DONALD C. TILLMAN WATER RECLAMATION PLANT | The LA River used to go dry as dirt; today it flows year-round, at least a little, because so much of its water comes from unnatural sources. Twenty-six million gallons of recycled water, more than a quarter of the river's dry-season flow, enter from this facility in Van Nuys. A lovely 6.5-acre Japanese garden onsite puts a tranquil spin on sewage.

POLLYWOG PARK | Technically part of Griffith Park, Pollywog Park was marooned on the north side of the river—and then on the far side of the 134 freeway—when engineers changed the river's course during channelization. The plan calls for transforming a drainage ditch along the freeway into a tributary with native vegetation and a wildlife area.

VERDUGO WASH | At the north end of Glendale, just after the river takes its turn south, this concrete-lined section will become a wide, soft-bottomed oasis. On the eastern banks, a wildlife refuge and a backwater area will replace a rim of industrial sites.

LA KRETZ CROSSING | The first major project of the LA River Revitalization Corporation—an entrepreneurial nonprofit the city set up—is a footbridge connecting North Atwater Park with Griffith Park and the river bikeway. Construction on a $10 million, 300-foot-long cable-stayed bridge should start later this year.

TAYLOR YARD | This former rail yard on 247 acres along 2 miles of riverfront has long been a battleground between developers and activists. In 2007 the state revamped 40 acres into a park; the city is negotiating for another 40. The Army Corps will widen the river here, replacing the concrete walls with natural, sloping banks.

ARROYO SECO | The river's confluence with the Arroyo Seco is one of the most blighted sections, a wasteland of concrete and trash. A soft-bottomed wetland will replace the now garbage-choked ditch, and designers have proposed a bike path for the terraces.

CORNFIELDS | Corn used to fall off railcars and sprout in the dirt here. In an early victory for river advocates, the state purchased some of the land 14 years ago and created the LA State Historic Park. Plans call for restoring a former stream and marshland, with railroad tracks on a trestle above. Lauren Bon, a local artist and philanthropist, is in talks to build a 72-foot-diameter, $10 million steel water wheel, an homage to one that stood here in the 1850s and was used for irrigation.

SIXTH STREET VIADUCT | This historic bridge-cum-homeless encampment downtown is a pile of disintegrating concrete just waiting to collapse in an earthquake. Soon it will be replaced by a federally funded $400 million pedestrian and car bridge with access down to the river and new gardens. Artist Glenn Kaino has a commission for an “acoustic bridge,” where people on opposite sides could talk to each other using normal voices.

GREENWAY 2020 | A centerpiece of river redevelopment, this 51-mile bike path would follow the entire river. Mayor Eric Garcetti's new strategic transportation plan, released in late 2014, included a goal of building the bikeway by 2020. “We are talking about connecting LA in a totally new way,” says Omar Brownson, executive director of the LA River Revitalization Corporation.