Platinum Award for the Catskill Aqueduct Optimization Program

In addition to supplying NYC, the Upper Catskill Aqueduct supplies communities in the four counties through which it travels. Improvements made maximize supply during shutdowns of other critical system components such as rehabilitation of the leaking Delaware Aqueduct.

Interior inspections of various aqueduct sections were conducted. The inspections assessed the possibility of localized restrictions, and supported development of the hydraulic model. They also provided an opportunity to measure biofilm thickness along the aqueduct length.

This construction photo taken around 1918 shows a typical cross-section of an Upper Catskill Aqueduct cut-and-cover section. Visible in the distance is the partition wall where temporary barriers can be used to isolate segments and maintain partial service during rehabilitation to minimize customer impacts.

Analysis of aqueduct wall deposits found high concentrations of iron and manganese, consistent with analyses reported previously. However, unlike the earlier analyses, biological testing confirmed the presence of biofilm containing sheathed filaments, typical of manganese oxidizing bacteria, which can cause friction losses in the aqueduct. Oxidized metals appear as dark brown particles in these magnified images of sheathed manganese oxidizing bacteria. (Images are shown at increasing levels of magnification from left to right.)

(NEW YORK, NY – March 26, 2012) – The American Council of Engineering Companies – New York has bestowed the 2012 Platinum Award to the Catskill Aqueduct Optimization Program.

More than 74 miles long, the Catskill Aqueduct serves 14 communities in four counties in addition to providing a third of New York City’s water supply. The Optimization Program identified cost-effective improvements and implementation strategies to restore up to 70 mgd of capacity lost due to increased friction from biofilm growth on the interior surface.

Hazen and Sawyer developed an innovative approach built on historical hydraulic assessments and operating history, augmented with extensive field work and hydraulic modeling, to define current and potential aqueduct capacity. Hydraulic surveys at more than 40 locations and continuous water level monitoring at eight locations provided valuable information on aqueduct performance and friction factors. The results of these studies provided a basis for identifying a range of treatment options, including chemical addition, as an essential component of capacity improvement and maintenance.

The project enhanced NYC water system reliability without construction of costly new infrastructure. It also defined potential capacity restoration, prioritized improvement work, provided effective improvement methods, and included careful scheduling to minimize service disruptions to the communities that draw from the aqueduct.

Since our founding in 1951, Hazen and Sawyer has focused on two things: providing safe drinking water and controlling water pollution. Our range of services encompasses the planning, design, and construction management of water and wastewater-related projects – from clean water treatment, storage, and distribution to wastewater and stormwater collection, treatment, and reuse.

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