Ask a Scientist – GHOST

We ask Marcela Politano, University of Iowa, the question: How does GHOST impact Iowans’ daily lives?

The Impacts of Pharmaceuticals in a Temperate Stream Dominated By Wastewater Effluent

Each year, the Iowa Water Center (IWC) offers two grant research competitions for the water community, with one being restricted to Iowa while the other is open to nationwide projects.

One of the national projects that we [IWC] have funded is centered around the ecological impacts of pharmaceuticals in effluent-dominated streams. The primary investigator of this project is Gregory LeFevre, with assistance from graduate student Hui Zhi.

This has been an ongoing project for multiple years, with the first year of earning the grant being 2017. You can read their initial abstract from 2017 here. This research project was also recently published in the journal Environmental Science and Technology, which you can read here.

Over two years, the team measured and monitored the spatiotemporal, or the dynamic of changes in space and time, of the levels of different pharmaceutical compounds in the wastewater treatment plant that is nearby North Liberty, Iowa. After gathering the necessary data, they then analyzed the information to figure out exactly what occurred when the pharmaceuticals entered the effluent-dominated stream.

“Most of the time, people think about effluent dominated streams being in a dry region,” explained LeFevre, “but they’re actually much more common than people would expect in temperate regions.”

North Liberty is considered a medium sized community, with relatively small streams, which is quite common to find in temperate regions of the United States. LeFevre explained that this can change the dynamic of the chemicals in the stream, which is what inspired the goal behind this project.

The main objective when this project was initially coming to life was to understand how chemical mixtures occur, but then also how they change throughout time and space along the stream. The idea is to understand specifically what these mixtures are, how they evolve, and then connect those patterns with biological effects.

After collecting water samples from the stream, the team sent these samples to the School of Freshwater Sciences at UW-Milwaukee, where a co-investigator of this project, Rebecca Klaper, is the Director of the Great Lakes Genomics Center. Klaper and her team, consisting of Dana Kolpin and Luke Iwanowicz, added these water samples to laboratory raised fish in order to test the effects that the water had, or didn’t have, on the fish at the genetic level.

In addition to this investigation portion of the project, Klaper and her team also raised native fish in a laboratory, then caged and added them to the same stream for four days. After the four days, the fish were then dissected and are currently undergoing genetic analysis.

“Chronic exposures can have long-term biological effects to fish,” said LeFevre. “What we’re interested in is how these potential mixtures might accidentally change through the aquatic environment for the fish, as well as how the mixtures themselves might change because of other variables.”

Even though they have gathered everything necessary for this particular study, the team is not finished yet. Along with assessing the data that they have collected; the team is planning on utilizing this stream site to its maximum potential for future projects relating to fish habitats non-target analysis.

Gregory LeFevre is an assistant professor in Civil and Environmental Engineering at the University of Iowa, as well as an assistant faculty research engineer at IIHR – Hydroscience & Engineering. If you would like to learn more about his work, you can visit his laboratory website here, and his Google Scholar page here.


By: Meghan Hanley, Outreach and Engagement Assistant

University of Iowa’s IIHR–Hydroscience and Engineering Expands Water Assessment Modeling

The word “ghost” has adapted a new meaning, in addition to the initial Halloween Casper-the-friendly-kind, for the water community. GHOST is a hydrologic model which allows users to be able to gather information, including land use, topography and geology, and be able to create predictions for streamflows. The name is an acronym, standing for Generic Hydrologic Overland-Subsurface Toolkit.

I had the opportunity to, virtually, meet and talk to Antonio Arenas Amado, to learn more about the creation, development and future of the GHOST program. Arenas is an associate research engineer at the University of Iowa’s IIHR–Hydroscience and Engineering and the Iowa Flood Center and a member of the team that created the GHOST program.

This program took quite a bit of time to finally come to life. The code development process and adaption of the model took around one year, with hours on end writing and verifying code and equations. Prior to the start of the development, the team had spent an abundance of time researching existing models, which helped them get a sense of an idea for what they wanted, or didn’t want, in their model.

This project originally started off by attempting to use a code already created by Penn State University, but it was later discovered that there would be several steps to adapt the existing model to what was needed for Iowa. The team created a new model, which is now the GHOST program, and continued to keep the same framework from the Penn State model.

Models are typically classified by the range of time that the model uses for data. The GHOST model is a long-term, continuous model, meaning that it can run and gather data for multiple years without stopping. Using this type of model allows the program to assess all of the activity within that time frame and identify patterns in drainage and flooding.

“If you imagine, when one drop [of water] falls from the sky, there are a bunch of potential paths for that drop of water to make it, or not make it, to a stream,” said Arenas, “so that’s what we try to account for in using this computational model.”

The inspiration for the creation of the GHOST model started off with a project for the Iowa Watershed Approach (IWA). The IWA, co-lead by IIHR–Hydroscience and Engineering at the University of Iowa, focuses on mitigating flood damage, which then led to the spark for the GHOST program.

There are a vast number of potential applications that the GHOST model can be used for. Arenas explained that a main use of this model in Iowa has been to help with the flooding issues that have occurred in the past years. So far, it has helped the state of Iowa discover new mitigation strategies for watersheds. Arenas also shared that where this program has helped in flood mitigation, it can also help in studying droughts as well.

