Emsworth Locks and Dams
The Emsworth Locks and Dams are not the first set of locks and dams near this location.
As you are driving toward Pittsburgh on Ohio River Boulevard (a/k/a Route 65) near the Eat'n Park you may have noticed this blue Pennsylvania roadside marker. The marker reads:
Below this bridge was the first lock and dam built (1878-1885) on the Ohio River. This was the world’s largest movable dam yet constructed, and included the world’s first rolling lock gate and widest lock chamber. Built and operated by the U.S. Army Corps of Engineers; replaced by the nearby Emsworth Locks and Dams in 1922. (Dedicated: Saturday, July 4, 1987)
In this image Pittsburgh is to the right and the I-79 bridge is to the left.
The approximate location of the Davis Island Lock and Dam is not evident using Google Earth. The dam spanned the Ohio River from Davis Island (highlighted in magenta in lower right) to the Avalon side of the river. There was a smaller dam between Davis Island and the community of either Pittock or Stowe Township.
Since 1921 there are two dams (highlighted in yellow) that span the Ohio River. There are two sets of locks (highlighted in red) for raising and lowering vessels between the upper and lower pools. There is one dam (lower left of the image) on the back channel of the Ohio River between Neville Island and Kennedy Township. There are no locks on the back channel. The other dam (upper right of the image) is at Buzzie's Corner and spans the Ohio River between Emsworth and Neville Island.
Davis Island Lock and Dam
The Davis Island Lock and Dam Site on the Ohio river in Avalon, Pennsylvania, is the site of the former Davis Island lock that was completed in 1885.
The lock and dam existed from 1878 to 1922. The Davis Island Lock and Dam was the first dam that was constructed on the Ohio River. It officially opened on October 7, 1885. The Davis Island Dam was the largest Chanoine dam built in the 19th century, and one of the first concrete structures built by the Army Corps of Engineers.
The dam was dismantled in 1922, when it was replaced by the Emsworth Locks and Dam less than a mile downstream of the original site. It was listed on the National Register of Historic Places on August 29, 1980 and designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers in 1985.
The dam was a wicket (a/k/a/ Chanoline) dam. A wicket dam can be raised in times of low water to create a pool and lowered when the flow is adequate for navigation.
The chamber was 110 feet wide and 600 feet in length. The gate was a rolling lock that when opened was retracted beneath the railroad tracks and into the hillside and did not require space in the chamber as does the miter doors as there are at the present locks.
For additional details and images read this 181 page document.
p16021coll4_67.pdfEmsworth Locks and Dams
Construction began at Emsworth in 1919 and continued until 1922, with the locks first opening in September 1921.
The facility replaced three older wicket-type dams which were constructed between 1877 and 1915. They were: 1) the original Lock and Dam 1 on the Ohio River at Davis Island (completed in 1885); 2) the original Lock and Dam 1 on the Allegheny (1902); and 3) Lock and Dam 1 on the Monongahela (1915). Davis Island Lock and Dam was the first federally built navigation project and served as a model for the 52 wicket dams built on the Ohio River to permit reliable river traffic from Pittsburgh to Cairo, Illinois.
The Corps rebuilt and converted the dam to a gated structure between 1935 and 1938. This action raised the pool an additional 7 feet to accommodate larger, more modern barges.
There are two locks, one for commercial barge traffic that is 600 feet long by 110 feet wide, and the recreational auxiliary lock that is 360 feet long by 56 feet wide. Emsworth averages about 470 commercial lock throughs every month and 350-400 lock throughs a month on the recreational auxiliary lock.
Although it depends on water levels of the upper and lower pools the difference height between the pools is usually 16 to 18 feet.
Here are a few YouTube videos that have useful information and events that have happened at the locks and dam:
How are boats raised and lowered?
The secret to raising and lowering vessels in the locks is the same as the drains in your house -- gravity. Water has a property that it tends to seek the lowest level. There are numerous YouTube videos that explain how water drains from the upper pool into the lock chamber and from the lock chamber to the lower pool. Simply open valves and let gravity move the water.
If you want a hands-on experience with locks and dams you should visit the Carnegie Science Center. As you start to climb the ramp from the main lobby there is a water play table to the left. Here you can open and close gates and drain water from the upper pool to the lock chamber and to the lower pool. Children seem to enjoy playing with it.