Ponds 103 Chapter 2
Excavation
(Before we start, please note: “outwards” means ‘away from the center of the pond’, “inwards” means ‘towards the center of the pond’)
Using the water level stake as your guide, dig the Rock Shelf from the painted line outwards to 8” below the top of the stake and level the shelf all the way around. Make the Rock Shelf at least 6” wider than the widest rocks you’ll be using for the coping, wider still where you might be considering a perimeter bog along the edge of the pond. Remove the soil inwards from the Rock Shelf down to the same 8” depth and re-mark the line that you just dug out. You should end up with a shallow hole with the water’s edge still outlined on the bottom, with the water level stake sticking up 8” from the bottom, about 4” below existing grade.
Next you’ll remove another 10” of soil straight down, from the line inwards, to create the vertical sides down to the Plant Shelf at 18” below water level. The easiest way to get a nice straight drop is to remove the soil working from the middle of the pond outwards, carefully shaving the soil vertically the last few inches back to the line. Be careful shaping the soil edge of the Rock Shelf and don’t step anywhere near the edge as you’re working. If the soil does collapse or is too soft, gravelly or sandy to hold a vertical edge, simply lay in a ring of cinderblocks instead. No mortar is necessary, just set them level, fill them with soil and remember to pad the sharp edge of the blocks well, with an extra layer of underlayment. You should now have a broad, level shelf 8” down surrounding a vertical drop down to a flat bottom at 18”deep.
The flat “bottom” is the Plant Shelf, which you’ll want wide and flat for convenience and safety. Move inwards at least 24” all the way around and dig the pond down to its final depth of 24-30”. If you dig two pockets instead of one, you can create a “pond-within-a-pond” that will allow you to keep fish and plants safely submerged while the rest of the pond is cleaned. Go over the excavation carefully, removing any tree roots or “sharps”, as well as large stones, to leave the inside walls, shelves and floor as smooth as possible.
(Before we start, please note: “outwards” means ‘away from the center of the pond’, “inwards” means ‘towards the center of the pond’)
Using the water level stake as your guide, dig the Rock Shelf from the painted line outwards to 8” below the top of the stake and level the shelf all the way around. Make the Rock Shelf at least 6” wider than the widest rocks you’ll be using for the coping, wider still where you might be considering a perimeter bog along the edge of the pond. Remove the soil inwards from the Rock Shelf down to the same 8” depth and re-mark the line that you just dug out. You should end up with a shallow hole with the water’s edge still outlined on the bottom, with the water level stake sticking up 8” from the bottom, about 4” below existing grade.
Next you’ll remove another 10” of soil straight down, from the line inwards, to create the vertical sides down to the Plant Shelf at 18” below water level. The easiest way to get a nice straight drop is to remove the soil working from the middle of the pond outwards, carefully shaving the soil vertically the last few inches back to the line. Be careful shaping the soil edge of the Rock Shelf and don’t step anywhere near the edge as you’re working. If the soil does collapse or is too soft, gravelly or sandy to hold a vertical edge, simply lay in a ring of cinderblocks instead. No mortar is necessary, just set them level, fill them with soil and remember to pad the sharp edge of the blocks well, with an extra layer of underlayment. You should now have a broad, level shelf 8” down surrounding a vertical drop down to a flat bottom at 18”deep.
The flat “bottom” is the Plant Shelf, which you’ll want wide and flat for convenience and safety. Move inwards at least 24” all the way around and dig the pond down to its final depth of 24-30”. If you dig two pockets instead of one, you can create a “pond-within-a-pond” that will allow you to keep fish and plants safely submerged while the rest of the pond is cleaned. Go over the excavation carefully, removing any tree roots or “sharps”, as well as large stones, to leave the inside walls, shelves and floor as smooth as possible.
