A CT river could solve flooding troubles. But it might cost $50M.

The north branch of Park River — part of an urban forest with some of the oldest trees in the city — should be dredged and shored up as part of a larger plan aimed at easing the flooding that has plagued North End neighborhoods for decades, a new study is expected to recommend.

The project could cost up to $50 million.

The study by the city of Hartford and the Metropolitan District Commission, the regional water and sewer authority, is expected to recommend the dredging so the north branch of the Park River can handle more storm water in the future from neighborhoods in the city’s North End. The dredging and bringing erosion under control also would lessen the chances of the river overflowing its banks.

The report, expected in August, focuses on a 2-mile stretch of the river that courses through the city’s West End, Blue Hills and Asylum Hill neighborhoods.

How the river dredging would be financed is unclear. The scope and a potential timetable has yet to be established. Any project would have to work with the owners of private property along the river.

While the final report is not expected until next month, some details that are likely to be recommended surfaced at a recent meeting of the Greater Hartford Flood Commission .

Far more storm water is expected to flow into the north branch of the Park River after the now-combined sewer and storm water systems in the Blue Hills and Granby Street neighborhoods are separated, according to Scott Jellison, the MDC’s executive director, said.

“There would be enough capacity in the river to accept the storm water that right now doesn’t have the capacity to handle it,” Jellison said.

Hartford Mayor Arunan Arulampalam, who wasn’t at the commission meeting, declined to comment until a final report is issued.

In a statement, a spokesman for Arulampalam said the mayor is committed to tackling with the long-standing flooding issues in the North End.

“While the joint study with the MDC is conducted and recommendations are developed, the city will continue working with the state and local partners to provide relief to residents whose livelihoods are threatened by storm water as a result of decades of disinvestment,”

The river project would preserve the natural woodland environment. That stands in contrast to the south branch of the river that is enclosed in concrete canals, mostly underground, as it flows to the Connecticut River.

The approach was a relief to conservationists. But they still worry about how the dredging project would affect planning for the lands that border the river and to what extent trees might need to be removed.

The river may need to be widened in certain areas.

“There are clearly trees of advanced age there,” Jack N. Hale, chairman of Hartford’s tree advisory commission, said. “Those big trees are the ones that really provide for a lot of the environmental value in the urban forest. And each one that is lost is a major loss.”

Trees and tree canopies in cities are seen as crucial to easing the build-up and storage of heat in urban surfaces and impacting the health of residents.

Hartford’s tree ordinance requires permits for any trees that are taken down.

Mary R. Pelletier, director of the Park River Watershed Revitalization Initiative, said efforts of the watershed group should be fully aligned with the project envisioned should the dredging project move forward.

Pelletier said there is an opportunity to make the north branch of the river a strong asset for Hartford, but that will require planning and funding.

“And making a priority of that,” Pelletier said “Instead of saying, ‘Hartford can’t afford to have nature in their neighborhoods. Hartford has to be the parking lot for commuters.’ “

Overflowing its banks

Flooding already is a problem on the north branch of the Park River. Bank erosion causes trees to topple into the river, forming dams that collect other debris.

In heavy rains, the river can overflow its banks, inundating low-lying areas near the river. The river also can take on a brown color, as it did last week, as accumulated sediment is stirred up.

Mike McGarry, chairman of the flood commission, said he believes more study is necessary – especially during the spring – when water levels historically rise to their highest.

Some dredging may be necessary in certain areas of the river, McGarry said.

“The idea of dredging the whole river and spending $50 million when the river is going to do what it wants to do is very questionable,” McGarry said.

Even with dredging, aggressive maintenance – removal of fallen trees and other debris – would be necessary.

If there is opposition to dredging, Jellison said there is a more costly, $150 million alternative. That would involve a new, 1.6-mile pipe and pumping station that would move the storm water to the south branch of the Park River.

If approved, the dredging would be a part of a larger, far-reaching project. The project includes eliminating back-ups to individual homes and businesses, in addition to separating the main lines that carry sewer and storm water away.

Right now, if there are heavy rains, the combined system overflows into the Park River. Once separated, only storm water would be dumped into the river, with sewage making it way to the treatment plant in the city’s South Meadows.

In addition to Hartford, Windsor and Bloomfield have waterways that flow into the north branch.

Kenneth R. Gosselin can be reached at kgosselin@courant.com .