Perhaps nothing speaks more to the challenge of sustainably managing infrastructure systems than attempting to measure their performance. It's a daunting task, at best, to merely inventory a city's systems -- water, energy, transportation and water, for example -- much less to describe and catalogue their many functions and interdependencies. Adding verification that the systems are sustainably managed would seem to be virtually impossible.

Some cities, however, are paving new ground toward making the impossible possible. While many communities have set sustainability goals, plans and programs, a lesser number are actively communicating their progress. A few cities have significantly raised the bar by defining performance statistics, setting timelines and publishing their results through online performance dashboards. These cities include Kansas City, Salt Lake City and, most recently, Los Angeles, whose Sustainable City pLAn dashboard debuted last month.

Los Angeles' sustainability plan is described as both a "roadmap to achieve back to basics short-term results" as well as a set of broader, long-term goals to strengthen and transform the city decades into the future -- "actions we must take in the coming months and years to secure a future for L.A. that is environmentally healthy, economically prosperous and equitable in opportunity for us all," as Mayor Eric Garcetti put it.

Key to that, Garcetti said, is making the data on how well pLAn is doing to achieve those goals available to everyone. "This data is not our data, it is the public's data," the mayor said, "and the more tools we give to people to look at data, to track important measures, the more power that they will have to control the direction of their city government."

That's where the new dashboard comes in. Target dates, graphed progress data and current statuses are easily viewed for each of the plan's goals. And those goals are certainly ambitious ones, including: by 2050, reduce greenhouse gas emissions by 80 percent below 1990 levels; by 2035, reduce energy use in all buildings by 30 percent; by 2025, increase transportation's walk, bike and transit share to 35 percent of all trips, have zero smog days, increase the landfill diversion rate to 90 percent and reduce the annual number of childhood asthma-related emergency room visits in the city's areas with the worst air pollution to 14 children per 1,000.

It's illuminating to drill down into a single parameter, such as water, given that California is entering its fourth straight year of severe drought. L.A.'s water conservation targets include reducing average per-capita potable water use by 20 percent by 2017, reducing purchases of imported water by 50 percent by 2025, and sourcing 50 percent of water locally by 2035.

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That latter goal gets at the challenges ahead for the city. Major efforts will be needed to provide more locally sourced water, including a transformation of how stormwater is captured and cleaned throughout the region's water basins. This may include, for example, altering sections of the iconic concrete-lined channels of the Los Angeles River, so often used as a Hollywood action movie setting. A successful transformation of the river has the potential to make it more enjoyable for residents and friendly to wildlife, reduce water imports, and create cleaner beaches.

It wasn't simple, of course, to come up with a plan to set the city on such an ambitious course. As Matt Petersen, the city's chief sustainability officer, noted, it took not only leadership from the mayor but also "engagement of department heads, the city council, nonprofits, community groups and others." In a city that expects to have an additional half-million people in 20 years, "we wanted to connect the dots across these subjects -- environment, economy and equity -- to show how they can all work together toward common goals," Petersen says.

The ongoing implementation of the plan's projects will be not unlike the commissioning process for a ship to ensure seaworthiness. Refinements and adjustments will be expected. The sustainability plan is "a living document," said Petersen. "We challenged ourselves to get everyone to own the plan by including them in the process of developing it and by helping them to adopt and use it."

L.A.'s progress will be well worth watching. But a commitment to open data and a fostering of interactions across divergent disciplines are powerful silo-busting actions.