Which of the following best describes the term 'filter pack'?

The term 'filter pack' is best defined as clean sand or gravel specifically used in the context of well construction and groundwater extraction. Its primary purpose is to support the well screen and prevent sediment and particulates from entering the well, which could otherwise clog the screen and disrupt the water flow. The filter pack acts as a barrier, allowing water to flow in while blocking fine sediments, thus maintaining the efficiency of the water extraction process.

Having a properly constructed filter pack is crucial for the longevity and functionality of a well, as it helps to ensure that only clean water is drawn into the system. This component is essential in various groundwater applications, including monitoring wells and production wells, where the quality and clarity of the extracted water are paramount.