NEWS ANALYSIS : Tapping Into Water Usage Data Not Cut and Dried

Mayor Tom Bradley has a tough decision to make. He has asked Angelenos to voluntarily cut their water usage by 10% this month, or face mandatory water rationing.

But what makes the mayor’s decision on rationing particularly difficult is that the city’s Department of Water and Power has no way to immediately measure how much water residents save.

And with the crucial water consumption report to the mayor due in two weeks, officials are still at odds about what to use as a benchmark for the city’s water conservation efforts.

The mayor’s staff and DWP are--literally--years apart in their approaches, which could make a dramatic difference in the lifestyles of Los Angeles residents this summer and beyond.

Under one interpretation by the mayor’s staff, the 10% cutback sought by Bradley would be in addition to an estimated 4% to 8% reduction already achieved during the last several years. That means Angelenos are being asked to cut usage by 14% to 18% of their historical, pre-drought consumption.

DWP officials, however, say that water savings accomplished since 1988, when the city launched conservation programs, should be included when calculating the 10%. Under that formula, residents only need to curb their water use by an additional 2% to 6% this month.

The interpretation by the mayor’s staff is unrealistic, say DWP officials. “To expect that within a day or two people would immediately conserve that much is unreasonable,” said Henry Venegas, assistant manager of engineering design at DWP.

In preparing its report for the mayor, DWP will measure use in the fiscal years 1987-1988 through 1989-1990, “and factor in increases in population . . . and, as best we can, the effects of weather and temperature (on water consumption),” Venegas said.

But Mark Fabiani, chief of staff to Bradley, said, “We’re asking people to conserve 10% of what they are using today.” Fabiani said the best way to measure that response would be to compare April consumption to March.

That sounds simple enough. But numbers on usage take a while to compile. The latest water sales figures available from the DWP are for February. DWP officials said that March numbers will not be available until sometime next month and April figures will not be read off the meters and compiled until mid-June--about six weeks after the mayor expects an answer.

Estimating conservation is further complicated by disagreement among experts over the need to calculate the effects of weather, existing conservation efforts and population growth.

Even the raw figures can be confusing, and consumption has fluctuated during the last three dry years. While consumption fell 3% from 1987 to 1988, it went up 2.2% from 1988 to 1989.

Water use climbed 4.2% during the first eight months of the current fiscal year, when compared to the same period a year ago.

Venegas said he could not explain the ups and downs of water use in recent years. But he speculated that some growth is due to population increases and dry weather that encourages more outdoor watering. Some moderation in usage is attributable to conservation, but just how much DWP is unable to say.

In 1988, the city adopted phase one of an emergency water conservation ordinance that bans wasteful water practices such as hosing down driveways and sidewalks. Now that the state is entering the fourth straight year of dry conditions, Southern California water officials are forecasting a water shortage of as much as 12%. Bradley said he hopes that voluntary efforts will save enough water to avert rationing this summer.

DWP has come under fire for not preparing properly for the city’s future water demands either through conservation or new supplies.

In a detailed management study released this week, auditors said that DWP had not adopted procedures or acquired any monitoring devices to evaluate conservation in recent years.

Earlier efforts by DWP to build forecasting models of water use and demand came up short.

A consultant hired by DWP in 1987 developed a system to predict water demand but, the management audit report found, there were “questions about accuracy . . . and the consultant has not responded with corrections or modifications.”

Other water use projections by DWP also were flawed. The management audit found that the department’s last effort to forecast demand was in 1985. Usage levels predicted for 1990 were surpassed by 1988.

The latest DWP estimate on conservation comes from studies of sewer flows that show the city has cut water usage by up to 8% since 1988.

James Wickser, assistant general manager for water systems, said sewer flows have been down about 2% in each of the last two years, even though the flow was expected to be up about 2% because of population increases. So Wickser added the two figures together and reasoned that the drop must be due to reduced per capita consumption.

But the sewer method of calculating conservation is not universally accepted. In the management audit released this week, auditors said: “No process or methods for measuring (conservation) exist . . . other than rough estimates of sewer flows and a count of shower heads.”

Moreover, DWP acknowledges, upwards of one-half of all water is used outside the home and never enters the Los Angeles sewer system.