Final answer:
The sentence should include a comma for clarity: "Groundwater comes from underground reservoirs called aquifers, and we rely on these sources to meet half of our water needs in the United States." Groundwater is stored in aquifers and provides a critical source of water for drinking, irrigation, and maintaining surface water flows.
Step-by-step explanation:
The sentence requires a comma to separate the independent clause and the phrase that follows it, which provides additional information about the subject. Hence, the correct punctuation would be: "Groundwater comes from underground reservoirs called aquifers, and we rely on these sources to meet half of our water needs in the United States."
Groundwater is a significant source of fresh water for many communities. It is found in the spaces between particles in soil and fractures in rocks, known as aquifers. These aquifers are not only vital for providing drinking and irrigation water through wells but also play a role in maintaining the flow of streams and lakes.
Despite being a plentiful resource, they are susceptible to depletion and contamination. Therefore, protecting groundwater quality is essential, considering that a large portion of the population depends on it for their water supply.
The correct punctuation to use in this sentence is a semicolon