By Ken Rock, Virgin Valley Water District General Manager
On Friday evening, June 15, the 12” diameter PVC pipe under White Rock Road began profusely leaking. Fortunately this was repairable by isolating the line, then cutting out and replacing a relatively short section of the pipe. Nobody had their water supply interrupted because the water system has other interconnections below this area that allowed the crew to just shut off the water from the storage tank above and below it. The repair was completed that evening, and the hole backfilled for traffic safety.
Sunday morning, June 17 at around 3:30 AM a 10” PVC pipe below Palmer Lane failed catastrophically, with a lengthwise split along a 20’ section of pipe. By about 4:30 AM when our crew shut off the valve for this line, roughly a million gallons of water had been lost via a gaping hole in the street.
Often we let contractors bid on repairing such large breaks, but in this case the circumstances were weighed, and our crew immediately began pumping out the pool to dig in. Only a handful of houses were out of water that Sunday morning, and their service was restored by about 11:00 AM when a new section of pipe was installed. VVWD field workers continued working through the hot day to re-fill and compact the hole and put in traffic control markers, finishing at about 2:00 PM. Although one lane is now temporarily closed, traffic can safely travel on this street. Golf carts can cross Palmer Lane here as they previously did, but should proceed cautiously due to damaged asphalt at the edge of the road.
On Monday morning our Inspector met
with the City Inspector, and they marked the area of heaved and sunken pavement for replacement.
We’ll clean up the residual road dirt that was washed out of the hole.
For repaving this area and the smaller hole on White Rock Road, we will put together a notice for bids asking for a rapid response.
It will go out to all of the local contractors who have previously responded to our requests for bids.
You can expect this piece of road to be the freshest and smoothest around within a couple of weeks.
Neither break was on a line that sees pressure spikes. Both were heavy-walled PVC pipes. It appears that both were caused by rocks in the pipe bedding material, although the wash-outs remove most of those rocks, and often all we can see is small dents in the pipe. As happened under White Rock Road, sometimes the result of a pressure point is just a hole. In other cases, as the one in Palmer Lane, the result is a longitudinal crack from rapid crack propagation (RCP) that splits the entire stick of pipe. We haven’t lost our faith in PVC pipe for here, because it is so resistant to corrosion. We are getting significant reinforcement of the importance of diligent inspection and compliance with our pipe bedding specifications for pipe to be accepted into our system.
This weekend the crew also replaced 2 leaking laterals - none of which were Vanguard pipe. It was not a relaxing Fathers’ Day weekend for the field personnel! I’m proud of their responsiveness, skill and dedication, as I’m sure you also appreciate.