The time rate of settlement of coarse-grained and fine-grained soils is different. Free draining, coarse sand and gravel with fines <5% generally have good drainage qualities (high hydraulic conductivity), so any excess porewater pressure developed by loading can easily dissipate relatively (relative to fine-grained soils) quickly. Thus, most of the settlement of these soils occurs during construction. Fine-grained soils have poor drainage qualities. Excess porewater pressures developed during loading can take decades to dissipate.