الفهرس 
Experimental Testing of the Relationship between Hydraulic Conductivity, Sorptivity, and One-Dimensional and ThreeDimensional Infiltration RatOnly 14 pages are availabe for public view
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Abstract
Infiltration rate (IR), saturated hydraulic conductivity (Ks), IRbasic-Ks ratio (parameter u), and sorptivity (S) were determined in clay and sand at two initial moisture contents (air-dry, L1,
and a moisture content (L2) approximately midway between air-dry and field capacity), experiments were performed on five soil configurations, four columns of 1.85, 4.0, 8.4, and
10.15 cm in diameter (confined infiltration) and a pot 41 cm in diameter (unconfined
infiltration).
Data revealed that the final (basic) IR (IRbasic) was greater for L1. IRbasic values of clay showed decreasing trend as the column diameter increases from 1.85 to 8.4 cm. However, the
10.15 cm values were greater than those of the two intermediate column sizes. The apparent effect of column size on measured IR makes it important to take determined values with care.
It also suggests that determining IR might be better if measured in very wide columns or under unconfined (3-D) rather than confined conditions whenever possible. IR values are consistently and for all column diameters greater for soils with lower initial moisture content
(L1). This is caused by the greater water potential difference and gradient in drier soil.
For all column diameters except the 10.15 cm diameter, Ks was greater than basic IR (ponded IR) for both initial moisture levels. Ks decreased with increased diameter and decreased with increased initial soil moisture.
In general, for point source infiltration, hydraulic conductivity, Ks did not change markedly with column/pot size for both levels of initial moisture ranging between 0.028 and 0.029 cm min-1 for initial moisture level L1 and 0.023 and 0.029 cm min-1 for initial moisture
level L2.
Point source IR determined for the 8.4 cm column (confined PS infiltration) and 41 cm pot (unconfined, 3-D, PS infiltration) were quite consistent with values of 0.007 and 0.005 cm min-1 for the column and the pot, respectively (initial moisture level L1). Corresponding values under L2 were 0.005 and 0.003 cm min-1. However, again, the 10.15 cm column produced markedly higher IRs.
For column sizes, 8.4 and 10.15 cm, ponding IR was generally higher than point source (PS) infiltration. Basic IR was also greater in ponding than in PS. Results indicate greater IR values as well as basic IR for the confined 8.4 column than the 41 cm pot unconfined infiltration. The boundary effect of column walls might be a reason for that.
Determined PS IR was greater for soil with lower initial moisture content (L1).
For unconfined disk source infiltration (41 cm pot), IR and basic IR were both greater for the initially dryer soil (L1). Also, disk source (DS) IRs were markedly greater than PS IR.
Parameter u, = IRbasic / Ks, varied greatly among treatments. The u ratio had two extreme values of 3.065 and 2.685 (10.15 cm column, ponding). Lowest u values were associated with PS and DS infiltration. Calculated average u were 0.424 and 0.374, for L1 and L2, respectively. If a single u parameter value is sought, it appears that values associated with 60 the unconfined 3-D, DS infiltration (the 41 cm pot) could provide a physically meaningful
value. These values are 0.270 and 0.162 for L1 and L2, respectively.