Jordan Aqueduct Pigged

Successful cleaning operation increases much needed flow capacity.

LeRoy W. Hooton, Jr.

April 6, 2001

Pipe construction necessary to clean the Jordan Aqueduct. Photo courtesy of the Jordan Valley Water Conservancy District.

Jordan Valley Water Conservancy District (JVWCD) General Manager David Ovard calls it “an unqualified success.”  On February 7 and 8 JVWCD cleaned Reach 2 of the Jordan Aqueduct (JA) to restore a 12-mile segment of the 78-inch diameter pipeline to its original flow capacity. Built in 1975, the aqueduct is a major conveyance pipeline supplying drinking water to western Salt Lake County including Salt Lake City. Supplied by water treated at the Jordan Valley Water Treatment Plant (JVWTP) located in Bluffdale, Utah, the treatment plant and aqueduct were built as part of the Central Utah Project.

JVWCD operates and maintains the aqueduct under an agreement with the Metropolitan Water District of Salt Lake & Sandy (MWDSLS) and the Central Utah Water Conservancy District.   The aqueduct capacity is owned outright by JVWCD and MWDSLS, 71 percent and 29 percent respectively.  JA Reach 2 is located between the JVWTP and the 100-million-gallon terminal reservoir located at 5820 South 3800 West Taylorsville. The remaining reach of the aqueduct continues northward to Salt Lake City's corporate boundary at 2100 South 3800 West. 

Over the years the interior walls of the aqueduct became coated with a thin layer of sediment, reducing the flow characteristics of the pipeline. Engineers estimated that as much as 20 million gallons per day of flow capacity was lost due to the coating.  The cleaning process called “pigging” scours the interior of the pipe removing the layer of sediment. This is accomplished by running a cylindrical foam device covered with bristle-imbedded urethane through the pipe.  The device is called a “pig.”  How it became known as a pig is not clear, but it certainly raises one’s curiosity. Water flow behind the pig forces it through the aqueduct.

Preparing for the pigging operation took much longer than the actual two day cleaning process.  Constructing the launching and retrieval facilities took months to complete at a cost of $1,690,000.  The launching facility was located at the JVWTP and the retrieval site at the terminal reservoir.  Flowmore Services of Houston, Texas manufactured the pigs at a cost of $76,683. Carollo Engineers and Bowen & Collins Associates provided the project engineering services.   

Ovard’s obvious satisfaction with the cleaning project means a higher flow capacity to meet the growing water supply needs within the county. Test results after the pigging operation showed that the aqueduct flow capacity increased 22.5 percent from 129 million gallons per day to 158 -- an increase of 29 million gallons per day -- exceeding the estimated 20 million gallons a day expected.

The pig exiting the Jordan Aqueduct with wastewater containing the scoured sediments flushed from the pipe. Photo courtesy of the Jordan Valley Water Conservancy District.

"We're more than pleased with the results," says public utilities deputy director Jeff Niermeyer.  Salt Lake City's ability to deliver water to its growing west side and downtown area increased to 45.5 million gallons per day. "The additional 7.5 million gallons per day is extremely important in meeting the water supply needs of this yet to be fully developed area of the city, including the International Airport," exclaims Niermeyer. The remaining 21.5 million gallons per day goes to the JVWCD to service its customer agencies within Salt Lake County.

The cleaning project was carried out without a hitch.  The wastewater generated by the cleaning operation was captured in an overflow basin of the terminal reservoir and disposed of.  At no time was the drinking water supply at risk of being contaminated by the cleaning operation. At no time was there a contamination risk to the drinking water supply during the cleaning operation.

Properly maintaining the major aqueducts bringing water from Deer Creek and Jordanelle Reservoirs is an important part of providing water to Salt Lake County residents. MWDSLS has cleaned the Salt Lake Aqueduct, located on the eastside of Salt Lake County, twice in recent years. As the demand for more water continues to increase, keeping the aqueducts clean and capable of delivering maximum flows is a prudent investment.