To prevent more breaks this summer in Los Angeles' aging water pipes, the City Council will consider changing the city's water rationing rules today.
Under the proposed amendment to the city's Emergency Water Conservation ordinance, residents at odd-numbered addresses would be able to activate their sprinklers on Mondays and Thursdays, while residents at even-numbered addresses could irrigate on Tuesdays and Fridays.
Those whose addresses end in 1/2 or any fraction would conform to the permitted uses for the last whole number in the address.
If the Department of Water and Power eventually decides to ease the restrictions so residents can water three days a week, then odd-numbered addresses would add Saturdays and even-numbered addresses would add Sundays.
But if the restrictions are tightened further, odd-numbered addresses would irrigate only on Mondays, and even-numbered addresses on Tuesdays.
The Board of Water and Power voted in May to recommend changing the rationing schedule after an independent study found that limiting the use of sprinklers to Mondays and Thursdays was a major factor in the 101 water pipe breaks reported from July through September last year – double the usual number for that time period.
A team of experts led by Jean-Pierre Bardet, chairman of USC's Department of Civil and Environmental Engineering, concluded the rationing schedule created drastic changes in water pressure that put stress on corroded cast-iron pipes and caused them to break, leading to severe flooding in several areas of the city.
One leak even created a massive sinkhole that nearly swallowed a fire truck.
Bardet had warned that unless the rationing schedule is changed soon, there would be another rash of pipeline breaks this summer, when water usage is expected to be higher.
"These weak links [in the pipes] keep appearing, and they are here now, and they are ready to break and create another rash in the summer if we don't prevent the [pressure] fluctuations," he told the board in May.
DWP officials were skeptical of Bardet's conclusions at first, saying, "The model presented is simplistic as noted by the author. The explanation provided is certainly possible or contributory, but is not tested to the level of definitive or conclusive."
Later, however, the senior assistant general manager for DWP's water system, James McDaniel, agreed that changing the rationing schedule "would reduce the magnitude of pressure fluctuations throughout the DWP water distribution system while still providing the necessary water conservation levels."