Question

The amount of groundwater is estimated to be \(\underline{\hspace{1cm}}\).

• A. nearly equal to the amount of surface water on the planet Earth
• B. less than the amount of surface water on the planet Earth
• C. twice the amount of surface water on the planet Earth
• D. twenty five times the amount of surface water on the planet Earth

Hint:

Remember the freshwater distribution: most is frozen in ice caps (\(\sim\)69%). Of what's left, almost all of it is groundwater (\(\sim\)30%). The tiny fraction remaining (\(\sim\)1%) is the surface water in lakes and rivers that we see and use most often.

Answer 1

The Correct Option is D

Step 1: Compare the major reservoirs of Earth's freshwater.
The vast majority of Earth's water is saline (in oceans). Of the small percentage that is freshwater, most is locked up in glaciers and ice caps.

Step 2: Compare liquid freshwater reservoirs.
Of the liquid freshwater, the two main reservoirs are groundwater and surface water (lakes, rivers, swamps, etc.).

Step 3: Estimate the relative amounts.
Groundwater constitutes approximately 30% of all freshwater on Earth. All the surface freshwater (lakes, rivers, etc.) combined constitutes only about 1.2% of all freshwater.

Step 4: Calculate the approximate ratio and evaluate the options. The ratio of groundwater to surface water is roughly 30% / 1.2% \(\approx\) 25. Therefore, the amount of groundwater is approximately 25 times the amount of surface freshwater. Option (D) correctly captures this significant difference in magnitude.