Groundwater is water that is beneath the ground and pooled in spaces between soil particles and rocks in the saturated zone. It’s always moving because gravity says go downhill, so off it goes by following pressure, looming way beneath homes, offices, trees, and into lower ground.
It moves faster still, depending on what lies below. Sand and gravel are essentially a big open-pored sponge, making it easy for water to move. Clay has pores that are much smaller and therefore moves groundwater less rapidly. Because fractured rock is unpredictable, it may move water very fast through cracks even though the same fractures create the impression of solid material.
This is so important because pollution frequently comes together with groundwater. If substances akin to gasoline, solvents, or dissolved metals enter the air, water, and earth environment, these might move along the same paths. This can eventually lead to a “plume” – a long, narrow band of contamination that travels from the original site. For Groundwater Remediation, contact https://soilfix.co.uk/services/groundwater-remediation/
Contamination doesn’t always spread evenly. Others are more soluble and travel in a dissolved plume. Some contaminants, including some fuels and oils, can float on top of the water table or be lighter than water, in which case they flow over a longer-term source that leaches pollutants at very low rates.
Seasonal and longer-term changes in direction are not unusual; however, fluctuations in rainfall may cause the level of a nearby stream or pond to change significantly, which diverts groundwater from new directions. Local dewatering caused by construction projects can cause groundwater levels to drop appreciably, thus causing flow paths that did not previously exist.
For this reason, groundwater investigations are more about looking for flow direction and understanding the geology rather than providing clear-cut results from one monitoring spell. If we know how groundwater flows, we can predict where a plume of contamination might go next and use an appropriate method to remediate it.
