The canal beside Great Falls Tavern goes dry every winter because the National Park Service drains it on purpose. Each fall the park lets the water out of the canal's watered sections to protect the stone masonry from freeze damage, and the water usually comes back in early spring. The C&O Canal Company did the same thing when the canal was still carrying boats.

The drained canal is the most visible sign of how this stretch of Potomac runs between October and March. Over the next few months, a flood repair project changes where you can park. Faucets get shut off so the pipes won't burst. The visitor center drops a day from its schedule. And the Great Falls Tavern itself now has a funded plan to begin rehabilitation.

The Water Goes First

By the park's September 28, 2026 water-level update, draining was already underway in some sections near Potomac. Other sections still held water.

The park notes that water levels can change without warning, and that construction, maintenance and weather all affect the lower canal throughout the year. The sections above Great Falls Tavern were still full in late September, and the seasonal draining routine means they will empty over the coming weeks.

The boat program has already closed for the year. The park's current conditions page lists Great Falls boat rides as "Closed for the Season." This year's offering was a launch-boat ride rather than the full canal boat experience. It was free, limited to 10 people per ride, and ticketed at the visitor center one hour before departure.

A 2019 Storm Still Shapes the Parking Plan

The parking change that matters most this fall is at Swains Lock, about two miles upstream of the Tavern at mile 16.7. The park lists the Swains Lock lot as scheduled to close beginning October 13 and stay closed for several weeks.

The closure traces back to a single day. On July 8, 2019, a flash flood from intense rainfall eroded the embankments along the Great Falls Entrance Road on MacArthur Boulevard. It also damaged the timber retaining wall around the Swains Lock parking area. The park's project page describes the planned repairs: rebuilding eroded embankments, adding drylaid stone "rockery" armoring walls, reconstructing road shoulders, installing a new drainage pipe and stabilizing stream beds. At Swains Lock, crews will remove the old timber wall and replace it with a seeded embankment. The work is being done in phases that began in 2025 and continue through 2026, weather permitting.

According to the project page, here is what stays available while the Swains lot is closed:

• Great Falls, mile 14.3, is the nearest parking downstream for towpath access.
• Pennyfield Lock, mile 19.6, is the nearest parking upstream.
• Canal Quarters at Lockhouse 21 stays accessible throughout construction.

Pennyfield has its own work underway. The park flags DC Water repairs to the Potomac Interceptor near Lock 22 and warns of possible delays on Pennyfield Lock Road.

The entrance road into Great Falls stays open during construction. Expect occasional single-lane closures with flaggers, and possible delays going in and out. This contract fixes the road's substructure, not its worn surface. The park says a separate, larger pavement rehabilitation project is in design, with construction planned for a later date. The park also notes that Great Falls, Maryland draws more than 1 million visitors a year, so keeping these access points working is a priority.

Smaller Shutdowns Along the Same Stretch

Downstream at Carderock, the same pattern applies on a smaller scale. The park lists an alternating one-lane closure at the Carderock Tunnel, starting July 27, 2026. The Carderock restrooms are closed for emergency repairs, with portable toilets in their place, and Parking Lot 1 is open at reduced capacity because a contractor is staging equipment there.

Drinking water follows the calendar too. Around mid-November, the park turns off faucets at campsites throughout the park so the pipes can dry out before they freeze and crack. The Swains hiker-biker faucet is already off. Faucets at the Great Falls Tavern restrooms and the Swains Lockhouse run on municipal water and are listed as on and potable.

The Billy Goat Trail runs on the river's schedule more than the season's. As of the park's October 9, 2026 update, Sections A, B and C are all open. Section A usually closes when the Little Falls gauge reaches 5 feet and reopens when it falls to 4.8 feet, though the park can close it at lower levels in some conditions. For current trail status, the park suggests calling the Great Falls Tavern Visitor Center at 301-739-4200 during business hours.

The Tavern's Turn

Every item above is routine maintenance or storm repair. The Tavern project is different because it is about the building itself, and the funding comes from a philanthropic partner rather than a federal road program.

In a July 31, 2026 post, the C&O Canal Trust announced a partnership with Preservation Maryland and the National Park Service to support long-term preservation and rehabilitation of the Tavern. The Trust also announced a major philanthropic campaign and said the first phase of work was planned to begin this year as "early rehabilitation projects." The building has a long history as a gathering place. As Crommelin House, its second-floor rooms rented for 25 cents. A third-floor "honeymoon suite" cost 50 cents and required a marriage certificate. The National Park Service acquired the building in 1938.

The campaign launched at Park After Dark on September 19, where the Tavern was featured as the evening's Spotlight Fund. On its Park After Dark page, the Trust reports that the event raised nearly $250,000 overall. Separately, it says it will invest $150,000 to launch the first phase of the Great Falls Tavern Initiative. The Trust has not published which parts of the building the first phase covers or a construction schedule. As of October 9, 2026, the National Park Service lists the visitor center as open.

The initiative also takes over work that another group did for more than 50 years. The Friends of Historic Great Falls Tavern, founded in 1973, raised over $500,000 toward the Charles F. Mercer canal boat, which launched at Great Falls in 2006. In 2025, the Friends' board voted to dissolve as an independent nonprofit and hand its mission to the Trust. In the Trust's announcement of the transition, Trust President and CEO Lauren Riviello said:

"While the Friends' chapter is closing, their story is not ending. The Trust is honored to carry forward their mission."

The Trust's July post credits the Friends' long stewardship, along with individual donors, for making the initial rehabilitation projects possible. The Trust has already set the next Park After Dark for September 18, 2027.

The Calendar From Here

The schedule change on December 1 affects one day. The Great Falls Tavern Visitor Center is normally open Wednesday through Sunday, 9 a.m. to 4 p.m., and closed Monday and Tuesday. From December 1 through February 28, it is open Thursday through Sunday at the same hours, so Wednesday visits stop until March.

For guests coming in from out of town, the park's fee page lists a $20 private-vehicle pass and a $10 pass per person age 16 and older arriving on foot or by bicycle. The park does not accept cash. That page was last updated in August 2025, so check the rates before you go.

The Tavern has been part of Potomac's riverfront since the canal era, and its history is closely tied to the neighborhood. If you are thinking about how a place like Great Falls figures into your own plans for home in Potomac, Kari Wilner would be glad to talk it through. Request a private consultation or home valuation whenever the timing suits you.