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Boring but Essential!

When you’re planning to build some of the world’s most spectacular and challenging tunnels, you need to know ahead of time what you’ll be digging through. Is it soil, sand, or stone? Is the stone strong and secure or friable and likely to collapse? To know what the bedrock is like, you need a drill rig to dig it out from hundreds of feet below the surface. The drill extracts geological core borings, cylindrical samples that provide a cross-section of subsurface conditions and let engineers know whether the area is good for tunneling and what construction methods should be used. The drill bits are tubular and loaded with shot or embedded with diamonds to cut around the core, like a drinking straw plunging into a milkshake (except really, really hard!).

By

New York City Department of Environmental Protection

Morningside Park at 110th Street and Manhattan Avenue

City Water Tunnel No. 1 was the first to bring Catskill water to the people of New York. Geological test borings helped plan its course. This shot drill combined shot and water under pressure to cut around the core samples.

401 West 123rd Street

A Keystone rig drilling test borings on Morningside Avenue.

56 Hester Street

Sheds housing drill rigs, like this one, popped up on the Lower East Side in 1910 to collect core samples of rock from hundreds of feet under the busy sidewalks.

271-273 Broome Street

Another shed, and piles of drill rods and casings on the sidewalk in front of a grocery.

Harlem River Drive and 156th Street

This wheeled model along the Harlem River Speedway was described as a "portable" drill rig.

200 Clinton Street

This drill rig appears to have offered some entertainment for passersby.

Keap Street and Lee Avenue

By the early 1920s, planning was underway for the second City Water Tunnel. The drill rigs looked a little different, but the public could still walk right up and examine operations.

731 Meeker Avenue

A typical diamond drilling rig.

50th Avenue and 39th Street

A "portable churn drill" digging into Long Island City.

Berrian Boulevard and Steinway Street

Tunnels go under rivers, which means borings must be taken from them, too, adding the challenges of tides and waves.

High Service Pumping Station

Thousands of core samples were stored for decades in the Jerome Avenue Pumping Station. Cores were labeled and placed in long wooden boxes, then stacked on special shelving.

Roosevelt Island Bridge

In the 1960s, many, many test borings were made in planning City Water Tunnel No. 3. This DeLong drill rig on the East River has a notably more robust construction than earlier rigs on water, with legs fixing it to the river bottom.

Washington Bridge

Wooden boxes for storing the geological core samples are in the foreground of this photo taken on a DeLong drill barge, Every sample was carefully labeled and tracked.

1428 FULTON STREET

City Water Tunnel No. 3 test boring cores from Westchester County, the Bronx, Manhattan, Queens, and Brooklyn were stored at 1428 Fulton Street. The weight of all that stone required consideration of floor strength as well as space.