Problems With the Water Table From a Seismic Survey

A seismic survey is a geological tool that utilizes refraction and magnetic measurements to monitor occurances such as bedrock elevation and water table depth. Seismic surveys assess the quantity and quality of groundwater sources and the information obtained provides insight into the effects of drought, groundwater pumping and mining on the water table.

Groundwater

• Groundwater is possibly the most important resource across the globe; it not only serves a function in agriculture and industry, it is a primary drinking supply in many countries. It is also in increasing demand as water resources are overstretched due to unsustainable use. Thus, monitoring its availability and quality levels are essential.

Seismic Surveys

• Seismic surveys generate and measure the refraction of subsurface waves as they increase in velocity. Wave velocity increases as bedrock density increases across the water table, moving from unsaturated to saturated material. This measurement also gives information on rock permeability. Subsurface waves increase the risk of damage to underground water wells, particularly ones that were constructed poorly. Groundwater is subsequently analyzed to see whether the survey impacted on water quality.

Rock Permeability and Water Table Depth

• As seismic surveys also measure the permeability of bedrock, they are able to determine which areas of the water table contain nonporous material that may block groundwater flow, causing some locations to have considerably lower water table levels than others. This is useful to know when making decisions on where to build water wells or groundwater pumping sites.

Water Table Contamination

• Seismic surveys are able to predict what locations along the water table are susceptible to contamination. With data on water table elevation, the direction of groundwater flow can be determined, and it can be seen whether any contamination sources are present along its path such as a major road or an animal farm.