Drill and Fill can lead to improvements in saturated hydraulic conductivity by 40% or more   (Canadian Turfgrass Advisory Group)

Accumulations of organic matter and fine soil or sand particles and layering are the most destructive changes that can occur in sand capped push up greens or sand based root zones.

Management programs and purchasing typically evolve in a minor way through each annual cycle, each minor change can compound over a number of years leading to a major change and a potential catastrophe in season or through the overwintering process. 

As such, putting green soil/sand chemistry and physical properties (hydraulic conductivity and infiltration) and topdressing laterals should be benchmarked through testing annually. 

The accumulation of the testing data (chemical and physical) is crucial to evaluating the success or failure of all management (cultural, fertility) programs but more importantly, is a critical piece to selling or reinforcing the return on investment in key renovation events such as the Drill & Fill to members and or ownership.