Lowering the Main Irrigation Water Supply Line

Back in November, 2012, we excavated the East side of the backyard.  As part of that, we exposed the main irrigation water supply line, and to make sure it was well out of the way, we lowered it all the way down to the bedrock.  We had to raise it back up to interface with the existing pipe where we were not (yet) digging.

Now we are digging back to that point, from the other direction.

And today, we dug all the way over to where the pipe drops.

The objective is to dig out all the dirt and rock under the existing pipe, down to bedrock, and then re-do the linkage to the pipe on the East side to lower this section that goes along the center of the yard.

More digging exposes not just the main irrigation supply line, but also the line for Zone 5, and an old (unused) PVC line (which we have now removed).

 Using the jack hammer to break up and remove the rock that has been exposed, we can excavate all the way down to bedrock.

Looking at the far end of the trench shows how the previous work had to "step up" to connect with the un-excavated main supply line:

The first step is to remove all the old PVC pipe.   Then we lay new PVC pipe and couple it directly into the main water supply line. ($34.38 at Home Depot for PVC pipe and pieces).

This is a new 1.5 inch Schedule 40 PVC pipe.  It runs along the ground until it gets to the valve for the Zone 5 beds.  At that point we "tee" off to a 1 inch PVC line going up.

We continue along at ground level until we get to the end of the pit, next to the end of the River of Rocks.  At this point, we must once more "step up" to connect to the rest of the (unexcavated) main water supply line as it continues around the house.

Since both ends of the pipe are fixed, we have to do something to finish the last connection.  We used an NDS 1.5 inch Pro-Span Coupling, which cost $20.65.

From the valve box for Zone 5, we ran 3/4 inch PVC back to the Iris bed and to the Herb bed.

Since this was only 3/4 inch PVC, it was more flexible and we were able to use standard couplings.

Update, May 2017.  The joint at the bottom of the vertical gave way sometime this month and leaked enormous amounts of water.  Eventually, the water worked its way to the surface and I shut the main irrigation supply line off, dug down and found the problem.  I then replaced the bottom elbow fitting (and several other adjacent pieces) to fix the problem.

But it really did a number on our water usage.  Here's the water usage for the past year, from the May bill.

Normally, our usage would be about 4000 gallons; because of the leak we used over 20,000 gallons.

Digging up the Central Backyard, Part 1

With the wall around The Jungle finished, we can turn our attention to excavating the Central backyard.

We start by continuing the work that was necessary to do the wall, particularly digging all the way to previous work, behind the Jungle and up to the fence.

This is pretty simple work -- dig down to bedrock, separating the rocks (which we haul off) from the dirt.  Mix the dirt with leaves to increase the amount of organic material in the dirt.  Put the dirt to the side, out of the way of more digging.

 
We can't dig too far to the left, since we need a pathway to get from the house to the compost pile behind the Jungle.  So we chip away at the edge of the yard

until we realize we need to be more organized about this.  That leads us to draw a couple of lines on the ground.

and we will take off all the dirt to the right of the line, up to the sidewalk, and then start digging across the yard, next to and parallel to, the sidewalk.

all the way over to the yucca plant and the part of the yard that is finished. This is roughly a rectangle 16 feet long and 10 feet wide.

With that decided, we can just start digging.  This takes all our tools -- shovel, hoe, rake, the barrels of leaves, and produces lots of rocks.

and day by day, we get more digging done.

This is exposing another layer of rock that we will need to take out.

Another day gets us all the way to the sidewalk.

Four days of digging, breaking up rock, and clearing it out, gets us to a more finished situation here.

Now we turn to dig across the yard.   First we dig one section.

and then widen that with another section.

and another.

until we have most of it dug up.  There is still a strip next to the sidewalk that is protecting the main irrigation water supply line.

And we stopped before going all the way to the finished lawn because we have hit a very large hole in the rock.  There is an area which was previously dug up where the shin oaks were before they were moved to the South-East corner of the backyard.  We moved them back in February 2011.  So this is a different type of yard to dig up from what we are working on -- dirt on top of rock.  In the section that is yet to be dug up, it should be just dirt.

So for this section, we start with a layer of rock.

and using the jackhammer, we reduce this to smaller pieces of rock.

A couple of days of cleaning up that leaves still a couple of large rocks

which again, with the help of the jackhammer can be reduced to more manageable chunks.

and then cleaning that up

leaves a big new clear area to continue work from.

Next we turn back to the strip going back to the fence.

Note the section to the left of the white PVC pipe, going from the corner back to the fence.  After a few days of digging, pulling out the rock, mixing the dirt with leaves, we have

Finishing the wall for The Jungle

We have a plant bed in the back yard which we call The Jungle.  It was originally developed back in the 1980s to keep some trees and to add some plants around it.  There were two types of plants: something and Nandina.  Over the years (decades), the Nandina has taken over, so it's just the trees and the Nandina, pretty much.

Nandina is a cousin of bamboo, and like bamboo, it likes to spread via its roots.  There is a short stone edging around The Jungle, but the Nandina spreads into the yard by going under the edging.  So as long as I'm digging up the yard anyway, I'm also putting a wall under the edging that goes down to bedrock, to keep the Nandina from getting out of The Jungle.

Previously I did the section by the Bamboo Grove, and by the Bottoms, so there is just one section left.

We dug out the yard around this edge of the Jungle, and kept digging until we hit the dirt that had already been excavated behind the Jungle.

Then we had to clean up the area under the edging -- cleaning out the dirt, the rocks, and the roots.

Then we framed it up to pour a concrete wall under the edging.

We only got half of the area filled the first day

so we framed up the second half and did that the next day.

That finished off the concrete.  It took 16 of the 60-pound Quikrete bags of concrete to build the wall, plus an 80-pound bag of Mason Mix to finish it off.

We used Mason's Mix to smooth off the wall surface and especially the interface between the stone edging and the wall itself.  Also to mortar in a rock in the missing part of the edging at the far left of the photo.

Digging up the Central Backyard

The East side and West sides are pretty well done now, so it's back to the central part of the backyard.

We have mainly been using the backyard as a staging location for the materials for our work -- piles of dirt, rock, and mulch.  But it is time for it to be the main focus of our work.

Our plan is to dig from the West and go down a couple of feet, mixing the dirt with more organic material as we put it back in place after removing the rock.

We begin at the edge of the work on the River of Rocks, first making sure that we know where the main irrigation water supply line is.

and then we continue removing the dirt from the layer of rock along this front.

and more digging.

and more digging.

This will continue for a while.  Let's see if a video can show what we do.

 

 Eventually, we dig all the way to the wall around the Jungle.

and then we start removing the rock, putting it up on the lawn, to expose ... more rock!

We can use the pry bar to separate out some of the larger pieces of rock,

but we will need the jackhammer to make them into small enough pieces that we can manage.  A day of work with the jackhammer:

followed by a week of moving rock and cleaning up the debris:

yields a new lower level for the yard and a yard full of large rocks which we will need to get rid of: