Safe Harbor Mini-Adventure: Ice Jam

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Location: On the Safe Harbor Dam fishing platform find the high water level markers on the dam wall. 39°55’29.4″N 76°23’21.6″W.

History Brief: On January 29, 1978, a combination of ice and melting snow caused the highest level of flooding ever seen at Safe Harbor Dam. It knocked out the electrical generating system at Safe Harbor Dam and forced a shut down at Holtwood Dam eight miles downstream.

Clue: Record the height of the Susquehanna River river at Safe Harbor on January 29, 1978.

Fun Fact: Here’s a fun fact about those “high water levels.” It’s not the depth of the water to the river bottom but the height of the water above sea level.

A Brief History of Safe Harbor Dam: In the late 1920s, strangers appeared in the area of Safe Harbor with offers to buy large chunks of property. Rumors quickly spread. Soon newspaper announced that another huge hydroelectric dam was to be built in the area. Safe Harbor was to be the last of three Great Depression-era public electrification hydroelectric dams on the Susquehanna.

At 464 miles long, the Susquehanna is the longest river on the East Coast of the United States that empties into the Atlantic Ocean traveling from Cooperstown, New York to Havre De Grace, Maryland. It drains an area of more than 27,000 square miles (including roughly half of the state of Pennsylvania) and is the single largest source of freshwater flowing into the Chesapeake Bay. Unfortunately, the broad, shallow waters make the Susquehanna the longest, non-commercially navigable river in the country. But the 1,180-foot elevation change between its headwaters in Cooperstown and the Chesapeake Bay make it ideal for hydroelectricity.

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Safe Harbor Dam

Planning for the construction of the Safe Harbor Dam started in November 1929 with dirt being moved on April 1, 1930. It was to be a concrete gravity dam with a total length of 5,000 feet going shore to shore. The project cost $30 million (or $445,968,421 in today’s money) with nearly $10 million paid as wages to local laborers. The massive construction project benefited 4,000 workers who all needed jobs amid the Great Depression. Most of the men lived in temporary shelters in the ravines surrounding Safe Harbor.

Not everyone appreciated the population influx from this well-paying employment opportunity. Residents of Safe Harbor sent a petition to the district attorney charging “bootleg whiskey is being sold openly and freely and that gambling is rampant.”

The irony of the petition was probably lost on the local residents when just 79 years earlier in 1851 Safe Harbor was known as one of the “booziest” towns anywhere in the county with its five taverns, three liquor stores, and six beer halls.

Being a concrete structure, the project was going to need a lot of crushed gravel. Luckily, the required raw materials were found just one mile east of the construction site. Several nearby hillsides were gouged of rock, and a crusher plant was built adjacent to the quarry to process the stone. Some 2.3 million cubic yards of rock were excavated for the project. The support structures for the old rock crusher are still visible today in the woods near the dam.

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Stone crusher supports

From the rock crusher, a short line railroad system ran next to the stream at the bottom of the ravine to transport the stone to the worksite. Short sections of the railway are also still visible today.

The dam was completed and closed its gates for the first time on September 29, 1931. Power generation began shortly after on December 7, 1931. With the completion of Safe Harbor, it could output 265,000 horsepower and when combined with Holtwood’s 180,000 constituted one of the most significant hydroelectric developments on this continent at the time.

Today Safe Harbor generates 422.5 megawatts, 230 MW at Holtwood, and 548 MW at Conowingo. As a point of reference, the Hoover dam can produce over 2,000 megawatts of capacity.

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