Westchester County operates a 54-inch diameter force main that conveys wastewater from the North Yonkers Pump Station to the Yonkers Joint Treatment Plant. This force main had experienced excessive surge pressures near a 90-foot deep inverted siphon beneath a sugar factory, which caused appurtenances to be dislodged from the force main. In order to alleviate this problem, the County decided to install 10 vacuum-air release surge vaults to relieve the excess pressure.

The B. Thayer survey team assisted in this effort by providing design grade topographic and boundary mapping of the 9 proposed vault locations that were closely adjoining private property. Our field surveyors created a horizontal and vertical control network across the project work area using GPS and conventional survey technologies. This site network was then referred to NAD83/CORS2002 and NAVD88 datum. Detailed topographic mapping of all the work areas was then undertaken. All major improvements were located along with enough topographic data to generate contours on a one-foot interval from a Digital Terrain Model (DTM).

Additionally, a right-of-way map was generated to depict the existing right-of-way, property boundaries, and easements affecting all the locations throughout the project limits.

North Yonkers Force Main Surge Chambers Surveying Services

Location: Yonkers, NY

Client: Westchester County Department of Public Works