Natural floodplains will be restored to the Bronx River Forest just beyond the Allerton ball fields and French Charley Playground in Norwood, park officials and advocates announced last week. Construction began on July 12 and will take 12 to 18 months to finish. The results will benefit both wildlife and park visitors.

"The Bronx River came a long way since it was an open sewer," said Parks Commissioner Adrian Benepe was at the project’s groundbreaking ceremony last Friday. "Now we need to make it a treasure both for the Bronx and for New York," he said.

The project was initiated by the Department of Parks and Recreation and the Bronx River Alliance, a coalition of local groups advocating for the once-neglected river. Besides restoring floodplains, boardwalks will be built along the same section of the river so park visitors can access the river even when the regular walkways are flooded.

Floodplains, the areas around a river that soak up excessive water, have an important place in the river environment. Rivers often flood during heavy rain or snow thaws. This slows the fast-flowing river and prevents it from excessively eroding nearby land. During the dry seasons, floodplains release the water into the river, maintaining the water level. 

Along the Bronx River, the Bronx River Forest is the only site in the borough that works as a floodplain. It is also one of New York City’s last floodplains. Many former floodplains were replaced over the years by street paving and buildings, or by concrete riverbanks. 

The Bronx River Forest, too, had been affected by urban development. Its bending path was straightened by artificial banks of earth for the construction of the Bronx River Parkway. The Forest no longer absorbed water during flooding seasons, and the fast-moving river eroded the forest.

Erosion led to the problem of heavy sedimentation in the river. Eroded soil and nutritious sediment that floodwater once washed onto the floodplains now collects in the river.

This damaged the Bronx River Forest’s ecology. Fish and other marine life suffered from the sedimentation in their habitat. And without the nutrients from the sediments, native plants suffered and were crowded out by more resilient and non-native plants. 

The most pervasive example is Japanese knotweed, a bamboo-like plant that can grow up to 10 feet tall and thrives both on the riverbanks and in the Forest, said Marit Larson, a Parks Department project manager. "It dominates all other native plants and prevents young trees and seedlings from growing up," she said. "There’s no diversity in the habitat, and that means less diversity in animals because there are less plants for foraging."

She said that the tall knotweed is also a "visual barrier" that makes park goers feel isolated.Knotweed will be eradicated in select areas and replanted with native flora. New fish habitats will also be created.

By removing the artificial banks and allowing the Bronx River to flood naturally, park officials and river advocates hope to improve the river’s water quality. 

"I am really thrilled to see this," said Linda Cox, executive director of the Bronx River Alliance. "This will make the Bronx River better for wildlife and park visitors."

The floodplain project is part of a larger plan to create 11 miles of Greenway paths along the Bronx River, according to Bronx Parks Commissioner Dorothy Lewandowski, who also attended the groundbreaking. The $2.9 million project is funded by the city, the New York State Department of Environmental Conservation, the New York State Department of State and the New York State Attorney General.

Ed. note: For more information on the Bronx River, visit www.bronxriver.org.