Besides inheriting the current policy that seeks to end L.A.'s use of coal power by 2025, the winner of Tuesday's mayoral election will face a host of environmental challenges, including the need to increase the local supply of water, maintain momentum on mass transit projects, and fight pollution in toxic hotspots such as Boyle Heights.

Outgoing Mayor Antonio Villaraigosa made perhaps his biggest mark on the environment by aggressively working to end the Department of Water and Power's reliance on coal power. The big challenge at the DWP for L.A.’s next mayor is water, says former agency General Manager David Nahai.

“The unfinished business is developing local water resources,” he says. That means achieving and even accelerating the DWP’s existing goal, to obtain 37 percent of its water locally by the year 2035.

L.A. gets just about 10 percent of its water locally right now. To more than triple that, the city will have to find ways to store water during dry years, and treat contaminated groundwater for wider use -- and, of course, find money to pay for those big initiatives.

Nahai says that means the next mayor may need to make the case for higher water rates.

“This isn’t just an environmental luxury. It’s an economic necessity,” he says. “Because the cost of that imported water is going to rise, climate change will take its toll on the snowpack on which we have become dependent, and the problems of the Sacramento delta are not going to resolve on their own.” Without a statewide water bond, “someone’s going to have to pay to deal with those issues.”

Mayor Villaraigosa also tried to reduce air pollution – and traffic – by speeding up various mass transit projects. They’re funded by Measure R, the half cent countywide sales tax.

Denny Zane, with the pro-transit group MoveLA, says that work will continue, and should be a priority of the next mayor. “Measure R, alone, is going to be a $36 billion program over the next 30 years,” he points out. “Now we want to try to accelerate that and get it done over the next decade. That’s really a big responsibility. So the next mayor is going to have a significant role.”

Zane says Villaraigosa showed how a mayor can use his bully pulpit to advocate for Measure R-funded projects. He credits the outgoing mayor for recognizing a climate in which L.A. voters strongly support transit initiatives, and nurturing it. Villaraigosa created "a new mojo in L.A.” for transit, he says.

Zane hopes that the next mayor continues Villaraigosa’s high-profile advocacy, such as lobbying Congress to complete the America Fast Forward program. That would enable cities around the country to speed up transit projects.

Zane says he’d like to see an expansion of Metro’s Crenshaw line, which he says would cut pollution and be “an extraordinary investment in that community. How much more if it would go all the way up to Wilshire and thereby create for the Wilshire Corridor direct rail access to LAX?”

Both Eric Garcetti Growing L.A.’s economy while protecting the environment is a perennial ambition for any mayor. In communities dealing with various pollution problems, that kind of talk runs into a lot of skepticism. Leonardo Vilchis is with the community group Union de Vecinos in Boyle Heights. He says his neighborhood has earned its reputation as a toxic hot spot – with several schools and old folks’ homes close to freeways’ thick air pollution.

The city should work more closely with regulators to improve air monitoring, he says – and limit the number of polluting businesses that can open in the community – such as the auto body shops, window tinters, and paint shops that line Boyle Heights’ major streets.

“All the machines, the grinding, the oil and all this,” he says, walking past a transmission repair shop, “and the body shop is the same kind of situation, the grinding, the oil, the hammering, the painting.”

Vilchis says businesses here don’t always dispose of waste oil and chemicals properly, leaving them to flow from gutters into city storm drains. “If these small businesses, are not trained, do not have the resources to dispose of that stuff, that goes into the sea,” he says. “So we need to be very aware that the city needs to address these kind of problems because it’s going to affect everybody.”

Two years ago, L.A. launched a program promising environmental relief for Boyle Heights and other toxic hotspots. Clean Up Green Up was supposed to reduce and prevent pollution through a variety of steps, such as incentives for cleaner businesses. Very little of that has happened.

Vilchis says the next mayor should reignite the project by directing city departments to work together on these goals. “The new mayor could immediately put this stuff in the budget and start addressing these issues and then negotiate with the council,” he says. “And if you have this kind of leadership, things will move faster, and the community will hopefully start feeling the impacts of these kind of changes in policy.”

Vilchis acknowledges that money is tight. But he hopes the next mayor of Los Angeles will show the leadership needed to confront pollution in Boyle Heights and communities like it.