A well’s capacity is determined largely by which factor?

The capacity of a well primarily depends on the well diameter because a larger diameter allows for a greater volume of water to flow into the well from the surrounding aquifer. This increased flow area enables the well to deliver more water per unit of time, which is a critical component in assessing how much water can be sustainably extracted from the aquifer. The water enters through the well screen, and when combined with a larger diameter, the overall capacity to supply water increases significantly.

While well depth, water quality, and well screen size are all relevant factors affecting a well's performance, they do not directly influence the well's capacity as much as diameter does. For instance, well screen size affects the filtering of sediments and may influence the quality of water obtained, but it does not have as strong an impact on the total volume of water that can be drawn from the well as the diameter does.