J. Jpn. Soc. Soil Phy. No. +*2 p. -1./ **2 * * * Meaurement of Water evel Electrical Conductivity and Sediment Surface evel Uing Time Domain Reflectometry Hideki M IYAMOTO* Jiro C HIKUSHI* and Taek-Keun O H* * Biotron Intitute Kyuhu Univerity 0 +* + Hakozaki Higahi-ku Fukuoka 2+ 2/2+ Japan Abtract Time domain reflectometry (TDR) ha been draing a lot more attention a a ay to identify the interface in beteen di# erent dielectric media. To monitor ater level ( h ) ith electrical conductivity ( ) and iment urface level ( h ) in river by applying TDR e developed a mathematical model to evaluate thee propertie and verified it e# ectivene by meauring the dielectric contant of conductive fluid media and a oil material (and) uing TDR probe ith di# erent length. Although the determination of h in extremely high-conductive media a technically incompleted e could uccefully determine h and h ith a probe in moderateconductive media. Judging from the relatively good agreement beteen propertie evaluated from the model and oberved data e concluded the TDR meaurement could be ueful to evaluate h and h ith u$ cient accuracy for practical ue ithin an appropriate conductive range. In actual application of TDR to a river monitoring the calibration of the probe u mut be required to conduct accurate meaurement ba of the model. Key ord : Time domain reflectometry Microave Dielectric contant Water level Electrical conductivity Sediment urface level + Time Domain Re- flectometry TDR TDR TDR * 2+ 2/2+ 0 +* + :
38 +*2 **2 +331 Krohne EndreHauer Vega TDR +2. **- TDR TDR + TDR TDR Fig. + Schematic diagram of a TDR aveform Cataldo in inerting a probe partly into a dielectric et al. **0 ; Thomen et al. *** ; **- material. B eb t* t A-B t+ Thomen et al. *** ; Yu and Yu **0 ; +330 r A TDR B e t TDR /+ t t* ct e TDR 2 + c -*. +* m TDR rf A B TDR e Heimovaara et al. +33/ t RRc R TDR TDR t Rc + A B **- m TDR hb m + TDR + A e e A
: 39 n n n n A B h h e e h A A B B A a m h TDR Moret et al. **. a b h Yu and Yu **0 h m TDR Yu and Yu **0 + A B A B Sm h h b a * e e e q h h h + q q + b h b+ e h q h e baln b B b b n A Bn A b B b b b b a a TDR+** Campbell Scientific TDR a b +** *./ V +. m -** p h/ aln balnlnln * exp - b b - -+ +1/. Topp et al. +32 ; Rob- inon et al. **-b GHz Robinon et al. **-a
40 +*2 **2 * mm +*. m *+. m *.2. m *31. m *.2. m -- *.2. m *31. m */. m +*. m Fig. Schematic diagram of experimental tu #. *31. m +/ *..2 m - -/ *..2 m. mm +* mm *. +*/ *./3 mm **1. m */. m +/ DW TW TDR CaCl *.**2 *.*+0 *.*.* *.*2.. Sm. m + * ++ * ** * */ +2 *..2 m *./+ m + - - - *.*++ Sm +32+ m *. 31 m *./- m m. TDR.+ TDR+** TDR+**.++ TDR PCTDR *.2. m TDR h */. m- PCTDR DW t t t + *.** Sm t t. m mm. S m + * 31 / * ** -
: 41 - *.2. m */. m TDR Fig. - TDR aveform meaured ith a *.2. -m long probe in di# erent conductive olution. / Fig. / *.2. m *31. m h Water level ( h ) for the quare root of dielectric contant ( ) meaured ith a *.2. -m long probe and a *31. -m long probe in di# erent olution. Broken line in the figure indicate theoretical value etimated from eq. (/).. *.2. m h TDR Fig.. TDR aveform meaured ith a *.2. -m long probe in di# erent level ( h) of ditilled ater. t t.+ / *..2 m *. 31 m TDR t e h t + *.** Sm +/ 2. 3*1. *.2. m 3*1... h t t h *+. m + *32. m t t t + + h t t * + t t + +
42 +*2 **2 0 *.2. m 1 b h Fig. 1 A parameter b for electrical conductivity Fig. 0 Electrical conductivity ( e# ) meaured of fluid media ( ). ith a *.2. -m long probe for ater level ( h) in di# erent fluid media. Fitting function of eq. ( 2) for experimental data 0 1 plot are expre by broken line. b b a b e *. + *. 3-* + h. / 2 a b h + */. mm.+- *.2. m h 0 0 h.+. *.2. m -. h t b TDR b
: 43 2 h Fig. 2 Etimated electrical conductivitie of fluid media ( ) for relative ater level ( h/ ). Broken line in the figure indicate actual electrical conductivity of each fluid medium. +2 * *++ +32+ +. Sm Dalton and van Genuchten +320 TDR m b ***/. **++. ***. + + **++. Sm +*. 3 h Fig. 3 Maximum probe length ( ) being applicable to relative ater level ( h/ ) meaurement. *.**0++ 3 *.2. m a a b *.*/* *. +** *.** Sm..2-. m.2-. m *.2. m TDR +* *.2. h m t t +
44 +*2 **2 +* *.2. m ++ *.2. m *31. m h TDR Fig. +* TDR aveform meaured ith a *.2. - h m long probe in di# erent thickne of oil iment. Fig. ++ Sediment thickne ( h ) for the quare root of dielectric contant ( ) meaured ith a *.2. -m long probe and a + *+*. mm t *31. -m long probe. Solid line in the figure in the figure indicate theoretical *32. m value etimated from eq. ( +. ). t h ++ *..2 m h TDR *31. m *.2. m - - */+. m m -/ 1*/. *31. m - - */-. m m +/ 12. /. TDR e h ++ CaCl - ++ TDR TDR Cataldo A. Tarricone. Attiviimo F. and Trotta
: 45 A. (**0) : Simultaneou meaurement of dielec- Friedman S.P. (**-a) : A revie of advance in tric propertie and level of liquid uing a TDR dielectric and electrical conductivity meauremethod. J. Hydrology in pre and available at ment in oil uing time domain reflectometry. doi : +*. +*+0 /j.meaurement.**0. ++.**0. Vadoe Zone J. :....1/. +330 : TDR Robinon D.A. Schaap M. Jone S.B. Friedman S.P. +2 +0- +0.. and Gardner C.M.K. (**-b) : Conideration for Dalton F.N. and van Genuchten M.Th. ( +320) : The improving the accuracy of permittivity meauretime-domain reflectometry method for meaurcalibration ment uing time domain reflectometry : Air-ater ing oil ater content and alinity. Geoderma -2 : e# ect of cable length. Soil Sci. Soc. -1 /*. Am. J. 01 : 0 1*. Heimovaara T. J. Focke A.G. Bouten W. and Vertraten J.M. ( +33. ) : Aeing temporal variation in oil ater compoition ith time domain reflectometry. **- : in **- : ++ +/ Soil Sci. Soc. Am. J. /3 : 023032. Thomen A. Hanen B. and Schelde K. (***) : Ap- +32+ : plication of TDR to ater level meaurement. J. - pp. +00 +03 Hydrology -0 (-. ) : / /2. **- : Topp G.C. Davi J.. and Annan A.P. ( +32 ) : Elec- MS TODAY + 2 : -. tromagnetic determination of oil ater content Moret D. ópez M.V. and Arrúe J.. (**.) : TDR uing TDR : I. Application to etting front and application for automated ater level meaure- teep gradient. Soil Sci. Soc. Am. J..0 : 01 012. ment from Mariotte reervoir in tenion dic Yu X. and Yu X. (**0) : Meaurement of imulated infiltrometer. J. Hydrology 31 : 3 -/. cour by time domain reflectometry Proc. TDR **- : TDR 3- : /10/. **0. available on line at http : //engineering. purdue.edu/tdr/paper. Robinon D.A. Jone S.B. Wraith J.M. Or D. and TDR CaCl TDR : **1 + : **2 +.