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Bear Traps in the Lehigh River

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Did you know that Bear Traps once existed in the Lehigh River? Not the kind which actually caught wild bears, but Bear Trap Dams which were an ingenious river lock system used on the Lehigh River from 1819 to 1826. A total of 12 of these Bear Trap Dams were used between Mauch Chunk (present day Jim Thorpe) and Easton, before the Lehigh Canal system came into use.

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With the discovery of anthracite coal in 1791 near the town of Mauch Chunk there was a need to find an efficient and cheap way to deliver coal to the nearest market which was in Philadelphia. Adequate roads did not exist at that time so rivers were the best option to transport coal. The worst river to navigate was the Lehigh.

The shipment of coal was a slow and hazardous procedure. The coal was shipped on wooden boats called arks which could only be used when the river was high enough. But many of these arks never made it due to the dangerous river conditions. It was said that more coal wound up lost in the Lehigh’s cold water than in the stoves and furnaces in Philadelphia.

One of the biggest anthracite users at this time was the firm of Josiah White and Erskine Hazard, two Philadelphia businessmen. In 1818, they started the Lehigh Navigation Company and worked to improve the river at the mouth of the Nesquehoning Creek. They had planned to narrow the channel to raise the water for boat travel but found out that there still wasn't enough water. In order to solve this problem, Josiah White invented a new type of lock system which became known as a Bear Trap Dam. These locks were named by the workmen whom applied this name to elude the curiosity of persons who teased them with inquiries as to what they were making.

White and Hazard’s bear trap dams were wing dams with a sluice gate in the middle that could be closed by rising and opened by lowering. When the gate was closed, river water backed up behind the dam and formed a temporary pond. Coal-filled arks eighteen feet wide and twenty-five feet long were linked together in a line upstream of the dam. When the pond was full, the sluice gate was lowered, creating an artificial “freshet,” or flood, that swept through the sluice opening and carried the arks downstream. The process was repeated at dams downriver until the arks finally reached the deeper, wider, Delaware River in Easton.

White and Hazard’s one-way Bear Trap system operated until 1826, when 31,280 tons of coal floated down the Lehigh River. With increased demand for coal and the loss of prime timber in the mountains which was used to make the arks, the two men began constructing the Lehigh Canal in 1827, which would be a two-way transportation system. The canal officially opened on June 29, 1829.

In January of 1841, there was a flood on the Lehigh River which destroyed many locks and dams. In time most of the canal was repaired and coal shipments continued. But, then in June of 1862, another flood ripped through the dams and locks on the Lehigh Canal. The Mauch Chunk Dam broke killing more than 150 people. Damage was so bad that most of the canal between White Haven and Mauch Chunk was destroyed.

The Lehigh Valley Railroad which started operations in 1855 had slowly begun to replace the amount of heavy loads shipped on the canal. This plus the disastrous floods convinced the company not to rebuild the upper canal. The canal did continue to operate though, but as the years went by shipments on the canal decreased. Shipping on the canal finally stopped in 1931 except for some activity in Carbon County with canal boats hauling coal to the New Jersey Zinc Company up to 1942 when another devastating flood ended travel in the Lehigh Canal for good.

On the Freemansburg section of the D&L Trail there is an observation deck located along the canal towpath on the Lehigh River. The remains of one of these Bear Trap Dams are visible in the river below this observation deck which was built by Eagle Scout Jonathan Yu of Bethlehem Township. Other traces of this type of dam are visible between Slatington and the Lehigh Gap.



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