CONTRACTING Shafts NYC WATER TUNNEL SHAFTS 21B AND 22B BROOKLYN, NY (1991) KiSKA-USA made a vital contribution to the completion of New York City's $4 billion water system expansion with the timely construction of two 650-foot deep access shafts. Like much of KiSKA-USA's work, construction of these shafts was undertaken in a dense urban setting where the solution to complex logistical and regulatory requirements was the key to the project's ultimate success. Typically, KiSKA-USA's engineers work with proven systems and technologies to minimize costs and avoid delays. For the New York City water system, soft soil around the shafts was fully stabilized through ground freezing techniques down to bedrock at a depth of 220 feet below grade. Despite the risks associated with large, subterranean construction projects, KiSKA-USA's safety controls insured a perfect safety record for the duration of the project.