Bringing Water to Brookland

Inspecting the completed tunnel in 1900. Washington Star photo.

It wasn’t as if Brookland didn’t have enough water. The land upon which Brookland developed was liberally sprinkled with streams of various sizes that were gradually piped underground as the neighborhood grew. Water pressure was the problem. Most Brooklanders had wells in their back yards as the only reliable source of household water during the neighborhood’s first few years. There wasn’t enough pressure for a regular fire station, so Brookland got a chemical company when the firehouse was first built in 1901. 

The problem was the Washington Aqueduct. Started in 1853 and finished during the Civil War, the aqueduct diverted water from the Potomac River at Great Falls, which then flowed through conduits down to the Receiving (Dalecarlia) Reservoir. There it sat for a time to let the sediment settle, then continued down to the Georgetown Distributing Reservoir, where it ran through smaller and smaller pipes into the city’s offices and homes. 

Map of the Washington Aqueduct in 1864.  Click to enlarge. Library of Congress

Just like the aqueduct system of ancient Rome, the Washington Aqueduct is gravity-powered. Unfortunately the Georgetown Reservoir is relatively low-lying and as the city grew and expanded the flow often did not have enough pressure to reach the top floors of office buildings or higher elevation areas to the east and northeast. 

Designed and built by Montgomery Meigs, a brilliant Army engineer, the aqueduct was constructed using the cut-and-cover method: digging trenches through the woodland, laying conduit, then covering it over. Valleys were traversed by building bridges to carry the conduit, the one across Cabin John Creek being the most impressive.

The Cabin John Bridge, also known as the Union Arch Bridge, in 1861. It was the longest single-span masonry bridge in the world when it was constructed. Click to enlarge. Photo by Andrew Russell. Library of Congress.

When the population of the city surged in the decades after the Civil War, Army engineers, including Meigs, agreed that a new reservoir at a higher elevation was needed. Major Garret Lydecker (right), engineer commissioner in 1882, chose a site near Howard University where Smith Spring flowed. He was put in charge of connecting the new reservoir to the Georgetown reservoir. Unfortunately, Lydecker could not match Meigs in terms of engineering acumen or managerial ability. 

Instead of the cut-and-cover method, Lydecker said he could dig a tunnel through solid bedrock from the Georgetown Reservoir, beneath Rock Creek, in a straight 4-mile line to the new reservoir. 

A number of shafts were sunk, and tunneling began on what was officially known as the Washington City Tunnel. Once they got started however, the diggers found there was not solid bedrock for the entire route. Cutting a tunnel through unstable, softer rock meant lining the tunnel with a triple course of brick at considerable expense. 

Section of Lydecker Tunnel showing the various types of rock and soil. Corps of Engineers

Construction fell behind schedule almost immediately. Bills piled up. Lydecker kept wheedling Congress for more money and missed deadline after deadline. Finally in 1888 the House Appropriations Committee investigated and were shocked at what they found. Many of the tunnel sections were misaligned, and would not have met properly. In addition, the gaps between the arched tunnel and the rock above were supposed to have been filled with rubble packed in cement, but some of the cavities were “large enough to drive a coach through,” according to one of the inspectors. 

City Tunnel 750 556 90
An inspector examines the state of the Washington City Tunnel in 1888.   Army Corps of Engineers.

It was also revealed that the brick subcontractors were grossly inflating their invoices, but Lydecker had blithely signed the checks anyway. He rarely visited the digs; his oversight was almost nonexistent. Horrified and angry, Congress shut down work and abandoned the tunnel. Lydecker was court-martialed for “neglect of duty” and exiled to a posting in the far Northwest. 

1892survey map
1892 Geodetic Survey map showing the bowl for the new reservoir.   Library of Congress

But better water service was still needed. As an alternative, the board of engineers decided to add two more mains to the Georgetown reservoir in hopes of improving flow. The new reservoir, at that point named the Washington City Reservoir, had already been dug after workmen with horses and pickaxes had scraped the 38 acre bowl clean and built the dam on the southern edge. It would sit that way, with weeds encroaching once again, until in 1898 Congress finally decided to finish the Lydecker tunnel and fill the new reservoir.

Section of the Washington City Tunnel under construction in July 1899. The section of the tunnel under Rock Creek was lined with cast-iron when tunnel construction recommenced in 1898. Washington Aqueduct Division. Baltimore Engineer District

The job was finally completed in 1901, and water first flowed from the Georgetown Reservoir through the Washington City Tunnel at 9:10am on November 21, 1901, and the reservoir slowly filled. On January 8, 1902 “All connections between the tunnel, the reservoirs and the city mains were opened and the new works placed in service.” Altogether, the Lydecker tunnel cost over $2.6 million, some 2 million dollars above the original estimate.

The reservoir today

But the work was not yet done. Although water was now flowing and water pressure much improved in Brookland and other areas, it was still unfiltered. The water from the Potomac had always been somewhat turbid and fears about the spread of typhoid fever had grown exponentially in the last years of the century. Even before the Lydecker tunnel was shut down Congress authorized a study for a new filtering system. Funding was approved in 1901 and work would start on a new filtration plant a year later. That’s the next chapter of the story.


Scott, Pamela, Capital Engineers, The U.S. Army Corps of Engineers in the Development of Washington D.C.  1790-2004, U.S. Army Corps of Engineers, 2011

Ways, Harry C., The Washington Aqueduct: 1852-1992, Baltimore, MD: U.S. Army Corps of Engineers, Baltimore District, 1996

History of the Washington Aqueduct (1852-1952), Washington District Corps of Engineers, 1953

McMillan Park Reservoir Historic District, National Register of Historic Places nomination, 2008

McMillan Slow-Sand Filtration Plant, Historic Preservation Report for the Proposed Redevelopment of the McMillan Slow Sand Filtration Plant, EHT Traceries, 2014

Forty-Sixth Annual Reunion Of The Association of the Graduates Of The United States Military Academy At West Point, New York June 11th, 1915, Seemann & Peters, 1915

The Washington Aqueduct, Water Supply District of Columbia, War Department, United States Engineer Office, Washington DC, 1939

Kockritz, Justin, The Bryant Street Pumping Station and the McMillan Park Reservoir Historic District: A Question of Boundaries, School of Architecture, Planning, and Preservation, University of Maryland, 2009

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