Question

Seawater intrusion into coastal aquifers generally occurs when

• A. Recharge increases
• B. Pumping exceeds recharge
• C. Rainfall increases
• D. Storage increases

Hint:

Coastal aquifers: \[ \boxed{ \text{Over-pumping} \rightarrow \text{Groundwater level} \downarrow \rightarrow \text{Seawater intrusion} } \]

Answer 1

The Correct Option is B

Step 1: Picture the coastal aquifer balance.
Near a coastline, fresh groundwater and seawater sit side by side underground, held in place by the outward push of fresh water pressure.
Step 2: Think about what upsets that balance.
If wells draw out more water than natural recharge can replace, the freshwater head drops and its outward push weakens.
Step 3: See the result.
With less freshwater pressure holding it back, seawater moves inland into the aquifer, causing intrusion, unlike the other options which would actually strengthen the freshwater side.
\[ \boxed{\text{Pumping exceeds recharge}} \]