Originally providing a major shipping access route along the Potomac in the 19th century, the C&O Canal is now preserved as a National Historic Park natural recreation area that runs through Maryland, West Virginia, and the District of Columbia.  To provide pedestrian and vehicle crossings as well as to divert excess water from the canal, many culvert bridges were built along the route.  They were originally constructed entirely of stone, but have gradually been converted to concrete structures covered with stonework.  At 40 feet in diameter, 80 feet long, and 25 feet high, Culvert 182 is the largest historic culvert built by the C&O Canal.  It dates from 1840 and carries the Little Tonoloway Creek under the historic canal prism and towpath.  The last major stabilization campaign occurred in 1974, after flooding caused by Hurricane Agnes. 

A recent structural assessment revealed several deficiencies, among them: separation of the voussoir stones from the barrel and large voids in the barrel at the spring line, shear cracks through individual stones along the spring line, and an increase in leaking through the culvert barrel over the previous years as well as failure of the 1970s concrete patches.

The National Park Service retained WEI to stabilize the culvert structure and reline the canal prism with a synthetic liner—work that required diverting the Little Tonoloway Creek.   Prior to beginning repairs on the culvert itself, WEI built temporary access roads to bypass the culvert bridge and the construction area.  Extensive sediment and erosion control was required because of the proximity of the earthwork to Little Tonoloway Creek and C&O Canal.  The effects to the natural environment were mitigated at all times.

The stream was diverted, one half at a time, so that the 500-foot section of the canal bed could
be reshaped and an underdrain system installed.  WEI also installed concrete termination walls and a new PVC liner system before putting the clay bed back in place.

Work on the culvert included vegetation removal, localized disassembling of the stonework and repair of the concrete liner.  Existing cavities and voids in the culvert were filled with a cementitious grout, and stone repairs were made, including patching, pinning, epoxy injections, repointing, and resetting.  Stones that were beyond repair were replaced, including a great deal of infill at the interior lining of the arch, which required careful shaping and installation for structural soundness.  WEI also rebuilt two cheek walls at one end of the culvert, which included reconstruction with existing stone as well as some replacement, and installed steel straps to stabilize the other end of the culvert.  There was a considerable amount of earthwork to provide erosion and settlement control, entailing removing material and reshaping the existing canal bed.