Drill and Fill

We've recently begun a manual drill and fill process on poorly draining areas of greens, specifically on the PG, #2, and #8.  We're drilling to a depth of roughly 16" using a 1" drill bit.  We made the boards using 3/4" plywood with the holes on 3" centers.  The channels created are then back filled using dry sand.  Although very time consuming we think these areas will benefit greatly from the process.  It helps to alleviate compaction, improves water movement, increases oxygen levels and gas exchange while breaking up any layering that may have occurred and creating a good growing medium for roots.