Which practice helps mitigate saltwater intrusion in coastal groundwater?

• A. Building new coastal desalination plants.
• B. Increasing pumping from wells.
• C. Implementing managed aquifer recharge and reduced pumping.
• D. Constructing seawalls.

Answer: (C)

Saltwater intrusion happens when groundwater in coastal aquifers is drawn down by pumping, lowering the freshwater pressure and allowing seawater to move inland. The most effective mitigation combines increasing the groundwater’s pressure and reducing withdrawals: managed aquifer recharge adds water to the aquifer during times of surplus, raising the hydraulic head and expanding the freshwater lens, while cutting pumping slows or stops further decline of the water table. Together, these actions address both supplying the aquifer and limiting stress on it, which directly counters intrusion. Building new desalination plants provides more fresh water but doesn’t directly restore aquifer pressure or prevent seawater from moving in; increasing pumping worsens intrusion; seawalls protect shoreline but don’t solve groundwater balance inland.