The Metropolitan Water District of Southern California recently gave its lifeline to the Colorado River a flu shot.
For the first time since water from the east began flowing into Southern California 61 years ago (the first water was released in 1941), Metropolitan shut down and drained its Colorado River Aqueduct in October for repairs and upgrades. Keeping the 242 miles of pipes, tunnels, open canals and siphons in top working order is a way for the district to manage its risk and keep larger problems from developing, officials said.
Call it a little preventative medicine for Metropolitan's aging workhorse.
"We've done a good job over the life of the aqueduct as far as maintaining it, but there comes a point in time, to continue to ensure the reliability (of our water supply), it has to go beyond just maintenance," said Eddie Rigdon, assistant manager for Metropolitan's Water Systems Operation group. "The aqueduct has been so reliable and we have been so dependent on it we haven't had the luxury to shut it down and do what we are doing now."
From October 1-15, Metropolitan stopped pumping water from the river, allowing crews access to previously full reservoirs at Iron and Eagle pumping plants, head gate structures, sand traps and tunnel sections. Work included sandblasting and coating nine-square foot slide gates used for flow control, joint replacement on 10-foot diameter piping, relining two 100 acre-foot reservoirs, removing and replacing canal lining, replacing 300 sand trap trash racks, replacing high voltage protection relays and surge protectors and inspecting miles of tunnels.
Rigdon compared the work on the aqueduct to keeping an aging car running.
"Much like a car, you can maintain and maintain and maintain, but ultimately there's a time you need to replace things because of age," Ridgon said. "The CRA has provided us the reliability we've needed, but to further ensure that, we needed to go a step further."
That extra step means that when the $16 million rehabilitation project is completed after a second shutdown scheduled for next year, about 225,000 square feet of canal lining will have been replaced and 20 slide gates will be refurbished. Two reservoirs will have been relined, protective relays and surge protectors will have been replaced at all five plants and 300 sand trap grates will have been replaced, as well as a complete inspection of the aqueduct and its supporting structures that will allow Metropolitan to proactively respond to future repairs. Planning for the rehabilitation project has been in the works for nearly three years. The system normally carries 1.25 million acre-feet of water annually, but the aqueduct can hold up to 1.3 million acre-feet. To ensure Metropolitan got its full complement of Colorado River water this year, pumps ran at capacity both before and after the shutdown, to make up for the weeks when no water would be moving.
"Working in very isolated areas made logistics a challenge, but we were able to plan far enough in advance to be ready," said Gary Suiter, project manager for the shutdown.
The warm, clear, dry desert weather was perfect for the work and the only injuries were two scorpion stings and a pinched finger. He compared the magnitude of the project to the original construction of the aqueduct in 1939. This time, there were about 650 people—a combination of Metropolitan employees and contractors—working day and night during the shutdown. Metropolitan workers were housed in dorms at Gene, Iron Mountain and Eagle Mountain, and hotels in Parker and Indio. Metropolitan bought 17,000 pounds of food to feed its employees. That translates to 697 breakfasts, 1,400 lunches and 767 dinners.
Suiter said the sight of hundreds of people working in desert areas that are normally sparsely populated was inspiring.
"The first night, coming back into Hinds (Pumping Plant) we crested the ridge and, out of nowhere, saw this city of lights from the work crews along the canal," he said. "It was spectacular to see."
One of the factors that afforded Metropolitan the opportunity to work on the aqueduct was Diamond Valley Lake, the 800,000 acre-foot reservoir brought online in 2000. With the lake 90 percent full, Metropolitan had enough storage to handle a 15-day outage of Colorado River imports and still meet the water demands of its 26 member agencies.
"Diamond Valley Lake was the key," Rigdon said. "We did this during the driest year in Southern California's recorded history and we were able to do it during very high demand periods.
"In past years, we wouldn't have considered it," he said. "We are confident we can go another 50-60 years with the same confidence level we experienced in the early years."
Click here to view a
"Straight from the Tap" video
of the CRA shutdown.
