Offending sprinkler found

After the water meter box flooded we started running experiments to try to find out the cause. I have a tendency to experiment systematically I guess.
1. Operate the house water (showers, washing machine, etc.) with no irrigation.
2. #1 + Run the back irrigation only.
3. #1 + Run the front irrigation only.

We have not been able to recreate the leak. In between experiment #2 and #3 I dug a hole to the dirt behind our brick mailbox at about the same slope as the water meter box. My thought was that if the water was seeping from the ground into the hole due to our water table then theoretically it would in this second hole as well. It was just a dirt space so I figured it was worth a shot. No water in either hole through the experiments.

So today, since the baby actually took a nap, I figured I would run the front irrigation and take a look. There are two sprinklers in the plant area but only one works. The one that works is actually a lawn sprinkler and puts out too much water for that area. It is the one closest to the water meter box so that may be part of the problem. I think the majority of the problem is actually the other sprinkler that does not work.

It spurts water as pressure builds up in the system and it bubbles out. But once the sprinkler rises completely up the water stops coming out of the sprinkler. I dug around the offending sprinkler and found water building in the space around it, highly suspect. The view to the right was after I already chopped back that bush. It was an old growth bush that needed to go anyway. It is now in pieces on our driveway.

In order to get the sprinkler out of investigate it more, I had to remove the whole bush. The root system was the tricky part. Every time I dug my spade in I hit another root that I would have to excavate so that I could cut it back. A round tip shovel gave way to the narrow tip irrigation shovel which gave way to a hoe. I could only get down an inch or two before I would hit roots and clay. By the end of it, I had made a mess again but I didn't feel like I got much accomplished. There were decorative rocks and natural rocks to deal with in addition to the root system. Then there was an outpouring of ants; apparently I disturbed a colony.

Oh and the purple shovel is there because the baby decided she wanted to "deg deg" too.

When Mike got home he had a chance to help me dig. I had noticed the sprinkler head was loose and he discovered why. The sprinkler actually met a 90 that attached to another 90 then to another pipe. Given the direction of that other pipe we think it goes under the driveway or just up against it. We took it all off since it was loose and leaking anyway. We hit Home Depot and got a cap for it so that we can run the irrigation while we work on the area. Mike wants to put a smaller sprinkler on there and possibly dig up the mystery pipe a little more.

The other, active, sprinkler we will also replace with a smaller sprinkler. We hope that by repairing the leaking connections and using two smaller sprinkler heads, we've fixed the problem. Since we have been unable to reproduce the leak we still don't know for sure what caused it. Until it happens again though, we think we've located it.