A team of divers worked most of March 19 fixing a faulty release valve on the Parker Canyon Lake dam.
Gordon Bleyl, an engineer for the Arizona Game and Fish Department, said the safety valve is rarely used but needs to be operable just in case.
“It’s called a principle outlet and used if you have to drain the lake for emergency purposes,” Bleyl said. “Otherwise we don’t release water out of that.”
During the operation, the divers that Bleyl hired from the Tempe-based company Rubicon also discovered a small “trickle” leak during a video inspection of the pipe that does allow water to come in.
Bleyl said the fix will be very difficult to make and draining the lake is not an option at this point.
“In all honesty I don’t think that leak is big enough to even warrant to take that action,” he said, adding that otherwise the pipe is in “great shape.”
Bleyl estimates that the leak has caused the lake level to decrease annually by about six inches, which he said is a drop in the bucket compared to what is lost through overall evaporation and lack of rainfall.
“We lose more water from one summer month of evaporation then we do all year to that leak,” Bleyl said.
It’s those drought conditions that Bleyl said has caused the most noticeable drop in lake levels.
“If you don’t get a good rain on an entire watershed the lake doesn’t fill up,” he said.
In the meantime, Bleyl said, he has monitoring equipment in place to detect if the leak changes and requires drastic action. Many dams have seeps that are simply monitored.
“It’s not a huge deal,” he said, adding that the minuscule amount of leaked water just ends up going down stream.
Bleyl said the cost to make the valve operational as well as the inspection was approximately $80,000. It was a fair price, he said, considering the potentially hazardous 60-foot-plus depth at which the divers had to work, as well as the time and expense of having safety precautions such as a decompression chamber on hand.