We've got this small concrete pond that we wish to fill in to make a flower bed.
The pond is 60cm deep at one end and 30cm at the other.
It currently has two 1cm holes in the bottom of it, which has been enough to keep it from filling with rain water over the winter.
My approximate plan is to fill it with whatever rubble or gravel I can get my hands on, and then the top 15cm with soil.
But my concern is drainage. Even if I drill more holes in the bottom, won't soil eventually wash down and fill up those holes? What can I do to make sure it doesn't start filling with water?