The Buffalo Bayou is everything Houston city planners once despised: The small river that winds through glassy downtown hi-rises has gentle curves, a slow, meandering current and native grasses teeming with birds and insects.
More than half a century ago, millions were spent to tame the flood-prone channel, turning it into a straight sluice to carry excess water to the Gulf of Mexico. The project reduced flooding, but it stripped the waterway of its natural beauty and created environmental problems.
Now, Houston and other cities are spending millions again. This time to restore natural bends, vegetation and even mild rapids to urban waterways. Rather than corral and conquer nature, today's planners want some wildness to the water both to improve the environment and to attract young, nature-loving city dwellers.
"It's not about getting to the point where you can build multi-billion, hi-rise condos. It's about giving communities access to the water and maintaining it," said Mike Shapiro, an administrator for the Environmental Protection Agency's Office of Water.
Like many city rivers, Houston's bayous were once a dumping ground for trash and raw sewage. The water smelled so bad that an annual canoe race was dubbed the "reeking regatta," said Kevin Shanley, a landscape architect who specializes in urban river projects, including the Buffalo Bayou.
Shopping carts, refrigerators and other household trash floated down waterways. The Army Corps of Engineers invested millions to uncurl rivers and cement them into place.
Today, the Buffalo Bayou and a few others are becoming more reminiscent of the swampy wetlands they once were: Native plants line the streams, trails run along more natural river bends, and native grasses are taking root.
Downtown-revitalization projects have been trendy for decades, but these river projects go beyond sprucing up a business district. They undo decades-old, multimillion-dollar flood prevention projects.
When first proposed, those projects offered protection from unpredictable weather. But they also sped up erosion, damaged water quality and made water recreation scarce, if not impossible.
Now the "restoration of urban rivers is becoming a real focal point," said Guy Hagstette, a consultant with the Buffalo Bayou Partnership.
In Grand Rapids, Michigan, planners want to remove several dams and install boulders to restore some downtown rapids, the city's namesake. A decades-long master plan for Los Angeles aims to bring back natural elements of a mostly concrete-lined river.
Philadelphia and other Delaware River towns are restoring habitats and promoting residential access alongside flood-control and cleanup.
City planners understand that by allowing a river to flow naturally, erosion can be contained, water will be cleaner and clearer, and river banks will be stronger, Shanley said. To achieve that, a river must bend and be surrounded by native vegetation. And the plants help keep water clean.
Planners also hope the projects will provide young urban dwellers -- seen as the foundation of a vital economy -- with the parks they crave.
American cities are increasingly competing "not just with New York and Chicago, but with Chattanooga" for young people, "and these are the kinds of amenities that people want," said Anne Olson, president of the Buffalo Bayou Partnership, the nonprofit overseeing Houston's project.
"Quality of life," she said, "has risen to the top of Houston's agenda politically and economically."
Houston embarked in 2012 on the ambitious $58 million Buffalo Bayou park project -- nearly all of which is privately funded -- and is investing another $100 million to create pathways to connect 150 miles of bayous.
The public embraced the improvements, approving a $250 million bond issue during the Great Recession to connect the rivers with hike-and-bike trails.
The projects have attracted attention. Baton Rouge officials came to see a promenade along Buffalo Bayou. EPA Administrator Gina McCarthy toured the park, marveling at wetland plants that serve as a natural water filter.
It was McCarthy's predecessor, Lisa Jackson, who identified the national river renewal trend in 2009, and instructed the agency to help, Shapiro said.
The Urban Waters Federal Partnership was born in 2011 to respond to complaints that federal agencies were un-coordinated, and they were often unaware they were working on separate but related projects -- sometimes just blocks from one another. By last year, more than a dozen communities had been included, and 13 federal agencies were collaborating. The EPA has awarded about $5 million in small grants.
In the New York City suburb of Yonkers, the first step in restoring some waterways is uncovering channels buried long ago as part of complex sewer systems. Nearby communities along the Bronx and Harlem river watersheds are transforming contaminated channels into venues for canoeing, hiking and biking.
"Water-quality restoration, especially in urban areas, does not happen overnight and often takes decades," Shapiro said. "In some places, restoring an urban waterway literally means ... finding the waterway again."