Maryland spent $12 million on a fish lift in 1991 to move American shad past Conowingo Dam; decades later, annual runs remained far below the 2 million-fish target

In the spring of 1991, Maryland's Susquehanna Electric Company (predecessor to today's Constellation Energy) completed a $12 million fish lift, an elevator filled with water, on the 94-foot-high Conowingo Dam on the Susquehanna River. The mechanism was designed to lift migrating fish over the concrete barrier so they could swim upstream and reproduce. Nearly thirty-five years later which undercounts the gap between 1991 and today by roughly a decade, the fish elevator, has become a reminder of how difficult it can be to use technology to overcome nature. According to a 2025 report from the Susquehanna River Anadromous Fish Restoration Committee, cited by Bay Journal, the lift moved only 2,051 American shad through the dam that season, far short of the 2 million-fish federal restoration target.

Why a fish needed an elevator in the first place

American shad are considered anadromous species, meaning that they hatch in freshwater rivers but spend much of their lives in the open sea, returning to rivers annually in spring to reproduce, similar to salmon in the western United States. The Susquehanna River, flowing into the Chesapeake Bay, used to contain more spawning habitat for shad than any other river on the eastern coast of the United States. However, this changed after the construction of the dams.

With the installation of the Holtwood Dam near the state border in 1910, shad runs above it collapsed within a few years. The completion of the Conowingo Dam in 1928 left only around 10 miles of river accessible for shad, which previously could reach all the way up to New York. By the late 1980s, state and federal fisheries agencies had concluded, under a 1989 settlement agreement, that a fish-lift facility could help restore some of that lost habitat access. The resulting East Fish Lift, completed in 1991, was described at the time as the largest fish lift of its kind in the country.

The numbers that make this awkward

This is the unfortunate part. Based on the US Fish and Wildlife Service guidelines, the fish passage target for adult American shad in the Susquehanna is 2 million fish annually, a figure meant to be a clear sign of a recovered fish population. While numbers of shad fish started rising a bit after the completion of the fish lift, reaching roughly 193,000 fish in 2001, this number has been dropping again, and occasionally drastically. In one recent spring, the fish lift recorded an all-time low of 8,341 shad, and invasive northern snakeheads lhave periodically forced operators to shut the lift down or modify operations mid-season.

Fish ladders were the 1990s answer. Attitudes have shifted since

Nancy Butowski, manager of Fisheries Management Plans and Fish Passage at the Maryland Department of Natural Resources, has pointed to a shift in thinking among state fisheries managers. “In the 1990s, it was focused on providing fish passage through ladders,” explained Butowski, “but fish passages are not 100 percent efficient. Now, we prefer dam removal.” Some of the region's better-performing fish ladders, such as those on the upstream Susquehanna dams, have been estimated in agency studies at around 30 percent passage efficiency, though efficiency figures vary by structure and by year and should be attributed to the specific monitoring report being cited.

So what happens now

No one is talking about demolishing Conowingo, as it continues to supply power to roughly 165,000 homes in Maryland through its hydroelectric facilities. There won’t be complete removal like the other small-scale projects within the watershed area. Rather than abandoning lift technology, the state and the dam's current owner have doubled down on it: in October 2025, Maryland reached a new $340 million agreement with Constellation Energy (Conowingo's owner) that includes an expanded fish lift and requires the company to trap and truck up to 100,000 shad and 100,000 river herring past Conowingo and three upstream dams each year: an acknowledgment that lift-and-truck operations, not passive fish ladders, remain the near-term strategy, even as dam removal stays the longer-term preference for smaller structures elsewhere in the watershed. The fish lift at Conowingo Dam may be the kind of a perfect metaphor for a generation saddled with all kinds of infrastructure investments that cost a lot of money and were done in the spirit of doing good but that ultimately under-delivered.