After years of controversy, debate, and cost overruns, the Croton Water Filtration Plant in the Bronx is expected to be complete next year. The city’s first filtration plant was originally estimated to cost $1.3 billion but is now approaching $3 billion. The plant will be able to process 250 million gallons of water a day and is capped by a 9-acre driving range that complements the Mosholu Golf Course adjacent to it in Van Cortlandt Park. In the coming months, final aspects of the park design will be vetted at community board hearings while the Department of Design and Construction continues to oversee the construction of what will be the largest contiguous green roof in the nation.
Designed by Grimshaw with Ken Smith Landscape Architecture, the filtration plant and park needed to balance complex infrastructure and a highly public parks program; intense security was also a factor. The project is being delivered in phases, starting with below-grade infrastructure for the plant and followed by surface work including a green-roofed driving range, the security entrance, and a chemical fill station.
While Grimshaw designed the above grade structures and landscape, AECOM/Hazen & Sawyer are responsible for the design of the underground Water Treatment Facility including its interior architecture. Grimshaw worked closely with the Department of Environmental Protection for the most sensitive aspects underground. A security building with state-of-the-art 3-D X-ray machines will screen arrivals. The buildings for chemical deliveries are about the size of two 18-wheeler trucks. Four one-foot-thick security doors protect the interior. An impressive concrete pavilion processes workers and visitors going underground. A clubhouse and irrigation pond are also part of the plan.
The park design is akin to fitting a round peg atop a square hole. The plant is square, and the driving range is a grand circus that seems to screw down into the existing landscape. The driving range/rooftop includes turf conditions found on your average course, including undulating hills and sand traps. Nine to twelve inches of topsoil are layered over geoform mounding and drainage management systems; only organic fertilizer will be used. While the public will be able to hit balls onto the grass and access the clubhouse, channels of water, like moats, will keep golfers off the green. No one except highly-vetted Parks employees will have access to the roof for maintenance.
The 100-foot depth of the plant creates a regional low that requires sub pumps to keep out groundwater from nearby wetlands and water runoff from the driving range. The circular moats that surround the site for security also store excess water. The moats are complemented by huge nets that keep golf balls in and interlopers out. The captured water is then used to irrigate Mosholu’s 9-hole golf course. At Croton, the green roof is meant to send a message about responsible water management.