Excavating the West Lawn Bottom Zone, Part 3

More digging.

 Extending the Retaining Wall.

Digging up to the back yard patio sidewalk, to begin laying down the other end of the River of Rocks.

We need to find proper height rocks to extend the Retention Wall over the excavated path, and then put the River of Rocks over them.

While we were working on this, the Fall rainy season arrived.  At one point we got 5 inches of rain, which flooded the pit that we've excavated.

And then five days later, we got 8.5 inches, flooding it again, and even higher.

The result is that it is too wet to work.  The dirt is very heavy and sticks together; I think this is from a high clay content.  After two weeks, it's difficult to dig, but possible.  I used this time to finish the Retaining Wall and link it in with the beginning of the River of Rocks by the back sidewalk.

Water Supply for Zones 6 and 7

We saw some weeks ago that irrigation zones 6 and 7 had valves in the middle of what is now the West Lawn Bottoms.  We dug these up and found that they had a common water supply line heading back towards the house.

We removed these lines and capped it off, and then extended the Retention Wall up to where the water supply line was capped off.

Both Zone 6 and Zone 7 will be for the lawn sections below the Retention Wall (Zone 8 is above the Retention Wall), so we need to bring them thru the Retention Wall. 

First we dug back to discover where the water supply line comes from.  It turned out to Tee off the main irrigation water supply line.  The main irrigation water supply line is a 1 1/2 inch PVC line running, in this section, parallel to the back of the house -- about 31 or 32 inches away from the foundation of the house.  The Tee for zones 6 and 7 is 72 to 74 inches West of the corner of the house (next to the Iris Garden).  We replaced the schedule 20 PVC with schedule 40 PVC.

We then ran the line down to the Retention Wall, dropped it down (since the ground is sloped down)

and then we ran it thru where the Retention Wall will be and reattached the valves for Zone 6 and Zone 7.   We taped the electrical control wires to the bottom of the PVC pipe.

This positions them to be used for irrigation lines to service what will some day be the lawn part of the West lawn, and the Central Lawn area.

The main lines are 1 1/2 inch lines.  They are stepped down to 1 inch lines for the valves.  The valves have 1 inch input and 1 inch output.  We will probably step that down to 3/4 inch lines with 1/2 taps for each sprinkler head.

Excavating the West Lawn Bottom Zone, Part 2

For the past month plus, we have been continuing to dig out the Bottom of the West Lawn while extending the Retention Wall and filling in behind it with the dirt excavated out of the Bottom.

We continued with the digging.  Both next to the Jungle,

and next to where the Retaining Wall needs to be extended.

Until, at one point, I hit a main irrigation line taking water to the control valves for Zones 6 and 7, which have pretty much been taken apart.

and once the valves have been found, we exposed the entire water supply line, and removed it, keeping the valves so they can be reused.

Continued digging exposed more and more rocks, big and small.

Some of these rocks were used to extend the Retention Wall.

Filling in Around the Tree in the West Lawn

The Stone Retaining Wall is part of the work to terrace the land around the big tree in the West Lawn.  The other part is along the fence.  If we raise the level of the lawn, we will need to keep the dirt off the (wooden) fence.  We have a base of concrete, with a stone topping along the fence.  We want to build that up, and level it, so that we can fill that area with dirt.

We begin putting down short courses of stone, to try to get it more level.

After about 5 courses of stone, we have it pretty level, almost all the way.

Still need a bit of work at the far end. 

But with it this well done, we can begin to fill it in.  We have a pile of dirt from the excavation of the Bottoms area.  We can use some of the bags of compost that we use for concrete framing -- some are falling apart.  And we bought a bag of peat moss, to try to encourage this area to hold water.

 To try to prevent the dirt from falling thru the cracks in the the retaining wall, we have stretched some weed barrier behind the wall before we start putting dirt against it.

A couple of days of just moving the dirt around and we have it partially filled in, beginning to take shape. 

As we continue to excavate dirt from the Bottoms, we can use it to fill and smooth this raised area behind the retaining wall, around the tree.

