Dorothy Merritts

It's Relative: The Ups and Downs of Earth's Surface, Sea Level and Dams, and the Record of These Changes

A thunderous boom echoes through the air, shaking the ground underfoot and sending flocks of birds into flight. The stone wall of the once-proud dam stood no chance against the violent power of the explosives. Thousands of gallons of water rush out from behind the falling dam, turning a once tranquil stream into a gushing river. The water tears a path through the creek bed, leaving hundreds of tons of sediment in its wake. Though done with the best intentions in mind, the sudden removal of this dam will leave the landscape in devastation.

Professor Ron Harris of the BYU Department of Geological Sciences welcomed fellow colleague and scientist Dr. Dorothy Merritts to the March 3, 2025 seminar. Dr. Merritts is a geomorphologist who specializes in plate tectonics and soil formations in relatively recent geological events. She graduated from Indiana University of Pennsylvania in Geology before moving on to Stanford University, where she received her M.S. in Engineering Geology. She then went on to receive her Ph.D. in geosciences from the University of Arizona, where she focused much of her research on the northern edge of the San Andreas Fault. She is a recipient of many awards, including being elected to membership in the esteemed National Academy of Sciences in 2022. She currently works as a professor at Franklin and Marshall College.

Much of Dr. Merritts' work involves restoring wetland habitats to their original state. She is especially interested in preserving or restoring areas affected by the sudden and violent removal of dams, which is becoming more and more frequent as dams either collapse or are destroyed as they become obsolete. Often, when dams are removed without any proper preparation to the surrounding area, they leave a destructive path in their wake as years of collecting sediment is spit out into the riverbed, causing deep incisions and lateral bank erosion to occur and effectively laying waste to the environment. One example where such damage occurred was after the removal of the Condit Dam on the White Salmon River in Washington, one of the largest dam removals in U.S. history. Removing the dam, though ultimately beneficial, left unexpectedly profound damage that could have been avoided. Dr. Merritts proposes that instead of simply removing the dam instantaneously, work should be done to remove some of the sediment beforehand and then to remove the dam gradually instead of all at once. By doing these things, she hopes to raise awareness that will lead to the prevention of similar damage that harms the environment and wildlife.

Dr. Merritts also presented her work conducted at Little Conestoga Creek, Pennsylvania. By digging deep trenches that expose the layers of the ground, Dr. Merritts and her team discovered that years of river pollution and damming had led to a massive buildup of sediment in the area. They have been working diligently to remove the thousands of tons of sediment from the floodplain that surrounds the creek in an attempt to restore the environment to what it once was originally. By removing the sediment buildup, Dr. Merritts and her team hope to see improvements to the area, including the removal of harmful nutrients, and perhaps inspire similar restoration projects around the country.

Although there is a plethora of vital functions that the study of geology performs, Dr. Merritts' work showcases one of the most important aspects: Bettering the world around us. Through our understanding of how the world works geologically, we are able to preserve and restore the beauty that nature offers. We improve the lives of wildlife and plant life, and our society becomes safer, more responsible, and better overall.