A study on the Measurement of Soil Water Concentration by Time Domain Reflectometry

TDR(Time Domain Reflectometry)을 이용한 토양수농도 측정에 관한 연구

  • Park, Jae-Hyeon (Research Institute of Engineering Science, Seoul National University)
  • 박재현 (서울대학교 공학연구소 특별연구원)
  • Published : 1998.04.01

Abstract

Monitoring solute transport has been known to be difficult especially for the unsaturated soil. The object of this study is to investigate the TDR application to monitoring solute concentration in the vadose zone. The TDR calibration test was conducted for soil samples with various water contents and concentrations. The voltage attenuation of electromagnetic wave of TDR was used to estimate the bulk electrical conductivity of a soil. The relationship between the bulk soil electrical conductivity and the solute concentration was assumed to be linear at a constant volumetric soil water content. In this study four proposed relationships were compared using data obtained from KCI solution at three different concentrations. Relationships given by Topp, Daltaon, Yanuka showed the linearity between the bulk soil electrical conductivity and the solute concentration, which were more pronounced than Zegelin's. The three relationships were found to be useful to measure the solute concentration in the vadose zone. In addition, TDR method was proven to be a viable technique in monitoring solute transport through unsaturated soils in transient flow condition.

비포화대에서의 지하수 오염원의 이송을 관측하는 것은 매우 어려운 거승로 알려져 있다. 본 연구에서는 함수량과 농도가 다른 시료를 이용하여 비포화 용존 오염원의 농도를 측정하기 위한 TDR의 적용가능성에 대한 검정실험을 수행하였다. 초기전자기파에 대한 TDR반향파의 감쇄정도를 이용하여 토양의 총전기전도도를 측정하게 되는데 이때 함수량이 일정할 경우 총전기전도도와 토양수의 농도관계는 선형관계를 유지한다는 가정을 기본으로한다. 본 연구에서는 세가지의 농도와 체적함수량을 갖는 시료를 성형하고 이때의 TDR 반향곡선을 측정하여 Dalton 등(1984), Topp 등(1988), Yanuka 등(1988), Zegelin 등 (1989)이 제안한 추정식으로 통초양전기전도도를 구하였다. 실험결과 Zegelin등이 제안한 식을 제외한 세 가지 식들은 매우 좋은 토양수의 농도와 총전기전도도의 선형관계를 나타내었다. 따라서 이 세가지 추정식들은 용존 오염원의 농도를 추정함에 있어 매우 유용한 식으로 판단되며 이 추정식들을 이용하는 TDR 비포화 용존 오염원 측정법은 실내실험과 현장실험에 있어 매우 유용하리라 판단된다.

Keywords

References

  1. 한국수자원학회지 v.30 no.6 TDR을 이용한 토양함수량의 측정 박재현;윤성용;김상준;선우중호
  2. '97년도 한국수자원학회 학술발표회 논문집 Volumetric Pressure Plate Extractor를 이용한 물보유함수 측정 윤성용;박재현;김상준;선우중호
  3. Water Resour. Res. v.25 Field sacle transport of bromide in an unsaturared soil, 1, Experimental methodology and results Butters, G.L.;Jury, W.A.;Ernst, F.F.
  4. Science v.224 Time domain reflectometry : Simultaneous measurement of soil water content and electrical conductivity with a single probe Dalton, F.N.;Herkelrath, W.N.;Rawlins, D.S.;Rhoades, J.D.
  5. Water Resour. Res. v.27 Three-dimensional field study of solute transport through unsaturated layered porous media, 1, Methodology, mass recovery, and mean transport Ellswoth, T.R.;Jury, W.A.;Ernst, S.S.;Shoues, P.J.
  6. Algorihma for determination of travel times from TDR wave from USDA-ARS Evett, S.R.
  7. Water Resour. Res. v.18 A field test of the transfer function model for predction solute transport Jury, W.A.;Stolzy, L.H.;Shouse, P.
  8. Soil Sci. Soc. Am. J. v.56 Field measurement of solute travel times ustinf Time Domain Reflectometry Kachanoski, R.G.;Pringle, E.;Ward, A.
  9. Econ Environ Geol. v.29 no.6 Application of an autmated time domain reflectometry to solute transport study at field scale : Experimental mehtodology and calibration of TDR Kim, D.J.
  10. Econ. Environ. Geol. v.29 no.6 Application of an automated time domain reflectometry to solute transport study at field scale : Transport concept Kim, D.J.
  11. Electromagnetics(4th ed.) Kraus, J.D.
  12. Soil Sci. Soc. Am. J. v.55 Time domain reflectometry measurments of water content and electrical conductivity of layered soil column Nadler, A.;Dasberg, S.;Lapid, I.
  13. Soil salinity under irrigation Principles and methods of monitoring soil salinity Rhoades, J.D.;Shainberg, I.(ed.)
  14. Soil Sci. Soc. Am. J. v.53 Soil electrical conductivity and soil salinity : New formulations and calibrations Rhoades, J.D.;Manteghi, N.A.;Shouse, P.J.;Alves, W.J.
  15. Soil Sci. Soc. Am. J. v.51 Solute transport through a stony soil Schulin, R.;Wierenga, P.J.;Fluhler, H.;Leuenberger, J.
  16. Soil Sci. Soc. Am. J. v.51 Solute transport in undisturbed columns of an aggregated tropical soil : Preferential flow effects Seyfried, M.S.;Rao, P.S.C.
  17. Water Resour. Res. v.16 Electromagnetic determination of soil water content : Measurement in coaxial transmission lines Topp, G.C.;Davis, J.L.;Annan, A.P.
  18. Advances in irrigation v.3 Time domain reflectometry(TDR) and its application to irrigation scheduling Topp, G.C.;Davis, J.L.;Daniel Hillel(ed.)
  19. Water Resour. Res. v.24 Determination of electrical conductivity using Time Domain Reflectometry : Soil and water experiments in coaxial lines Topp, G.C.;Yanuka, M.;Zebchuk, W.D.;Zegelin, S.
  20. Soil Sci. Soc. Am. J. v.45 Chloride movement in undisturbed soil colunn Tyler, D.D.;Thomas, G.W.
  21. Soil Sci. Soc. Am. J. v.41 Model calculation for the extraction of soil water by ceramic cups and plates Tyler, D.D.;Thomas, G.W.
  22. Soil Sci. Soc. Am. J. v.41 Mass transfer studies in sorbing porus media. II. Experimental evaluation with tritium van Genuchten, M.Th;Wierenga, P.J.
  23. Can. J. Soil. Sci. v.70 A new method to measure bulk electrical conductivity in soils with Time Domain Reflectometry van Loom, W.K.P.;Perfect, E.;Groenevelt, P.H.;Kay, B.D.
  24. Soil Sci. Soc. Am. J. v.58 Laboratory measurements of solute transport using Time Domain Reflectomery Ward, A.L.;Kachanoski, R.G.;Elrick, D.E.
  25. Water Resour. Res. v.24 Multiple reflection and attenuation of Time Domain Reflectomery pulses : Theoretical considerations for application to soil and water Yanuka, M.;Topp, G.C.;Zegelin, S.;Zebchuk, W.D.
  26. Water Resour. Res. v.25 Improved field prodes for soil water content and electrical conductivity measurement ustinf Time Domain Refluctomerty Zegelin, S.J.;White, I.;Jenkins, D.R.