    • pp.1305-1310
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    • 2005
  • As a way to the optimum design of the collector well lateral in riverbed filtration, experiments were performed using sand tanks which were connected to form a model lateral system. Measured were the residual hydraulic heads along the laterals, the discharge rates at each sand tank and the production rates at the collector well while the model laterals were operated with various scenarios of changing parameters including water level of the collector well, the lateral diameter and length, and the hydraulic conductivity of the sand. Results showed that riverbed filtration could be more efficient when the resistance in the lateral was weak compared with the resistance in the sand, which was indicated by the more flattened distribution of the residual hydraulic heads along the lateral. Results also showed that the discharge rate increased exponentially with the approach to the collector well, and that the exponent increased as the lateral diameter decreased and/or the hydraulic conductivity of the sand increased. It was also seen that the well production increased with the increase in the lateral length and diameter although the marginal productivity decreased. It could be concluded that the axial flow velocity in the lateral was an important factor governing the efficiency of a lateral in riverbed filtration and that the maximum entrance velocity to the collector well, over which the efficiency decreased drastically, was about 1 m/sec under the conditions of this study.

Evaluation of pumping capacity of radial collector wells using Milojevic's equation in the National River Watershed, Korea (Milojevic 경험식을 활용한 주요 국가하천 유역에서 방사형집수정의 강변여과수 취수가능량 평가)

  • Oh, Se-Hyoung;Jeong, Jae-Hoon;Park, Sang-Gyu
    • Journal of Soil and Groundwater Environment
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    • v.17 no.3
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    • pp.10-20
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    • 2012
  • The pumping capacity of riverbank filtration using radial collector wells at the Geum, Yeongsan, Seomjin, and Nakdong rivers was evaluated using Milojevic's equation. Assessment of the radial collector wells' pumping capacity in riverbank filtration was carried out using a case study in which one set of collector wells is installed in the watershed of each river. Nakdong River was evaluated to have the highest pumping capacity for riverbank filtration. The areas capable of producing over 10,000 $m^3$ per day were found mostly in the Nakdong River.

Relationship between Groundwater Level Changes and Aquifer Characteristics during Pumping at a Radial Collector Well (방사형 집수정 취수시 대수층 특성에 따른 지하수위의 변화)

  • Choi, Myoung-Rak;Lee, Ho-Jeong;Kim, Gyoo-Bum
    • The Journal of Engineering Geology
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    • v.29 no.3
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    • pp.279-288
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    • 2019
  • The groundwater drawdown at each monitoring well near a radial collector well along Anseong Stream, Korea, was measured and compared with the calculated drawdown using the mirror well concept. The drawdown calculation is performed by treating the collector well as a large vertical well in a homogeneous isotropic aquifer. The measured drawdown at each monitoring well is slightly different from the calculated value due to anisotropy in the hydraulic conductivity and aquifer thickness. The difference between the measured and calculated values at Well OW-7 is large, reaching approximately 48 cm, because a horizontal well is not installed along this direction. Sensitivity analysis of the hydraulic conductivity and aquifer thickness indicates that the hydraulic conductivity is more sensitive to groundwater level changes. Groundwater level changes become a concern when a radial collector well with a large pumping rate capacity is installed, which highlights the need to thoroughly investigate the aquifer characteristics in the surrounding area.