“I think it is fair to say that we have more to do with the GHOST program than we have already done,” said Arenas.

Arenas shared a few examples of where he can envision GHOST being used or expanding in the future. First, he mentioned how much this program would be able to help with drought research and mitigation. Next, he mentioned that they were also hoping to add a water quality component to the model. Lastly, he explained the team has hopes of expanding the capacity of the computer speed of GHOST in order to be able to use it in larger watersheds and grow out of the small-medium watershed-level they are currently modelling.

The team that created the GHOST model consists of Antonio Arenas Amado, Dr. Marcela Politano and Dr. Larry Weber of the University of Iowa Flood Center and IIHR–Hydroscience and Engineering.


By: Meghan Hanley, Outreach and Engagement Assistant

Art and Conservation: The Interdisciplinary Vision of Felix Summers

Getting into Soil and Water 2020

Artists are not usually the first people who spring to mind when thinking about soil conservation in the United States. In the 1950s and 60s however, Felix Summers’ artwork introduced the Soil Conservation Service (now the Natural Resources Conservation Service) and big ideas about conservation farming to thousands of Americans. Even if they did not know his name, rural communities knew Felix Summers’ vivid, one-panel cartoons pointing out the dangers of soil erosion and the value of conservation farming.

In the mid-20th century, the Soil Conservation Service (SCS) used a team of technical illustrators in the Information Office to bring SCS ideas and publications to life. Professional artists illustrated complex scientific and engineering concepts not easily conveyed in text or photography. The tremendous number of informational bulletins, pamphlets, and other materials that flowed from the SCS in the mid-20th century often featured the work of these in-house illustrators. While most of their work illustrated specific manuals, guides, and public-facing pamphlets, the Information Division also provided a constantly expanding catalog of conservation cartoons to field offices. Field office staff across the country published the cartoons that best addressed local issues in local newspapers. These cartoons were many Americans’ first introduction to the SCS and conservation agriculture. Most of the over 400 cartoons in the artwork catalog were the work of one illustrator, Felix Summers.

Making His Way to the SCS

Felix Summers came to the SCS by way of two very different places: the New York City art scene of the 1930s and the Mills County Iowa SCS office. He began his art career at the University of Nebraska and went on to do post-graduate work at Yale, where he studied with muralist Eugene Savage. Summers’ style reflected the contemporary influence of the Regionalist school made famous by other Midwestern artists such as Thomas Hart Benton, John Steuart Curry and Grant Wood. Iowan farmers since before the Civil War, Summers’ family was steeped in agriculture. His rural upbringing outside of Strahan, Iowa informed his artistic focus on scenes of agrarian and rural life. Despite his rural roots, Summers spent five years painting murals in decidedly non- rural Manhattan department stores and nightclubs, including the storied Cotton Club and the El Morocco. World War II deferred Summers’ early artistic career as a muralist when the Army drafted him to serve with the combat engineers. After the war, the art world’s tastes moved away from Summers’ agrarian Regionalism – rejecting the familiar, rural scenes that were his specialty.

Showcasing His Skills

Looking for work after the war, Summers returned home to Iowa and took an entry-level job as a conservation aid at the Mills County office of the SCS. His skill at the drafting table lent itself well to conservation planning. Combining a growing belief in the mission of the SCS with his desire for artistic expression, Summers spent his evenings and weekends drawing cartoons designed to spread the gospel of soil conservation. His work drew the attention of SCS leadership, and he was soon promoted to the regional office in Milwaukee as a full-time illustrator. Beginning in 1948, the SCS began distributing Summers’ cartoons nationally. An agency reorganization moved Summers to Lincoln, Nebraska where he worked as an illustrator in the Midwest Regional Technical Service Center until his retirement in 1972. Upon his retirement, Summers received the USDA’s Superior Service Award for his illustrative work in service of conservation. Felix Summers died in 1987 at the age of 77.

Reaching a Wider Audience

The work of illustrators like Summers helped the SCS reach a wide audience not already familiar with the work of the SCS or the conservation movement. Cartoons provided a shorthand that quickly and succinctly conveyed why the work of the SCS mattered. Photographs provided examples, but art conveyed big ideas quickly and succinctly. Armed with something to say about conservation, the same artist who was out of style in post-war Manhattan nightclubs was right at home in midwestern newspapers. Summers’ cartoons drew in people who would ordinarily scan past what might have seemed like dry and technical articles about federal conservation efforts. Moreover, he conveyed SCS messages in a visual shorthand that spread the word to even the casual reader. When interviewed in 1952, Summers summed up his artistic approach: “to speak the language of farmers on their own terms, but do it pictorially. I wanted to interpret for other people all the sweat, strain, and worry that goes into farming.”

By summing up the importance of conservation agriculture in one panel cartoons, Summers provided an extremely efficient message that reassured those farmers and ranchers already practicing conservation and challenged those who were not. A New York muralist might seem an unlikely champion for conservation, but Summers widely distributed work remains a testament to the importance of a truly interdisciplinary approach to conservation.


Shelby Callaway

Historian, Natural Resource Conservation Service US Department of Agriculture


All images are from a copy of the mid-century SCS artwork catalog preserved in the Doug- las Helms Collection in the Special Collections Division of the USDA’s National Agricultural Library in Beltsville, Maryland.