Groundwater assessment is a practice in which aquifers are studied, mapped, and assessed for quality. This practice is usually undertaken by geologists and hydrologists. Government agencies commonly conduct groundwater assessments for the purpose of identifying additional sources of groundwater for human use, and such assessments may also be required before land can be developed, to confirm that there is enough water to support human activity on the land. Experts in groundwater assessment can work for the government, private consulting firms, and as independent contractors.
Groundwater is a critically important resource. The Earth may be covered in a lot of water, but most of that water is not accessible or usable. Groundwater resources are particularly thin because it can take a long time for groundwater to recharge, and groundwater supplies are vulnerable to pollution and overuse. Therefore, one of the key goals of groundwater assessment is to provide protection to ensure that groundwater is not overexploited and that communities understand that importance of guarding their groundwater.
Groundwater assessments typically start with a general survey which can include documentation from prior surveys at the site, aerial surveys, and surveys conducted on foot. The survey is used to create a complete picture of the aquifer and the surrounding environment, so that people can learn about the context in which groundwater is occurring. During the survey, people may attempt to identify a recharge point, look for areas where groundwater reaches the surface, and identify wells and springs which are already active.
Part of the surveying process includes a determination of how much an aquifer holds, and how much water can safely be removed before the aquifer will be compromised. Software modeling is often used for this, to create a picture of the aquifer and play with different potential scenarios. This calculation can get very complex, as different types of use can impact an aquifer in different ways. For example, an aquifer may be able to withstand a very high rate of use, but people in the higher areas of the aquifer would run out of water quickly, meaning that the rate would need to be restricted to ensure that people of all elevations could access water.
The practice of groundwater assessment can also include evaluation for water quality. Groundwater contamination is a concern because it can pose a threat to human or environmental health, making the identification of contamination and its sources very important for people who work with groundwater. If water is contaminated, the groundwater assessment will be used in the process of developing a groundwater remediation plan.