Place these events in chronological order based on causality.
(4 ?items)
(Drag and drop into the appropriate area)
The level of the water table drops.
Groundwater is rapidly removed from a system.
Subsidence occurs over a broad region.
Pore collaphe takes places
First Event
Last Event
The correct answer and explanation is:
Chronological Order of Events Based on Causality:
- Groundwater is rapidly removed from a system. (First Event)
- The level of the water table drops.
- Pore collapse takes place.
- Subsidence occurs over a broad region. (Last Event)
Explanation :
The sequence of these events is dictated by the interactions between groundwater systems, soil mechanics, and geological structures. Here’s the step-by-step causality:
- Groundwater is rapidly removed from a system: This is the initiating event. When water is extracted at a rate faster than it can be naturally replenished, it creates an imbalance in the groundwater system. This removal is often due to human activities like agricultural irrigation, industrial use, or urban water demands.
- The level of the water table drops: As groundwater is extracted, the water table—the upper boundary of the saturated zone—starts to decline. This reduction signifies that less water is available to support the structural integrity of the subsurface layers.
- Pore collapse takes place: The water within the pores of soil and rock exerts pressure that helps maintain their structure. When the water table drops, this pressure decreases, leading to pore collapse. This means the tiny spaces within the soil or rock lose their structural support, causing compaction.
- Subsidence occurs over a broad region: The collapse of pores and compaction of soil lead to land subsidence. This is the sinking or settling of the Earth’s surface over a large area. The extent and severity of subsidence depend on factors like the type of soil, the depth of groundwater extraction, and the rate of withdrawal.
Understanding this sequence is vital for mitigating the risks of subsidence, such as infrastructure damage, reduced land usability, and environmental degradation. Sustainable groundwater management is key to preventing these cascading effects.