Tuesday, December 23, 2003
DALLAS -- When the Dallas City Council voted Dec. 15 to test a new way of storing water underground, it also put on hold a less flashy project -- upgrading the line that carries water from Rickreall Creek to the City's water treatment plant.
The underground storage method, called aquifer storage and recovery, became a priority for Dallas officials this year. They discovered it could give them another decade's worth of water while they look for a longer-term supply.
Finding out whether the project will work, however, will cost $600,000 in engineering and construction. To fund the test site, councilors pulled money from the water intake line improvement -- budgeted for $300,000 this fiscal year.
Replacing the line would cost $510,000 over two years, said Public Works Director Fred Braun. Now, it will likely take two more years before that project starts.
Dallas residents get their water from below Mercer Reservoir on Rickreall Creek. Water is pumped through an intake line there to the City's water treatment plant just west of town.
When Dallas first developed its water system, that line was made of wood. In the 1950s, the wood line was replaced with one made of steel.
"It was the best product we had in the '50s," explained City Manager Roger Jordan.
Over the years, plastics have replaced steel as the preferred material for water lines. Plastic is stronger, more flexible and doesn't corrode like steel, Braun said.
In 1997, Dallas replaced the first part of its intake line with a type of plastic. The old 16-inch steel line was also widened to 22 inches.
The rest of the line -- the part connecting to the treatment plant -- remains 16-inch steel.
Replacing the first part made sense with the limited money available at the time, Jordan said. The section connected to the pump has the greatest water pressure and was therefore more critical to replace.
The section connecting to the treatment plant hasn't broken, Jordan said, but needs to be replaced because of its age. "The current line is working," he said. "It's not being replaced because of failure; it's just a matter of timing."
City officials identified the line extension project since 1997 on the City's capital improvement list and a five-year goal.
While Jordan said that project can wait, delaying the aquifer project would prove costly. Under the current schedule, Dallas could be charging an underground aquifer by early 2006.
Without that option, officials will have less time to find another way to supply water to a growing population. Current options, including building a new reservoir or piping water in from Adair Village, would take years to develop.
"The [aquifer storage and recovery] project is so important to do the demonstration within the time period," Jordan said, "rather than pursuing an extension to the intake line."