"Aerial View looking southeast, showing [Fairmount Dam,] Waterworks site and Philadelphia Museum of Art on hill." HAER
Fairmount Dam, 1819-1821
Schuylkill River at Fairmount Avenue, Philadelphia PA
© Jane Mork Gibson,
Workshop of the
World (Oliver Evans Press, 1990).
The decision in 1819 to
construct a dam at Fairmount presented a challenge that
had not been undertaken prior to that date. The river was
wide and the current very fast. The Schuylkill River
before the construction of the Fairmount Dam in 1819-1921
was a fast-flowing river subject to periodic freshets
caused by rainfall over its extensive drainage area.
After the dam was constructed, the river has remained
fast-flowing, but the current is not as easily seen
because of the six-mile pond created above the dam which
gives the false impression of quietness, but is much
respected by the rowing clubs and canoeists using the
river.
When the Watering Committee made plans to convert the
Fairmount Water Works to a water-power pumping station,
it was necessary to arrange for a dam to be constructed
across the river near the site. The Schuylkill Navigation
Company had been chartered in 1815 and was in the process
of making the Schuylkill a navigable waterway as far as
the coal fields up the river. This involved a series of
canals, locks, and dams. In 1819 the Navigation Company
was in the process of completing the Flat Rock Dam at
Manayunk, and the contractor was Ariel Cooley of
Chicopee, Massachusetts.
The city purchased the water power rights at the Falls of
the Schuylkill—the natural fall line of the
river—from Josiah White and Joseph Gillingham for
$150,000. Construction of Fairmount Dam would back the
water up for six miles and cover the falls as well as
inundate some of the islands in the river. Under the
agreement, in addition to the dam, the Watering Committee
also had to build a canal and locks for the Schuylkill
Navigation, and these were to be turned over to that
entity upon completion.
Proposals for the dam were received, and a contract was
signed with Ariel Cooley to build the dam, the canal and
locks, and also the head arches and mill race. He started
work on April 18, 1819.
Most of the river bed was rock, but the depth varied. The
dam was designed as an over-fall and was 1204 feet long,
built of cribs of large hemlock logs filled with stone
and planked over with oak plank, running up and down
stream, which were sunk in the river and fastened to each
other and to the rock bed. At the eastern end there was a
stone pier joining it to a mound dam 270 feet long and
150 feet at the base, 12 feet at the top, which was 15
feet higher than the over-fall dam. The mound dam was
fashioned of earth and quarry spalls, and was built on
the part of the river bed that had 11 feet of mud above
the rock bottom. It was calculated that it would be too
difficult to anchor cribs in that location. Beyond the
mound dam were three head arches 104 feet overall,
situated at the entrance to the millrace which had to be
cut out of solid rock.
Cooley's dam crossed the river diagonally, upstream,
turned at an angle near the western shore, providing a
large over-fall, and joined the head pier of the canal
guard locks at a right angle. This design helped
protect the dam from injury from ice and freshets, both
of which were a danger on the Schuylkill. The last crib
of the dam was put in place in June 25, 1821, and the
first water flowed over it July 23, 1821.
1
The millrace,
parallel to the river on the east bank, was blasted out
of solid rock to a total width of 140 feet. It was 419
feet long, 90 feet wide, and from 16 to 60 feet deep,
allowing continual passage of 408 square feet of water to
the forebays of the water wheels in the Mill
House.
During and after construction, there were questions about
the dam's structure and reliability, and it was repaired
and rebuilt, but it never gave way, although during some
of the repairs it was found amazing that the structure
still held. In 1842-1843 the dam was rebuilt from
low tide up, and in 1865 a new crib was sunk in front of
the old dam. Because of poor workmanship, it was
necessary to place new cribs in front of the 1865 cribs,
and a new dam was built on top in 1872. Through all
these changes, the over-fall of the dam has moved 38 feet
beyond the original line of the dam and a new pier had to
be constructed to link it with the mound dam. In the more
recent past the U.S. Army Corps of Engineers has taken
over the care of Fairmount Dam, and has rebuilt the
structure with concrete.
The industrial archeology of Fairmount Dam is under
water, but its presence cannot be denied. The canal locks
on the west bank of the river were destroyed in the 1950s
with the construction of the West River Drive and the
Schuylkill Expressway. However, a remnant of the wall of
the guard lock remains as part of the fish ladder
constructed at the site in c.1980. 2
It is possible to
consider the Schuylkill Pond created by the dam as a
feature of importance to industrial archeologists. Few
Philadelphians realize the vital part played by this 1821
structure in providing the city with a recreational
facility of unsurpassable beauty and which was so
essential a part of the creation of Fairmount Park but
which was constructed for purely utilitarian purposes.
1 See notation by
Frederick Graff on "Plan
of the Mill Buildings at Fairmount, Designed by F. Graff
in 1819," (Graff Collection, Franklin
Institute).
2 See "Fairmount
Dam, Fish Ladders Site Plan, Pennsylvania Fish
Commission, 1977," (Fairmount Park Engineering
Drawings).
Update May
2007 (by
Jane Mork Gibson):
Although repairs and additions to Fairmount Dam have been
undertaken in the years since its construction in
1819-1821, the original cribs have remained as placed,
with the added support constructions before and behind.
Today water flows over the dam, which people regard as a
lovely waterfall, adding to the scenic view of the
Schuylkill. Scant water flowed over the dam in earlier
years, when the water was needed on the east bank for
powering water wheels, and on the west bank for filling
and operating the canal locks.
Originally constructed for ponding of the river for water
supply and for waterpower, Fairmount Dam no longer is
needed for waterpower, but it continues to serve the city
by providing a water supply storage area for two pumping
stations with intakes on the Schuylkill. Belmont Pumping
Station is located on the west bank at Montgomery Drive;
Queen Lane Pumping Station is located on the east bank in
East Falls, near the City Line Bridge. In addition, the
large “Schuylkill Pool" created by the dam has
provided space for sculling by the “Schuylkill
Navy," based at Boathouse Row, and for canoeing by the
Philadelphia Canoe Club, located at the mouth of
Wissahickon Creek.