NEW YORK CITY — New York City Environmental Protection (NYDEP) Commissioner Carter Strickland has announced the start of a year-long pilot study to evaluate a new method of sealing cracks in concrete water pipes that could eventually help stop leaks and maintain the Delaware Aqueduct, an 85-mile water tunnel that conveys approximately half of the drinking water from four upstate reservoirs to more than eight million people in New York City, and one million people in Ulster, Orange, Putnam and Westchester counties. A Syracuse University lab test, funded in part by DEP, demonstrated that introducing lime and other chemicals into water flowing through concrete pipes can effectively seal hairline cracks and reduce leaks.

In August, DEP began a $4 million proof of concept experiment at the Rondout Reservoir that will simulate actual conditions in the Delaware Aqueduct and determine if this new leak sealing technique can be applied on a larger scale.

Chemical combinations being examined include: lime, lime with carbon dioxide, “liquid lime” which uses calcium chloride, sodium hydroxide and carbon dioxide.

“The Delaware Aqueduct is a critical link between our reservoirs and the nine million New Yorkers who rely on the water it supplies,” said Strickland. “This study is one of many investments we are making to ensure future generations have access to this precious resource, and a demonstration of our commitment to exploring every option to stop leaks in the aqueduct.”

The pilot project is part of Water for the Future, a comprehensive $2.1 billion plan to fix the leaking Delaware Aqueduct. The plan includes construction of a three-mile bypass tunnel around a portion of the aqueduct that is leaking in Roseton in Orange County, and repair work to sections that are leaking in Wawarsing in Ulster County. DEP plans to break ground on the bypass tunnel in 2013, and expects to complete the connection to the Delaware Aqueduct in 2021.