Rebuilding the West Lawn Bottoms

Excavating the West Lawn Bottoms is part of the solution, but we also need to put it back together.  If the Bottoms grass area is going to be (mostly) level, the stone work along the fence needs to be mostly level too.  It is currently far from level, it slopes down with the fence and the original slope of the land.

And making the side stone work level will require another course of stone work along the border between the Bottoms and the Blue Rock Pool.  Two trips to Whittlesey Landscape Supplies gets 720 pounds of rock ($62.35).

which we can mortar into place.

We will probably need to continue the stone work, but for now we have a start on that, let's look at the larger picture of what we have excavated.

We have a lot of large stone pieces, and we want a stone retaining wall along the left of the above picture, to hold the dirt back around the base of the Oak tree.  So we will stack the rocks that we have, to form a stone retaining wall.  After a day of trial and error, we have a start.

Now we need to dig out more rock, to continue the wall, and dirt, to fill in the pit in front of the wall.

Continuing on this digging, we move all the dirt over out of the way, and continue to dig away.  That exposes a large rock in the lower left corner of the photo below.

Further work exposes the entire piece.

It's much too large to work with, so we break it down into four pieces.

And we can use those rocks to extend the retaining wall.

Excavating the West Lawn Bottom Zone

We want to install a retaining wall, to level the dirt level in the West Lawn both for the big live oak tree and for the River of Rocks as it comes around the corner of the house and heads to the back deck.  The area between the retaining wall and the Jungle will be a lower level as a bed or grassy area, which, since it is at the bottom of the West Lawn, we will call the Bottom Zone.  I have tentatively outlined where I think the retaining wall will go.

We will want to excavate this entire area, so that there is plenty of good dirt for the roots of whatever we end up planting there (grass like the East Lawn, for example).  So we begin by digging up all the dirt, down to bed-rock.

This will take days or weeks.

Two days later, we have a start.  We have stripped the dirt off the top of the section near the fence.  We can not go too far down in a section, because of the French Drain that runs along the fence and ends in the Blue Rock Pool.

But once we are past that point, we can dig all the way down to rock.

On the left it's 17 inches to rock; on the right, it's 21 inches.  It's 8 feet from the left to the right.  All we have to do is extend this excavation to the East.  We have the first 9 feet done; only about 30 feet more to go.

I had almost forgotten how this is done.  First I dig a hole or trench to get down to the depth that I want to be at.  Then I can dig sideways by standing in the trench and extending it to the adjoining area.  For example, we start from this position, and expose a bit of the rock buried under the lawn.

We continue to remove the dirt from the rock, exposing more and more rock at the save level.

The dirt is mixed with leaves and grass and put in the wheelbarrow and taken away to be saved.  When the rock is all removed, the dirt is brought back.

As we did out the rock, there are smaller rocks.  These we put aside in a bucket until we have enough to wheelbarrow all of these smaller rocks around to the front for disposal.  We are trying to improve the soil quality by removing the rocks and adding organic material (leaves, grass, compost), as well as replacing the volume of the rock with better quality dirt.

 With enough digging, we can expose an entire rock.  Most of our rock is broken down into pieces smaller than the kitchen table, although occasionally we will get even larger pieces.  If the rock is too large to be rolled around, I will need to break it into smaller (large) rocks.

The result is a pile of large rocks (too large to lift, but small enough to be rolled around).

 and a pile of dirt which is put off to the side for later. We can get a big pile of dirt from these holes (fluffed up by leaves and grass and air).

A Larger Picture of the Bottom part of the West Lawn

The bottom part of the West Lawn is mainly dominated by the big live oak tree.  That and the turn of the River of Rocks, around the corner of the house and over to the steps coming down from the deck.

In trying to define the River of Rocks, it seems that this area slopes downhill quite a bit.  There are big roots for the live oak that run along the ground, and we have had a significant problem of dirt being eroded and washed down into the pool of blue rocks and the Bamboo Grove.

It appears to me that it can be significantly improved by putting in a terrace wall.  A terrace wall would allow me to add dirt to the base of the live oak tree, while at the same time keeping the ground mostly level.  There should be less run-off erosion with level ground.  And the River of Rocks would be able to decrease slowly from the corner of the house to the back deck, rather than decrease a lot and then come back up some.

