## Poster Number 139

See more from this Division: S01 Soil PhysicsSee more from this Session: General Soil Physics: II (Includes Graduate Student Competition)

Monday, October 17, 2011

Henry Gonzalez Convention Center, Hall C

The objective of this study was to develop a novel methodology to use BTC of non-conservative tracers such as chloride and bromide as surrogates for the purpose of calculating pore-water velocity and corresponding pore-size spectrums in soils. Miscible displacement tests of Cl were conducted on repacked sand and undisturbed soil columns with 8.0 cm id and 13-30 cm length. The resultant BTCs were divided into about 30 segments, and amount of mobile water (

See more from this Division: S01 Soil Physics*Q*) needed to transport the amount of tracer recovered at the exit of the column for corresponding segment was calculated as_{mi}*Q*= (_{mi}*DC*x_{ri}*DP*x_{ri}*P*)x_{0}*P*, where_{r(Cr=1.0)}*DC*is the difference in dimensionless concentration,_{ri}*DP*is the difference in dimensionless pore volume,_{ri}*P*is the amount of water held in the column (simply pore volume of the column), and_{0}*P*_{r(Cr=1.0)}_{ }is dimensionless pore volume at*C*=1.0. Pore water velocity (_{r}*v*) for segment_{i}*i*was calculated as*v*= (_{i}*zl*/*t*) where,*z*is tourtuousity (-),*l*(L) is the length of the column and*t*(T) is time elapsed from traced effluent to start displacing non-traced effluent in the column. Mean radius of the pores within size class*i*was calculated, using calculated*v*with Poiseuille’s equation. Number of the pores in each size-class_{i}*i*was calculated dividing volume of effluent discharging in unit time (*Q*/(_{mi}*t*), where_{i+1}-t_{i}*t*is the time length for which_{i+1}-t_{i}*Q*is recovered) by cross-sectional area of mean pore-size calculated for size class_{mi}*i*. The predicted mean pore-water velocity (*v*) for saturated columns was calculated form geometric mean of pore-water velocity-values calculated for all the segments. Saturated mean pore-water velocity of the columns was measured, and measured (_{p}*v*) and predicted (_{m}*v*) pore-water velocity-values were converted to saturated hydraulic conductivity, multiplying_{p}*v*and_{m}*v*by saturated water content (L_{p}^{3}L^{-3}) of the columns. Correlation analysis conducted between*v*and_{m}*v*resulted in a correlation coefficient of r= 0.90._{p}See more from this Session: General Soil Physics: II (Includes Graduate Student Competition)