LADWP’s water main leak rate is less than half the national industry average, and leaks have decreased by 37 percent over the past seven years thanks to a proactive plan to replace older and more vulnerable pipes.
But there’s no denying that the water infrastructure is getting older. “We need to ramp up replacement of pipes and other infrastructure to minimize disruptions for our customers and save water,” said Marty Adams, Senior Assistant General Manager - Water System.
LADWP maintains 7,200 miles of pipe, including 6,700 miles of mains and 500 miles of trunk lines. About 280 miles of pipe are already over 100 years old. Without replacements, another 637 miles of pipe will turn 100 years old within the next decade. By 2030, nearly 2,000 miles—27 percent—will surpass 100 years old.
The economic benefits of replacing a pipe before it breaks are clear. A sudden pipe break costs about three times more to fix than proactively repairing or replacing a section of mainline. The rupture of a larger pipe or trunk line running under a major thoroughfare such as Sunset Boulevard or Coldwater Canyon is rare, but the costs are even higher.
Beyond the financial costs of repair and property damage, there are related social and economic costs such as possible risks to people’s health and safety, the disruption of traffic, and the impact on other city services such as the Bureau of Street Services and the Department of Transportation, said Steve Cole, Manager of Water Distribution Engineering.
“The true cost is a triple budget impact—the actual costs, the social and economic impacts, and environmental impacts,” Cole said. “It’s just very disruptive for people and society in general.”
LADWP used an asset management program to develop the Water Infrastructure Plan in 2014, which sets annual and long-term goals for repairing and replacing major infrastructure components. The plan outlines comprehensive improvements, and upgrades and replacements of major infrastructure components such aging pipes, meters, trunk lines and valves. It also looks at improvements to in-city reservoirs and the Los Angeles Aqueduct system.
With 6,730 miles of mainline citywide serving customers, a major focus of the plan is to ramp up the replacement rate of pipes. The fiscal year 2015-16 goal is to replace 28 miles of mainlines. Under the investment plan, LADWP will ramp up the replacement level to 57 miles each year, giving highest priority to 435 miles identified as having a high risk of failure. The plan uses a letter grading system to identify the condition of mainlines based on leak history, soil conditions, age of pipe, and risk of service interruptions. Pipe replacements are prioritized in coordination with the city’s Bureau of Street Services to minimize disruption to traffic.
Because trunk line replacements are multi-year, multi- million-dollar projects, the infrastructure plan focuses on testing and restoring weak sections of trunk lines rather than replacing an entire trunkline, except for instances where a bypass or replacement is required for a water quality project. For example, LADWP is currently installing a new 7,690-foot section of City Trunk Line South (Unit 5) to bypass an older section of this major north-south water artery that runs under Coldwater Canyon Avenue. The project was in the planning stages before the line ruptured under Coldwater Canyon over Labor Day weekend in 2009.
“Even though the trunk line’s history and inspections showed it needed replacing, you just can’t predict when a pipe will fail,” Cole said. “This one happened before we could get to it.”
The trunk line program objectives are to replace, test, repair and preserve sound portions of 40 miles of moderate-to-high risk pipe (D grade) in 10 years; and to replace the lowest grade trunk lines or remove from service to reduce risk of failure and damage.
Replacing large valves (16-inch diameter and larger) is based on operational needs, system shutdowns, demand and reliability. The plan calls for replacing five valves annually. LADWP has surpassed this goal by replacing eight valves annually in the past seven years.
LADWP maintains 94 pump stations that bring water to customers or storage tanks at elevations higher than most of the city. To prevent service disruptions, the plan calls for the replacement of 14 pumps and motors that are near or have exceeded their useful life.
Pressure Regulator and Relief Stations
The Water System has 229 regulator stations and 98 relief stations that control water pressure by adjusting for changes in flow to accommodate customer peak usage. LADWP has identified four to six station retrofits per year through 2022.
System-wide, there are 2,973 large meters (3- inch and larger) and 698,252 small meters (2-inch and less). The Water Infrastructure Plan goals are to replace 25,000 small meters per year; all old meters are replaced with new ones that have remote-reading capability. Currently, LADWP is in the 10th year of a 30-year replacement cycle.
The Los Angeles Aqueduct, which turned 102 years old on November 13, 2015, is the primary water conveyance system owned and operated by LADWP. _ e Aqueduct features 300 miles of tunnels, open channels, covered channels, and sag pipes that convey water from the Eastern Sierra and Owens Valley to Los Angeles. Goals for refurbishing the Aqueduct include relining seven miles of cracked concrete channel within three years.
Investing more funds in replacing and repairing aging water infrastructure is one of the biggest factors driving LADWP’s 2016-2020 Rate Request. Other investment priorities include: expanding the city’s local water supply to protect against future drought conditions; incentivizing conservation; power system infrastructure improvements, continuing to transform the power supply to meet mandates and create a clean energy future for Los Angeles; and improving the customer experience with LADWP—all while keeping rates competitive with those of neighboring utilities.
About 85 percent of all new water revenues will be invested in replacing and repairing critical pipes, pumps, valves and other waterworks in Los Angeles. LADWP expects to invest $2.7 billion during the next five years to upgrade water system infrastructure reliability.
Along with investing in infrastructure, the proposed water rate changes will help protect against drought conditions. New revenues will support local water supply programs already underway to accelerate groundwater cleanup of the San Fernando Valley aquifer, improve stormwater capture, and expand recycled water for irrigation and industrial uses, as well as build an advance treatment facility to replenish groundwater. The water rate proposal also incentivizes conservation by changing the existing tiered price structure from two tiers to four for single-family residential customers.