Spuyten Duyvil Creek was originally a narrow tidal strait connecting the Hudson River to the west and the headwaters of the Harlem River to the east; both of those were fed by the waters of Tibbetts Brook flowing south from the Bronx. When the Dutch settlers arrived they found its tidal waters turbulent and difficult to handle. Though its tides raced, there was no navigable watercourse joining it with the headwaters of the Harlem River, which flowed in an "S"-shaped course southwest and then north into the East River. Steep cliffs along the Spuyten Duyvil's mouth at the Hudson prevented any bridge there, but upstream it narrowed into a rocky drainage. Prior to the development of the Bronx, the creek was fed by Tibbetts Brook, which begins in Yonkers, Westchester County and intersected with the creek at modern West 230th Street. The brook currently ends above ground within Van Cortlandt Park, emptying into the Harlem River system at the Wards Island Water Pollution Control Plant via underground sewers.