Best Landscape/Hardscape/Urban Development: Daylighting of Saw Mill River at Larkin Plaza
This $18.8-million project brought to light a portion of the Saw Mill River that had for decades run under a downtown parking lot in Yonkers, N.Y. When completed in September 2012, the parking lot was transformed into a three-acre public park with waterfalls, a footbridge and a tidal basin.
The project involved construction of an 800-ft-long river diversion and river walk at Larkin Plaza and the erection of a pedestrian bridge and boardwalks. It overlooks an amphitheater and vegetation and is considered an oasis situated amid multiple civic buildings, the historic Phillipse Manor and significant traffic volume.
The existing sanitary and stormwater systems within the project area included both separated and combined systems. Working closely with utility companies, the team prevented damage and service interruptions.
During construction, improvements were also made to the aged utility infrastructure surrounding the project. Groundwater was monitored daily for elevation changes through a de-watering system that included a 1,500-linear-ft header pipe with 250 well points at a depth of 25 ft. For five months, a total of 21 million gallons of water was pumped from the project site. Structural chambers were made for the confluence and diversion chambers.
Among the project's innovations was the use of an underwater video camera to provide guidance to a diver who placed grout bags where the outfall from the Saw Mill River met the Hudson River. This method, along with the use of 3D modeling, helped the team unearth and physically locate the existing concrete flume and enclose the river along active streets and occupied buildings.
By "daylighting" the river, the team also "opened up the community," said one Best Projects judge. "There are multiple benefits to these [types of] projects," said another judge. "Instead of looking at an old parking lot that used to cover the creek, they brought the water up to the people. It is transforming."
Daylighting of Saw Mill River at Larkin Plaza, Yonkers, N.Y.
Owner City of Yonkers
General Contractor ELQ Industries
Lead Designer Paulus, Sokolowski and Sartor
Project Engineer PS&S Engineering Inc.