3 July 2024
What occurs when a dam is faraway from a river? We’re about to search out out on the Monongahela River at Elizabeth, PA. On 10 July, climate and river allowing, the US Military Corp of Engineers (USACE) will start eradicating Locks and Dam 3, also referred to as the Elizabeth Locks and Dam. Inbuilt 1907 is among the oldest such constructions within the U.S.
This animation from USACE reveals how will probably be finished.
Ideally the removing of a dam would restore the river to a extra pure state however Pittsburgh’s three rivers are a collection of swimming pools — like lakes — created for navigation by quite a few locks and dams.
The dam at Elizabeth is 12.6 miles upstream from Locks and Dam 2 at Braddock and 23.8 miles downstream from Locks and Dam 4 at Charleroi. When the primary hole is made within the Elizabeth dam it is going to take 3 days for the water degree to stabilize right into a pool 36.4 miles lengthy stretching from Braddock to Charleroi. No, the Monongahela River won’t revert to a pure state however there might be different results.
As demolition continues on the remainder of the dam, its removing will launch sediments reminiscent of silt, clay, sand and gravel which have constructed up behind the dam for greater than 100 years. Contemplating Pittsburgh’s industrial previous, the sediments might include toxins reminiscent of heavy metals and PCBs. My guess is that this may largely have an effect on the pool right down to Braddock.
Ultimately the turbidity will calm down and the Monongahela River will attain a brand new regular.
How a lot will the dam removing have an effect on the Mon at Duck Hole? We’ll have to look at and see.
Location of Locks and Dam 3 is on the Google map under. Learn extra concerning the challenge at The Waterways Journal.
