Impact of initial and boundary conditions on preferential flow.
Preferential flow in soil is approached by a water-content wave, WCW, that proceeds downward from the ground surface. WCWs were obtained from sprinkler experiments with infiltration rates varying from 5 to 40 mm h(-1). TDR-probes and tensiometers measured volumetric water contents theta(z,t) at seven depths, and capillary heads, h(z,t) at six depths in a column of an undisturbed soil. The wave is characterized by the velocity of the wetting front, c(W), the amplitude, w(S), and the final water content, theta*. We tested with uni-variate and bi-variate linear regressions the impacts of initial volumetric water contents, theta(ini), and input rates, q(S), on c(W), w(S) and theta*. The test showed that theta(ini) influenced theta* and w(S) and q(S) effected c(W). The expected proportionality of w(S) approximately = qs(1/3) was weak and c(W) approximately = qs(2/3) was strong.
Hincapié
Ingrid
I
Soil Science Section, Department of Geography, University of Bern, Hallerstrasse 12, CH-3012 Bern, Switzerland. hincapie@giub.unibe.ch
Germann
Peter F
PF
D016014:Linear Models; D012987:Soil; D014872:Water Movements
D012987:Soil