What function does an observation well serve?

An observation well primarily serves the function of measuring groundwater levels and quality. These wells are specifically designed to monitor the groundwater system's dynamics, including fluctuations in water levels due to seasonal changes, climatic variations, or human activities such as pumping. By providing data on both water levels and quality metrics (like pollutants or salinity), observation wells are crucial for understanding aquifer health, managing water resources, and ensuring sustainable use of groundwater.

While other options might touch on aspects of water management, they do not accurately represent the primary purpose of observation wells. Storing water samples is not a function of observation wells; instead, samples are typically collected for analysis at different sites. Providing irrigation is not a function of observation wells either, as they are not designed to deliver water but rather to monitor it. Lastly, while preventing contamination of aquifers is a critical concern in water management, the actual prevention of contamination is not the role of observation wells but rather part of broader regulatory and management practices. Thus, the primary role of observation wells in monitoring groundwater levels and quality is essential for effective water resource management.