Anthony Lamoreux, a civil and environmental engineering (CEE) master’s student and graduate research assistant at IIHR—Hydroscience and Engineering (IIHR), explores how streambank vegetation impacts river and stream flow, contributing to a measure labeled as “roughness”. His research focuses on the seasonality of roughness as vegetation grows rapidly in the streambanks during spring then decays in the fall and winter months. Height, density, and the leaf area all impact the speed of streamflow coming through a river’s banks. The research improves the accuracy of streamflow predictions by correcting for seasonal stream roughness variation, informing and improving overall flood forecasting.
Lamoreux’s research is a small portion of a larger project funded by the National Science Foundation. The research is being conducted under Marian Muste, IIHR research engineer, and Priscilla Williams, an assistant professor in CEE who leads the Williams Erosion and Sediment Transport (WEST) Laboratory.
“The main problem we’re trying to solve is that roughness is associated with numbers created in a lab – different plants have very general assigned values. This makes it difficult to achieve complete accuracy,” said Lamoreux. “Even though roughness values are a constant, vegetation through the seasons is not. That’s what we’re trying to get to the bottom of – we expect roughness to increase as plants grow in the spring.”
Ensuring these roughness values are accurate is incredibly important for assessing streamflow and flood risks. Vegetation, which informs the roughness value, will fluctuate over the course of the seasons leading to potential inaccuracies in streamflow prediction. This can create minor issues for one stream, but at a statewide scale, these inaccuracies compound and can become big problems in terms of calculations and predictions.
“We have flood forecasters and researchers looking at USGS gages, and we expect them to be right. Unfortunately, that’s not always the case, so we need to improve the overall accuracy. There’s a lot of people who count on this information, and we want to supply them with the best, most accurate information that we can,” said Lamoreux.
Growing up in La Mars, Iowa, he experienced severe flooding in 2011 that left a lasting mark on his region and life trajectory.
“I experienced not only the devastation of my community, but the ongoing response to the flood over the course of the summer,” said Lamoreux. “It became an important goal for me to understand what happens during a flood. I went from asking these big questions about the flood I experienced as a kid to answering them for people who have similar and bigger questions now.” His research has led him across the state to do fieldwork and data collection, providing valuable hands-on experience that he hopes will help him get a job in the public sector after graduating.
“I’ve always had a pull towards the public sector – when there's enough of a public push, issues like flooding can be brought forward to create positive changes in the way Iowans approach these challenges,” said Lamoreux. Referencing the 2008 floods that led to the creation of the Iowa Flood Center, Lamoreux is motivated by public-driven change that can result in more resilient communities and critical infrastructure.