Water power

There is a curious factoid about energy production in the United States that I am fond of: in spite of great advances in technologies such as solar and wind, the proportion of electricity in the U.S. generated from renewable sources was greater in 1950 than today. In 1950, around 30 percent of electricity in the U.S. came from renewable sources; the figure today is about 20 percent. How could that be the case?

The answer revolves almost entirely around hydropower. In 1950, the entirety of the United States’ renewable energy production came from hydropower, while today it comprises only a fraction of American electricity generation — 6.3 percent, below wind’s share at 9.2 percent as of February 2022. While much of this production came from New Deal mass projects such as the Grand Coulee Dam in Washington state or the facilities of the Tennessee Valley Authority, a non-insignificant amount was derived from smaller private facilities, which also predated these larger facilities for the most part.

It is the latter that is relevant to Eastern Iowa’s part in this conversation. Dams along Iowa rivers, often by natural falls and rapids, first began to appear in Iowa in the 1830s for the purposes of grinding grain into flour and cutting logs into lumber, with well over a thousand in operation by the 1870s. From the late 1800s onward however, the displacement of wheat production in Iowa to corn, cattle, and pigs — a situation which remains more or less unchanged to this day — resulted in the closure of most of the old mill dams, with some converted to generate hydroelectric power instead. This was the case with the roller dam along the Iowa River in Coralville — originally a gristmill opened in 1844 and for a time operated by Iowa’s Civil War governor, Samuel Kirkwood, it was subsequently converted to hydroelectric operations from 1902 to 1968, from which the restaurant at the site today derives its namesake.

During much of the last century, Eastern Iowa was dotted with several other hydroelectric dams of similar scale and capacity. At various points in time from the 1920s to the early 2000s, the dam which created Lake Delhi, the roller dam along Burlington Street in Iowa City, the dams near B Avenue along the Cedar River in Cedar Rapids, and their eventual replacement, the 5-in-1 Dam, all generated clean, local hydroelectric power in some capacity. Nevertheless, hydroelectric dams never gained the prominence the mill dams once had, and most of these had closed down by the 1970s, with one report citing the simplicity of fossil fuels such as coal — plentiful, transportable by rail, and also found in Iowa — outpaced any appetite Iowans might have had for additional hydroelectric capacity.

There are other issues with dams as well. The creation of a reservoir from damming a river naturally submerges land which used to be above water; in the American South, this often involved the destruction of towns predominantly populated by Black people and subsequent forced relocations, leaving behind what is sometimes referred to as “drowned towns.” Indeed, the creation of Lake Red Rock through damming near Pella involved the submerging of several towns.

The efforts made in Iowa to dismantle old, particularly low-head dams are based upon real environmental and safety concerns. By impeding the natural flow of rivers, dams can block the passage of sediment and fish, disrupting natural cycles of life and accelerating soil erosion. Iowans using the state’s waterways for recreational purposes are also killed by becoming trapped beneath dams, in particular low-head dams whose circulating currents are notorious enough to garner the nickname “the drowning machine.” A map of dams in Iowa maintained by the Iowa Whitewater Coalition is littered with fatalities from encounters with dams going back to 1900.

In spite of these challenges, I have long been curious about the potential for these sites to generate hydroelectric power once again. The replacement of items which run on fossil fuels such as gasoline-powered cars and natural gas stoves with their electric counterparts, along with the clean generation of that electricity itself, has long been cited as key components in mitigating climate change.

In this respect Iowa is not doing too bad; as of May 2022 over 76 percent of Iowa’s net electricity generation is estimated to originate from renewable sources, mostly wind. However, only around 2.3 percent of Iowa’s net electricity generation originates from hydropower, still suggesting an untapped internal capacity for additional clean power in Iowa. A 2012 report from the Department of Energy found that Iowa had a potential hydroelectric capacity of 427 megawatts from nonpowered dams, enough to more than quadruple Iowa’s hydroelectric energy output. One of these potential dams, the aforementioned Red Rock Dam, was retrofitted with hydroelectric capabilities beginning in 2014 and began generating power this past spring, about 50 years after the dam was initially constructed. It is expected to last for close to a century.

Austin Wu is a Gazette editorial fellow.

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