Side Quest: Explore the ruins of the Colemanville Water & Power Company Dam

Last month, Randy Moyer on the Uncharted Lancaster Facebook group shared some great pictures of the Colemanville Water & Power Company plant and its dam breach from March of 1926.

I wanted to share those images here and provide details on how to locate the remains of the dam.

Dam breach at the Colemanville Hydroelectric plant on the Pequea. This photo was taken on March 17, 1926.
Dam breach at the Colemanville Hydroelectric plant on the Pequea. This photo was taken on March 17, 1926.

On a side note, March is apparently a tough month for Lancaster County. On March 8, 1904, an ice jam on the Susquehanna erased river towns from the map. Click here to learn more. Let’s not forget March 2020, when things in Lancaster and most of the planet came to a screeching halt.

Colemanville Water & Power Company

Located along the Pequea Creek upstream from the Colemanville Covered Bridge are the ruins of the Colemanville Water & Power Company. It was a steam and water power station that supplied power for the Lancaster & York Furnace Street Railway Company. The trolley company ran a line from Millersville to Pequea. Click here to learn more about the Pequea Trolley.

Trolley along the Pequea Creek between Martic Forge and the town of Pequea. 

The power plant also provided electricity to the village of Pequea located about 2.5 miles away. It was built in 1905 and locally owned until it was sold to the railway company in 1911.

Colemanville Water & Power Company hydroelectric powerplant with trailrace visible.

The dam was a rock-filled timber crib structure backed with earth on the upstream side to a slope. The reservoir was 1.1 miles long and eventually silted up to be almost entirely filled. Twenty-inch flashboards were used to secure the pondage and head.

Photo of the hydroelectric dam before its destruction.
Photo of the hydroelectric dam before its destruction.

The headrace was about 450 ft long formed by an embankment parallel with the hillside. The tailrace was of about the same length, is lined with masonry on the sides. Both are still visible today in the Google map below. Under light load and with flashboards, the operating head was 30 feet, but under average conditions was 28 feet.

The headrace and tailrace are still visible on satellite photos. It has been highlighted in yellow.

The hydroelectric plant consisted of two 30 inch wheels on a single horizontal shaft, which produced a combined 550 hp under the full head. They were belted to a 425 kW AC generator, which in turn operated a 17 kW exciter. The water channels were of riveted steel, the penstock was six feet in diameter, and the draft tubes flaring from 4 to 5 feet in diameter.


In March of 1926, on or before the 17th, the Pequea Creek broke through the dam. See here in these before and after photos.



Here’s a photograph showing the construction of the dam. It looks down stream from above the dam towards Colemanville.

According to Kraig Kambic, in an Uncharted Lancaster Facebook group comment, said that’s not the last time the dam got breached. It failed again about six years later, but that time the power company couldn’t get permission to repair it. Click here to read more about the Colemanville and its Water & Power Company.

Visiting the Ruins

While the foundations of the powerplant on the Conestoga Township side of the creek are marked no trespassing, you can see what remains of the dam on the Pequea Township side along the Trolley Trail. Here’s the GPS location of the dam.

You can access the Trolley Trail two different ways. The short way is by parking near the Colemanville Covered Bridge. From the parking area, you are only 700 feet away from the dam foundation.

Colemanville Covered Bridge is found near the intersection Fox Hollow Road and Pequea Boulevard. However, parking near the bridge is tricky, with plenty of No Parking signs visible. Fishermen are often seen parked in the area highlighted in red on the map below, so that’s a safe bet. That’s where I park when I go. Click here for directions. UPDATE: This area has recently changed to no parking. At least one group of kayakers reported being towed.

Parking area near Colemanville Covered Bridge.

The longer way is parking at the site of the former Martic Forge Hotel and hiking the 1.2-mile Trolley Trail to the dam ruins. You can park near the intersection of River Road and 324. Click here for directions. 

The parking area is highlighted in red and the trail in dotted white lines on the map below. The trail is clearly marked and well worn. You can’t miss it. While you are hiking the Trolley Trail, consider completing the Pequea Trolley Adventure.

Parking area for the Pequea Trolley Trail at the former Martic Forge Hotel.

Of course, should you visit the site of the former dam, I would use my favorite quote from the National Lampoon’s Vegas Vacation. 

Welcome, everyone. I am your dam guide, Arnie. Now I’m about to take you through a fully functional power plant, so please, no one wander off the dam tour, and please take all the dam pictures you want. Now, are there any dam questions?

Expanding your Adventure

If you are looking to expand this side quest with a more extensive adventure, check out the Pequea Trolley Adventure, the Colemanville Covered Bridge Adventure, and Suzy’s Hole Geocache.


2 thoughts on “Side Quest: Explore the ruins of the Colemanville Water & Power Company Dam

  1. The hydro portion of the plant consisted of two 30” wheels on a single horizontal shaft, developing together 550 hp under full head. They were belted to a 425-kw AC generator. The penstock was 6′ in diameter and the draft tube 4-5′ The steam portion, was capable of 600hp coupled to a 400-kw 3-phase , 11,000v generator. with a reserve 300-kw DC generator.

    Water Resources Inventory 1913

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