Monday, August 3, 2015

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.

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