In soil science, for saturated soils or soils beneath the groundwater table,the effective unit weight is the difference between the total unit weight of the soil mass and the unit weight of water. Thus, the effective unit weight removes the effect of the pore water within the soil mass. One difficulty in its measurement is the determination of loosely held H₂O between clay layers vs H₂O between grains (i.e., pores).
Syn., buoyant unit weight, submerged unit weight.