Tibbetts Brook

There it proceeds into city sewers, draining into either the northern end of the Harlem River or the Wards Island Water Pollution Control Plant.

The tunnel primarily drains into the Wards Island Water Pollution Control Plant where city sewage is treated.

During rainy conditions the sewer overflows into the north end of the Harlem River, via a drain pipe at about West 192nd Street (Heath Avenue).

At approximately West 230th Street, just north of the current site of John F. Kennedy High School, the brook drained into Spuyten Duyvil Creek, which at the time separated the Bronx from Marble Hill, Manhattan.

[1][3][18][19][20] Until the 1700s, Tibbets Brook split into two smaller streams at around West 237th Street, the westernmost and primary stream along modern Tibbett Avenue feeding into the Spuyten Duyvil, and the easternmost along the right-of-ways of the Putnam Railroad and current Major Deegan Expressway feeding into the Harlem River.

[25][26][27] The watershed from the brook created wetlands surrounding the stream, and formed a northern extension of the Harlem River valley.

[18][21][24][30][25] During at least three glacial periods, including the Wisconsin glaciation around 20,000 years ago, ice sheets advanced south across North America carving moraines, valleys, and hills across present-day Bronx and Westchester.

[29][31] Prior to European colonization, the local Lenape population utilized the brook for drinking water and fishing.

[10][13][14][24][36] The marshlands created by the brook and lake had drawn the ire of local residents and property owners, who believed them to be "unsightly and unsanitary".

[15] At the time the park was constructed, the southern portion of the Saw Mill River Parkway was built on top of the dump along the western tributary course.

[17][46] Between the 1930s and 1960s under the supervision of Robert Moses, several highways including the Henry Hudson, Saw Mill and Mosholu Parkways were constructed within Van Cortlandt Park, requiring Tibbetts Brook to be diverted into culverts under the roadways.

[14][39] In addition, pollution from upstream and the highways, and spillover of chemicals used in the golf course led to the death of fish inhabiting the lake.

[39] That year, another storm drain located at approximately Lawton Street and McLean Avenue near the Saw Mill Parkway, 1,300 feet (400 m) north of the Yonkers/Bronx border, was found to be leaking household sewage into the brook.

[8] Beginning in 2015, the Friends of Van Cortlandt Park, in collaboration with the Civil and Environmental Engineering Department at Manhattan College, monitor the Brook's water quality.

[14] The primary route proposed for bringing the brook above ground is the former Putnam Railroad right-of-way, which is currently owned by CSX Transportation but is largely abandoned between the park and the Harlem River.

The routing would provide a more natural drainage path for the brook into the Harlem River, with none of the water entering the sewer system on a normal basis.

[52] After several years of delays,[53] the New York City government agreed to buy CSX's land in January 2023 for $11.2 million.

The city still had to obtain some land between 225th and 230th streets from the Metropolitan Transportation Authority (MTA), which operated a garbage-transfer facility at that site.

[57] That June, NYC Parks and the New York City Department of Environmental Protection finalized their purchase of land from CSX.