TBM DalisayThe Novaliches-Balara Aqueduct 4 (NBAQ4) Project— Manila Water’s largest water supply infrastructure project to date—continues to move forward, with the tunnel boring machine (TBM) Dalisay having started its journey. 

The ceremonial push-button signaling the start of tunneling was held during the celebration of the project’s one-million safety milestone on January 24, 2020.

TBM Dalisay has now progressed approximately 65 meters towards the tunnel entrance in Brgy. Old Balara, installing more than 50 rings that form the walls of the tunnel; each tunnel ring, in turn, is composed of six concrete segments. The aqueduct project will use more than 37,000 segments in its construction.

Since the 1500s, it has been a tradition to name TBMs after women as a sign of good luck for the project ahead. Other famous TBMs include Lady Bird, which dug Washington DC’s 13-mile sewer tunnel, and the world’s largest TBM, Big Bertha.

TBM Dalisay weighs 266 tons, has a cutting diameter of 3.8 meters and is 113 meters long. Designed and manufactured by Herrenknecht AG of Germany, she arrived on-site in September 2018. TBM Dalisay will be used to build a 7.3-kilometer underground aqueduct passing under Commonwealth Avenue—the first time in the Philippines for a TBM being used in an urban setting.

Awarded in August 2017, NBAQ4 will rehabilitate Manila Water’s three existing aqueducts built as early as the 1930s. Once completed and commissioned in 2022, the new aqueduct will be capable of delivering 1,000 million liters of water per day from La Mesa Reservoir to the Balara treatment plants.

NovaBala JV Corporation, composed of First Balfour (Philippines), CMC di Ravenna (Italy) and Chun Wo Engineering (Hong Kong), signed the design-and-build contract in August 2017. (Story/Photos by: Dolly Pasia-Ramos)