Restoring the Rest of Peirce Mill
About two hundred years ago, Isaac Peirce started building a grist mill along Rock Creek. In 2020, the Friends of Peirce Mill and the National Park Service will continue rebuilding this historic “flour factory.”
Not long ago, Peirce Mill wasn’t grinding grain at all. After the water wheel’s main shaft broke in 1993, the millstones stood still for almost 20 years. In 1997, the Friends of Peirce Mill began working closely with the National Park Service to restore the mill. Thanks to generous community and federal support, Peirce Mill has been grinding corn since 2011.
The water wheel and millstones were restored in 2011, but they are only part of the mill’s machinery. All four floors of Peirce Mill were once part of a giant machine, inspired by Oliver Evans’ revolutionary 18th-century milling system. In 2019, the Friends of Peirce Mill completed a study of the entire Evans system and, with matching funds from the federal government, began repairing the mill’s elevators.
As Peirce Mill enters its third century, a restoration of all four floors, including parts of the Oliver Evans milling system, will begin.
The Oliver Evans Milling System
Oliver Evans invented his new milling system in the late 18th century. Before Evans, millers carried heavy sacks of grain up and down stairs. And children worked as “hopper boys,” raking freshly-ground flour to dry before sifting.
In the Evans system, waterpower replaced manual labor. Machines cleaned and ground the grain, then dried and sifted the flour. Chutes and elevators moved grain and flour between floors.
For his invention, Evans received the third patent ever issued by the U.S. government. Isaac Peirce used some of this new technology when he built his grist mill almost years ago.
In the 19th century, Peirce Mill was a mechanical marvel—a giant, water-powered machine, connected by gears, belts and pulleys. The Friends of Peirce Mill and the National Park Service are working to start those wheels turning again in the 21st century.
Inspiring the Next Generation of Engineers
Technology has evolved since Oliver Evans invented his milling system. But a 200-year-old machine can help interest young people in engineering.
At Peirce Mill, students see a water wheel at work and watch giant wooden gears turn. Unlike a cell phone or car, a mill is a machine that children can easily understand.
And students don’t just watch the mill work. On school field trips, they grind and sift grain by hand, and experiment with water power. Children also experience beautiful Rock Creek Park and envision what their city looked like 200 years ago.
In 2019, the Friends of Peirce Mill and the National Park Service developed six new field trip programs to help students understand the mill, its history, and its technology. These include STEM-focused pre- and post-visit materials to help teachers bring the mill into the classroom.
Waterwheel and Millstone Restoration Completed in 2011
Peirce Mill re-opened on October 15, 2011, milling grain for the first time in 18 years.
Before the mill wheel shaft split apart in 1993, the mill had informed generations of Washingtonians about early American technology and the agrarian past of the Nation’s Capital. The restoration project represented a new era: for the first time, a public-private partnership took responsibility for repairing—and is now managing—a major destination within Rock Creek Park.
The non-profit, volunteer-led Friends of Peirce Mill (FOPM) was formed in 1997 by Richard Abbott, a former docent at the mill, when it became apparent the National Park Service didn’t have the funds to restore the mill. FOPM retained Quinn Evans Architects and Robert Silman Associates (structural engineers) to perform a series of architectural and engineering studies of the structure. At the same time, FOPM engaged Derek Ogden, a leading millwright and mill restoration expert, to examine the condition of the wooden milling machinery and to recommend repair or replacement of parts required to make it operational.
Restoration work began in 2001, when the first repairs were made to the internal structure of the building, including the columns and beams which support the first floor, and selected floor joists. Ensuring the safety and stability of the mill itself was a critical first step before work could begin on the mill’s machinery. Most of this phase was completed by 2004.
Beginning in 2004, work began on repairing and/or replacing elements of the wooden milling machinery, including the hurst frame (on which the main gears and shafts are mounted), water wheel, main shaft, and internal gears and shafts. Work on the mill building continued.
In 2010, the National Park Service received $2 million for the restoration of Peirce Mill as part of the economic stimulus package authorized by the American Recovery and Reinvestment Act (ARRA) of 2009. FOPM raised an additional $1 million through donations and grants, which leveraged the ARRA funds to complete the effort to bring the mill back into operation. The project included extensive landscaping work around the mill site, including removal of the old asphalt parking lot and comfort station, which made the site more closely resemble its appearance in the 19th century. A bus parking area was built just uphill from the visitor center where school buses can safely offload students visiting the mill. Construction took place from 2010 to 2011.
One element of the ARRA project was installation of the mill’s pumped water system, designed by architects retained by FOPM. The system uses city tap water to move the mill wheel and mill stones. The closed system re-circulates the water rather than releasing it into Rock Creek. A stone enclosure that partially follows the historic path of the mill’s headrace was constructed to contain the water pumping system. Stones were laid in the ground to trace the rest of the path of the historic headrace from Rock Creek.
A grand opening for the restored mill was held by the National Park Service and FOPM on October 15, 2011, with Steve Whitesell, Director, National Capital Region in attendance. Corn grinding demonstrations have been held regularly since that time.
While the waterwheel and millstones are turning again, work to fully restore the mill is not yet finished. FOPM continues to spearhead efforts to restore the mill and the Peirce estate as closely as possible to their historic appearance.
In 2012, FOPM planted the first trees in a re-creation of the Peirce Plantation apple orchard. In partnership with the park service, FOPM uses the orchard to teach schoolchildren about apple horticulture and history, and the nutritional benefits of fruit as well as whole grains. In the autumn of 2014 and spring-summer of 2015, Casey Trees volunteers and Peirce Mill interns planted more fruit trees and began the restoration of the wooded area on the slope behind the orchard. Over two dozen apple and pear trees (including several of the prized Albemarle Pippin apple variety) now grow on the hillside west of the mill, where an historic orchard once stood. Two dozen oaks, maples, pines and other native trees were also planted on space cleared of Multiflora Rose thickets and other invasive species.
In May 2016, the barrel hoist, a mechanism that moved barrels and sacks of flour between floors during the mill’s commercial operation, was brought back into operation. Like other historic machinery inside the mill, the barrel hoist is powered entirely by the waterwheel. Additional mechanisms that await future restoration include the grain elevators, hopper boy, bolter, grain cleaner, and many chutes, gears, belts, and pulleys.