Surface waters are also affected by falling water tables. In various wetlands, for instance, the water table is essentially at or slightly above the ground surface. Dropping water tables results in wetlands drying up, with the ecological results described earlier. Further, as water tables drop springs and seeps dry up, diminishing streams and rivers even to the point of dryness. Thus, excessive groundwater removal leads to the same effects as the diversion of surface water.

Over the ages, groundwater has leached cavities in the Earth. Where these spaces are filled with water, the water helps support the overlying rock and soil, but as the water table drops, this support is lost. Then there may be a gradual settling of the land, a phenomenon known as land Subsidence

Another problem resulting from dropping water tables is Saltwater intrusion. In coastal regions, springs of outflowing groundwater may lie under the ocean. As long as a high-water table maintains a sufficient head of pressure in the aquifer, there is a flow of freshwater into the ocean. Thus, wells near the ocean yield fresh water. However, a lowering of the water table or a rapid rate of groundwater removal may reduce the pressure in the aquifer permitting saltwater to flow back into the aquifer and hence into wells.

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