So first we take the rocks out to the curb. Line them up along the curb.
Then we put a notice on Craig's List and wait for people to come take them away. In this case, I put the notice up on Saturday. On Sunday, we drove my daughter back to college. In the four hours to do that (from 1 pm to 5 pm), all the rocks disappeared. All of them plus 4 or 5 that were to the left of the above picture, from our own rock garden.
Now the pit is empty. We have, occasionally over the past decade, had problems of things digging under the fence. Dogs, cats, possums, armadillos, skunks -- don't know what it was, we could just see the hollowed out area that they used. When we dug out the Bamboo Grove, we put a stone wall around it at ground level next to the fence. Since we have it all dug out, let us do that here too.
First we pour a cement wall down to bedrock. Just as with the bamboo grove, we use a 1x4 for spacing, and a piece of masonite cut down to eight feet by 16 inches for the framing. We stack up bags of dirt next to it to keep the framing in place. The bags of dirt are just mulch and compost plastic bags filled with dirt from the pit shovelled into them. This picture shows the result on one fence.
And here we see the process in progress on the other fence. When we were digging straight down from the fence, to get the back side of the cement wall, we hit a couple more rocks. In particular the really big one in the following picture. I was able to move it out with a pry bar, but it was too heavy to move. Before pouring the cement, I used the jack hammer to break it in two pieces and rolled them up the pile of dirt in the pit to the edge, then out to the front to take the place of a couple of our missing rocks.
It took 29 bags of cement (from Home Depot at $3.10 each), and 4 bags of mortar ($3.77 each) for this work. The limestone rocks for the top were left over from the previous work on the Bamboo Grove
Once the cement wall is poured, I can then mortar limestone blocks on top of it to finish it off. Once the dirt is back in the pit, all you will be able to see will be the top of the limestone brick, as an edging. It should keep things from digging under the fence, including animals and roots from trees or anything. It may make it easier to mow or edge the lawn.
It is not clear what effect it will have on drainage. In theory any rain in the yard will sink down and be stuck here, unable to soak under ground down the hill. But it's well away from the house, and I assume any plants in this area would welcome any extra water. (Plus, at the moment at least, any water can just go to the right and around the wall, since the wall is only at this corner (and the opposite corner, where the Bamboo Grove is).
This gives a pit about two feet deep and 16 feet by 24 feet. The next step is putting all the dirt that I dug out back into the pit. To increase the quality of the dirt, I will add compost and vegetation. Luckily it's now Fall, and the trees are dropping their leaves. I should be able to get bags of leaves from the neighbors to add to the dirt as I put it back in.
The bags of dirt from the Bamboo Grove that I used for the forms were mostly limestone rock dust, from when the utility trench was put in thirty years ago. Apparently when they are bagged up, get wet, and sit around for 6 months, they get hard and are not of much use. So I took them to the Travis County Landfill, $18.60. I had previously taken a load of loose rock out (another $18.60), but am now trying to get rid of the loose rock on Craig's List.