TY  - JOUR
AU  - Vanderborght, J.
AU  - Vereecken, H.
TI  - Estimation of local scale dispersion from local breakthrough curves during a tracer test in a heterogeneous aquifer : the Lagrangian approach
JO  - Journal of contaminant hydrology
VL  - 54
SN  - 0169-7722
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - PreJuSER-437
SP  - 141 - 171
PY  - 2002
N1  - Record converted from VDB: 12.11.2012
AB  - The local scale dispersion tensor, D-d, is a controlling parameter for the dilution of concentrations in a solute: plume that is displaced by groundwater flow in a heterogeneous aquifer. In this paper, we estimate the local scale dispersion froth time series or breakthrough curves, BTCs, of Br- concentrations that were measured at several pints in a fluvial aquifer during a natural gradient tracer test at Krauthausen. Locally Measured BTCs were characterized by equivalent convection dispersion parameters: equivalent velocity, nu(eq)(x) and expected equivalent dispersivity, <lambda(eq)(x)>. A Lagrangian framework was used to approximately predict these equivalent parameters in terns of the spatial covariance of log(e) transformed conductivity and the local scale dispersion coefficient.The approximate Lagrangian theory illustrates that <lambda(eq)(x)> increases with increasing travel distance and is much larger than the local scale dispersivity, lambda(d). A sensitivity analysis indicates that <lambda(eq)(x)> is predominantly determined by the transverse component of the local scale dispersion and by the correlation scale of the hydraulic conductivity in the transverse to flow direction whereas it is relatively insensitive to the longitudinal component of the local scale dispersion. By comparing predicted <lambda(eq)(x)> for a range of D-d values with <lambda(eq)(x)> obtained from locally measured BTCs, the transverse component of D-d, D-dT, was estimated. The estimated transverse local scale dispersivity, lambda(dT) = D-dT/U-1 (U-1 = mean advection velocity) is in the order of 10(1)-10(2) mm, which is relatively large but realistic for the fluvial gravel sediments at Krauthausen. (C) 2002 Elsevier Science B.V. All rights reserved.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000173429700008
DO  - DOI:10.1016/S0169-7722(01)00143-7
UR  - https://juser.fz-juelich.de/record/437
ER  -