Martha Rial, Post-Gazette Marijke Hecht pauses while walking along Nine Mile Run in Frick Park where the $7.7 million stream restoration has just been completed. Ms. Hecht is executive director of the Nine Mile Run Watershed Association. Click photo for larger image. Graphic: Aquatic Ecosystem Restoration Project

The first clue that something different is afoot along Nine Mile Run in the southern end of Pittsburgh's Frick Park is the "meanders."

It's a country kind of word, easygoing and lazy sounding, and the creek also now has that slower, country kind of feel as it snakes from pool to riffle to pool, a mile of multiple meanders in a flood plain between South Braddock Avenue and Commercial Street.

It's a more natural course for water, but one rarely found in an urban environment where stream flows are regularly piped and culverted and channeled through concrete in as straight a line as engineering can build.

Nine Mile Run was in just such a straitjacket for a century, channeled along and under the Parkway East, then funneled together with leaking sewer lines through towering mounds of steel mill waste slag on the border of Squirrel Hill and Swisshelm Park to the Monongahela River at Duck Hollow.

Three years ago, the Nine Mile Run Watershed Association and the U.S. Army Corps of Engineers started to break the creek out of those unnatural constraints, and today, city, state and federal officials will celebrate the successful completion of the stream restoration with a dedication ceremony at the Lancaster Avenue entrance to the park.

"This waterway has come so far," Marijke Hecht, executive director of the Nine Mile Run Watershed Association for the past four years, said earlier this week. "A lot of people have worked very hard for a long time and the ceremony [today] is a chance to celebrate that. But there's still a lot of work to be done."

The $7.7 million project restored 2.2 miles of the stream and parts of two tributaries -- Fern Hollow Creek and Falls Ravine Creek, which was "daylighted," or removed from an underground pipe. The city paid $2.7 million, some of it from the Heinz Endowments, to leverage $5 million in matching funds from the U.S. Army Corps of Engineers' aquatic ecosystem restoration program.

It was the first ecosystem restoration project done by the Corps' Pittsburgh District, and required intense collaboration and a steep learning curve, according to Lenna Hawkins, a Corps engineer and branch chief for programs and project management.

"It was complicated because it was an urban stream and we had to deal with four or five municipalities. It is also a nontraditional role for us," Ms. Hawkins said. "This is very different from the kind of concrete-paved stream channel we built around Johnstown. In this case nature will guide you and you've got to listen."

The stream, wetland, riparian landscaping and trail work was finished at the end of June. Designed by Biohabitats of Baltimore, and constructed by Meadville Land Services, from Crawford County, under the direction of the Corps of Engineers, it is the largest urban stream restoration project in the nation and one of the first to utilize new restoration ecology techniques that mimic natural ecosystems.

"We stabilized the system by rerouting the creek and installing riffles and pools. It was a huge construction project and will require constant management," Ms. Hecht said. "This will never be an aquatic system we can just walk away from."

Shielded from motorists on the Parkway East by stands of tall sycamores, the run and its tributaries now twist and turn through wide wetlands where cattails and sedges grow, and meadows planted with tall native grasses and wildflowers. Those areas catch floodwater and recharge the stream in dry, low-flow times.

Willow switches have taken root along some of the stream banks, and oak, sycamore and silver maple saplings are thriving among the grasses and wildflowers despite the grazing pressure of the Frick Park deer herd. "Slash piles" from trees cut during the construction process and standing "snags," of dead trees have been left in place to provide bird and animal habitat.

"It's supposed to be a natural system and there's a messiness to it," Ms. Hecht admits. "That's an issue for some, but those snags and brush piles are critical for habitat. I've seen flickers and red-tailed hawks in them. In 40 years the willows and other trees will shade the creek, which will be important for the fish."

The fish are another clue that things are changing on Nine Mile Run. For the first time in 100 years, three game fish -- smallmouth bass, striped bass and sauger -- have been found in the creek, along with several species of minnows and crayfish. Aquatic insects -- caddis flies and mayflies -- indicative of cleaner water, have also been discovered in a survey conducted this summer.

The creek is cleaner because Wilkinsburg, Swissvale and Edgewood have reduced sanitary sewer overflows and the city has fixed leaking sewer lines and cut down on the frequency of its combined sewer overflows. Still, on Tuesday, after a light rain Monday night, there was a noticeable odor of sewage at the end of a culvert that discharged into the creek near Commercial Street.

"The water quality and quantity improvements are why the fish are coming back," said Dan Sentz, the city's environmental planner and project manager on Nine Mile Run. "Prior to the upgrade there were completely dry sections of streambed and storm surges that washed fish back down into the Mon. Stream bank stabilization has also reduced sedimentation."

But the creek is still inundated by industrial pollution, road salts and lawn chemicals. Also a big, visible problem, Mr. Sentz said, are the "floatables," grocery bags, snack bags, cigarette butts and food wrappers, that are littered on urban streets and then washed into the sewers during storms and deposited along the creek's high water line.

"This is not a rural watershed. We understand that, but we want a healthy stream where people can recreate," Ms. Hecht said.

"One of the big benefits of the restoration is it focuses public attention on the stream, and when it smells of sewage and is strewn with trash, people will notice that and hopefully do something about it. We're working toward being confident enough of the water quality to be able to walk in the streambed or have a toddler splash in it. We're not there yet."

A watershed association Rain Barrel Program to reduce storm water flow into Nine Mile Run by collecting rooftop runoff has distributed 500 barrels and aims to enroll 4,000 houses, 40 percent of the residences in the watershed.

Much other work remains too. Invasive species like Japanese knotweed, a non-native plant, have been persistent problems. A boardwalk over a wetlands area near Commercial Street is under construction by the city, and there are plans for a new parking lot and entrance to the creek, greenway and park trails off South Braddock Avenue.

Ms. Hecht has made it a priority to rebuild the concrete plunge pool on Braddock Avenue to stem erosion that is undercutting the creekside trail. After storms, that outflow, which handles 70 percent of the water in the watershed, resembles a turbulent "class four rapids," she said.

A new pedestrian bridge over the creek in the lower section near the slag piles also is needed to replace an old industrial bridge removed to facilitate water flow. Without the new span, which will cost several hundred thousand dollars, she said, trail bikers and walkers can't access the Monongahela River.

The association is seeking grant and foundation money for those projects.

"The bridge and the plunge pool have to happen in the next two to three years for this stream restoration project to have meaning," Ms. Hecht said. "As for the water improvements, I don't know how long it will take for a toddler to safely splash in the creek, but we need to put some time limits on it to make sure we can and will get there."