Thankfully the water rill is easily drained to enable essential maintenance work. I also use boards to cover the empty water channel. A wise idea because I can become very focused on my trimming and don’t want to risk breaking a leg by stepping backwards into a rill.
The trimmed box leaves are easily sucked up directly from the boards using a garden blower/ vac.
This has been a beautiful design to work on, full of wonderful curves and challenging straight lines. I am nearing the end now and will post some photos when finished.