When large amounts of water are extracted without timely replenishment, this can press the soil particles tightly together. The soil loses its ability to support the stratum above it and collapses or subsides. Once the spaces separating the soil particles are compressed, it is very difficult for them to expand again. At the same time, space available to store water in the aquifer is reduced.
當水分大量抽取、補注不及時，會使得土壤顆粒壓密，無法支撐上方的地層而下陷，尤其阻水層土粒間空隙一旦壓密就難以恢復，同時含水層也減少了可供儲水的空間。