Final answer:
The removal of groundwater from aquifers in the plains states of the U.S. can have long-term effects on the hydrologic cycle, including the depletion of surface water resources and the intrusion of saltwater into freshwater aquifers.
Step-by-step explanation:
The removal of groundwater in the plains states of the U.S., such as Kansas, Nebraska, and Texas, has led to a significant imbalance in the hydrologic cycle. When groundwater is pumped from aquifers, it creates a localized drop in the water table, which is known as a cone of depression. Over time, widespread pumping of groundwater can result in a regional drop in the water table, affecting rivers, lakes, and reservoirs. This depletion of groundwater can have long-term effects on the hydrologic cycle.
One long-term effect is the depletion of surface water resources. When aquifers are overpumped, rivers, lakes, and reservoirs connected to those aquifers can also experience decreased water levels. For example, the Colorado River in the U.S. and the Yellow River in China have been known to run dry in some years due to excessive water withdrawals.
Another long-term effect is the intrusion of saltwater into freshwater aquifers near coastlines. When fresh groundwater is overpumped, it creates a cone of depression that can change the direction of regional groundwater flow. This can lead to the intrusion of saltwater from the ocean into freshwater zones, making the groundwater unsuitable for drinking or irrigation.