Hopefully you’ve found the prime location for your bubbling boulder oasis. If so, now you can start digging! While it’s not the most rewarding part of the job, it does give you a sense of accomplishment, and the feeling that it’s really happening.
Gather all the tools you’ll need.
Before starting any project, it’s best to think through which tools you’ll need. The below list should cover just about anything you’ll need to dig the pit:
- Durable Shoes
- Sun Hat
- Spade Shovel
- Square Shovel
- Loppers (for tree roots, if you have nearby trees)
- Measuring Tape
- Long Board
- Fluids (to stay hydrated)
Digging the pit takes time.
The pit I dug was about 6’ x 6’ x 18″-24” deep. (It was on a slight slope so the depth varied.) Subtracting breaks, digging time totaled 6-8 hours. It’s a great workout.
Okay … I just realized I’ve not explained WHY you even NEED a pit. When you read next month’s bubbling boulder post, or possibly the following month’s post, this will all make sense. For now, I’ll give a brief explanation.
For this boulder to be a bubbling boulder it must have water. For water to be present, and circulate up through the drilled hole(s) in the boulder, there has to be a place for the water to pool. The pit provides this.
The pit size depends on the boulder size and water flow volume.
As far as stating the size of pit you’ll need for a given boulder, I’m outside of my comfort zone and knowledge. I can only say what we did (see above measurements) for the size of boulder we have.
I’m guessing, if your boulder is small (about the size of 3 basketballs), the pit would need to be 3′ x 3′ x 10″-12″ deep. The pit depth should probably be a minimum of 10” deep for small boulders. The boulder will be placed on various blocks, which will be discussed in a future post.
The pit needs enough volume or cubic space to allow the water pump to circulate water WITHOUT the pit running dry, as the pump sends water up the boulder.
I made the pit walls completely vertical, but I don’t know that it has to be done that way.
Because of the steep ravines on three sides of our property, I was able to shovel the dirt/clay into the wheelbarrow and dump it down the ravine. I realize this is not a normal setup, so you’ll want to give some thought – ahead of time – as to where all the dirt will go. A berm is one idea to consider.
The bottom of the pit should be completely flat, with one exception.
On the back side of the pit (the side you won’t look at as often), dig one corner with an inch or two drop-down, sort of a separate pit. This is where the water pump will be placed. With this corner being lower than the rest of the pit, it will aid in the cleanout when you drain the pit before each winter.
The bottom of the pit should have a slight pitch leading to the water pump corner.
Use the level to make sure the pitch is subtle. Place a long board on the bottom of the pit, and then place the level on the board to check the slant. If you have to raise the level a lot to get the bubble in the center (which is where the bubble would be for a perfectly flat, no slant surface), then the slant is too much. Aim for about a ½ inch slope/slant for every 3 feet of length.
Always keep the construction area a safe area.
Be sure to place strong boards over the pit when you’re not working on it. You’d hate to come out the next morning and find the pit full of people who have fallen in, and are unable to climb out.
Below are links to the previous posts in this bubbling boulder how-to series: