Lecture 16 Soil Water (3)

1. Lecture 16 Soil Water (3) Soil Water Movement (2) Infiltration and Capillary Rise • Effect of texture on infiltration • Soil water redistribution • Capillary rise

2. Infiltration Process of water entry into the soil through the soil surface. It is an important process affecting water absorption by soil and runoff during rainfall events.

3. Terms to Remember Infiltration rate: water entry through the soil surface per unit time, e.g., mm/h Infiltration capacity: the maximum infiltration rate that the soil system can sustain. In a storm event, it is important for determining the partition between absorption and runoff. It decreases as the soil gets wetter. Infiltration

4. Infiltration Capacity Figure 6.10, WR

5. Soil water movement during infiltration Figure 6.11, WR Infiltration

6. Soil water redistribution after infiltration Figure 6.14, WR Infiltration

7. Soil water movement during infiltration Figure 6.12-13, WR Infiltration

8. Capillary Rise Definition: upward water movement due to capillary tension Figure 6.16, WR

9. Terms to Remember Capillary tension: Surface tension at the interface between soil air and soil water Capillary rise: upward movement due to capillary tension Capillary fringe: saturated zone above the water table due to capillary tension. Rate of capillary rise: macroscopic upward water movement due to capillary effects per unit time, i.e., mm/h Maximum rate of capillary rise: depends on water table depth and soil texture. Capillary Rise