Momentum of flow in soils assessed with TDR-moisture readings

Momentum dissipation due to viscosity during flow in soils is assessed with TDR-measurements during and shortly after infiltration. One field example demonstrates that about 30% of the momentum applied to the soil surface during infiltration is used to drive flow along presumed macropores to the 0.3-m depth, that 90% of the momentum arriving at this depth is used to drive water further, and only about 10% of it is used to distribute water locally into the finer pores. Other examples on a different soil demonstrate the applicability of the approach. The amount of momentum transfer from the surface to some depths in soils is proposed as a measure for quantification of macropore flow.