NORTH ADAMS - After roughly 60 years protecting the city from high water, concrete flood chute panels carrying the Hoosic River through downtown have started to fail.

Two concrete panels collapsed into the river this past year, one leaving a foundation of MASS MoCA vulnerable to erosion. Another failed over 10 years ago and was replaced.

The Hoosic River Revival coalition has been working for nearly nine years to design a new flood control system that would return most of the riverbed to a natural habitat supporting water fowl and fish, attract recreational use and still protect the city from flood.

"We want to move from eyesore to asset," said Judy Grinnell, volunteer founder and coordinator of the group. "And we need to make sure we keep the flood protections, but it can still be an economic asset to the community."

The project could take more than 20 years and cost $200 million. Officials note the existing flood chutes cost $15 million between 1950 and 1958. In today's dollars, that comes to roughly $150 million. The Hoosic River group intends to fund the work through state, federal and private sources, rather than city tax revenues.

AVOIDING CRISIS

Another challenge is designing a flood control system that would incorporate structures to replace the weight-bearing flood chute panels that support infrastructure like bridges, roads, buildings and parking lots.

The effort seems to be at a tipping point in the effort to make the Hoosic River a community recreational and economic resource: With a preliminary design for a stretch of river just south of downtown, Grinnell is stepping aside as the group prepares to welcome a paid executive director for the first time.

"We've gone from dream to design," Grinnell said. "Now we've got to move it from design to development."

The expectation is that the workload is likely to grow quickly and demand even more expertise and experience in urban hydrological design.

Cindy Delpapa, riverways program manager for the Massachusetts Division of Ecological Research, said the state and federal governments consider the effort a priority project. As such, the DER has been providing technical assistance and funding. She noted that so far, the city has not had to spend any money on the project.

She acknowledged that with panels starting to fail, time is of the essence.

"The concern is that the flood chutes are not going to last forever," Delpapa said. "It's better to plan and replace while we have the luxury of time, rather than wait until it becomes a crisis."

Since 2014, Hoosic River Revival has chosen the south branch of the Hoosic River in the Noel Field area for the Phase One project. It netted $8.7 million in state funding over four years for Phase One work, convinced then-Gov. Deval Patrick to release $500,000 for that design and set 2020 as the goal to complete that first stage, which is estimated to cost $20 million.

DIFFERENT TIME

North Adams Mayor Richard Alcombright said that in the 1950s, the technology of flood control was different — even antiquated, compared to current methods.

"When we look at the river and the flood controls we have now, they would never have done it that way today," he said. "It will still capture the water but in a way that keeps the river in its natural state as much as possible."

But the federal government built the flood control barriers, and they should help replace it, Alcombright said.

"We've got to get the government to help us keep pace with this," he said. "At the end of the day, these panels are going to fail and we need a solution."

Sasaki & Associates and design firm InterFluve came up with the preliminary design for Phase One. The design provides community access to the river banks, ecological improvement in the river, a variety of recreational opportunities, year-round use with easy connections to cultural and historical attractions, renewed wildlife habitats, and hike/bike paths.

Amenities include a river overlook, urban orchard, restrooms, parking, playground, dog park, skate park and splash pad. Joe Wolfe field would remain where it is, but two other ballfields and one soccer field would also be part of the riverside park. One or more pedestrian bridges over the river could be included.

The path of the river would be altered, introducing a more winding path that would tend to slow the speed of the water flowing through the park. The slope of river banks would be more gradual on both sides, offering pedestrians recreational access.

DESIGN FEATURES

According to Hoosic River Revival, the restoration will "develop and enhance stable river corridor habitats, improve water quality, re-establish riverine habitats, and restore in-stream connectivity."

The design is intended to create a waterway that is "largely self-maintaining, reducing overall long-term costs."

Features include:

- Riffles in the center of the low-flow channel add oxygen to the water and support a number of aquatic species.

- The low-flow channel at the center of the river bed allows for fish passage in all seasons.

- Deeper pools interspersed in the habitat offer a refuge for fish during warm weather.

- Wood protruding from banks into the river would help stabilize them and provide habitat for native trout.

- Bioengineered banks would feature dense native grasses, shrubs and trees, rather than concrete, to further stabilize edges of the riverbank.

Similar elements could be used in flood control measures through the rest of the city.

Officials acknowledge that many existing panels would have to remain, or be replaced with something similar.

"There's no way the restoration can replace the entire system with something new," Delpapa said. "Some of the panels that serve to support other improvements will remain because there is no option."

But the actual riverbed would likely be returned to a natural condition.

And wherever possible, the concrete panels would be replaced with environmentally suitable materials and plantings, offering more opportunities for people to interact with the urban landscape.

Recently, Sasaki & Associates was hired to come up with a preliminary design of the branch from north of Eclipse Mill to MASS MoCA.

OTHER EFFORTS

Hoosic River Revival's work coincides with other efforts to develop recreation and tourism. Those include the Berkshire Scenic Railway, the development of the hike/bike trail from both Adams and Williamstown, development of a railroad museum adjacent to the river and the final phase of MASS MoCA's development of Building 6.

Brian Miksic, a member of the volunteer board of Hoosic River Revival and a member of the North Adams Planning Board, sees economic opportunities resulting from the project.

"Around similar projects we've seen property values go up and property tax bills go down," he said.

Miksic said upgrades like this create business opportunities and attract new families to the area. He noted that a 20-year project can be done, pointing to MASS MoCA's more than 20-year evolution.

"If we never start, we'll never finish," he said.

Alcombright also sees economic opportunities in any revival of the Hoosic River.

"It will change the landscape of the city, but it will also provide all kinds of recreational opportunities and economic impacts," he said. "There will be more new visitors and new businesses and that would help build the tax base of the city."

But officials acknowledge the process will be long, difficult, expensive, complicated and in some cases controversial.

"It's going to be a challenge," Grinnell said. "I'll not diminish the difficulty. The board will have to raise this money."

The project would require land acquisition and building demolitions and the widening and possible reconfiguring of the riverbed.

But, as Grinnell asked, "We're going to have to fix this thing anyway, so why don't we do it right and turn it into an asset? We are at a threshold for this project to start to transform the city."

Reach staff writer Scott Stafford at 413-496-6301.