Question

which action would best help prevent groundwater erosion?
using breakwaters
packing down soil
building drains with outlets
increasing the slopes of riverbanks

Explanation:

• Using breakwaters: Breakwaters are used to prevent coastal erosion (wave action), not groundwater erosion. Eliminate this option.
• Packing down soil: Packing soil compacts it, but it doesn’t effectively address groundwater movement causing erosion. Groundwater erosion relates to water flow through soil, and packing alone doesn’t manage that. Eliminate this.
• Building drains with outlets: Groundwater erosion occurs when water moves through soil, carrying sediment. Drains with outlets help redirect excess groundwater, reducing its flow velocity and ability to erode soil. This targets the cause of groundwater erosion.
• Increasing the slopes of riverbanks: This would likely increase surface water erosion (e.g., from rivers) and could worsen instability, not prevent groundwater erosion. Eliminate this.

Answer:

C. building drains with outlets