We thought about building it from 6x6 limestone blocks, like we used for the raised garden, but Linda suggests using natural rock instead.  So we need to come up with a short rock wall of native rock.  A terrace wall of about 24 inches seems like it would work best.

This would partition the bottom part of the West Lawn into two pieces -- upper part around the base of the live oak, and continuing over to the River of Rocks, and a lower part that would stretch from the fence between the Jungle on one side and the terrace wall on the other back to the center of the back yard.

This tongue of yard should be fairly level, from side to side instead of it's current slope down.  We have already excavated the part closest to the fence, but will still need to dig down for most of it.  If we encounter the rocks that we would expect, as we have found in the rest of the yard and in the part near the fence, we should be able to use those big rocks for the terrace wall.  And we need the terrace wall to define the level of the soil behind it, from the terrace wall  around the live oak tree and back up to the main West Lawn.  And we need that level before we can put in the irrigation lines for this section (Zone 8).

So it seems this is the next part of the yard to dig up.  Then define the terrace wall.  Then fill in the ground behind the terrace wall.  Put in the new Zone 8 irrigation lines and heads. Then continue the River of Rocks around the corner of the house to the deck sidewalk.

The Old Irrigation Zone 8

Zone 8 of the irrigation system is sort of the area of the West Lawn.  We are going to re-purpose it so that it is specifically the West Lawn, west of the River of Rocks.  Zone 9 will take care of the beds between the River of Rocks and the house.

All of this area is supposed to be put over to native, drought-resistant, shade tolerant plants.  I think it is sedges and native grasses.  The landscape plan says it is 11, 12, and 13 which are horse herb/wedelia, meadow sedge/texas sedge, and inland sea oats/chili pequin.  I'm assuming that all these have the same watering needs, so I intend to run one line of heads next to the fence, spraying in to the yard, and another line of heads next to the River of Rocks, spraying the other way, so that we cover the entire area.

So the first problem is to remove the old Zone 8 piping.  It seems to go every which way.  Turning on Zone 8 and marking which heads pop up shows a couple along the fence, one by the corner of the house, and a couple in the middle of the yard.  We want to remove all of these, and (eventually) replace them with new piping and heads.

We start with one of the heads.  Dig down and see where the piping is.

We dig along the pipe across the yard, until we get to the River of Rocks.

At this point, it would appear that it runs to a line that runs next to the main irrigation water supply line, which we don't want to disturb, so we cap this line off.

and go on to repeat this for the other heads.

The next group of heads leads us back to the Zone 8 Valve.

which we dig up carefully.

We can see that it is nestled in the turn of the main irrigation supply line.  The main must be one-inch PVC.  Zone 8 taps off of that and sends water in two directions -- one small pipe (1/4 inch) towards the corner of the house, a larger (1/2 inch) pipe goes back to the main supply line and tees into one line going along the main (this is the one that we have capped off all its heads), and another that continues across the yard (which is the one we followed back to find the value).

So we need to dig up this last head for Zone 8, and then clip the existing lines off and attach the lines that will define the new Zone 8, with sea oats and sedges.

As we were digging up the last sprinkler head and PVC line for Zone 8, we had the problem that the Zone 8 line was positioned next to the main irrigation water supply line.  So naturally, we put our pick axe thru the main supply line.

You cannot patch these lines; you have to replace this part.  But replacing a small piece in the middle of an existing line, with both ends fixed in place, is difficult to impossible.  So I replaced a much larger piece, from where the break was down to the corner and up a piece from there.  This includes the section that provides water to the Zone 8 valve, and we decided to move the Zone 8 valve to the outside of the main supply line, instead of it's previous position inside the main supply line.

We replaced the previous Schedule 20 PVC with Schedule 40 PVC, which has much thicker walls.

The main irrigation water supply line is 1.5 inch PVC.  The lines going into and out of the Zone 8 valve are 1 inch PVC.  We will probably end up with two 3/4 inch lines going from the Zone 8 valve, and then step those down to 1/2 inch for the actual heads.

But for now, we are done with this section of the West Lawn, and so we can cover the irrigation lines over, remembering where the Zone 8 valve is, so we can come back to attach to it later.