Parallels with the Past

As IIHR begins its second century, some areas of research reverberate with echoes of the past, even while continuing to break new ground.

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Over the last century, the University Iowa has grown and changed. Through it all, IIHR— Hydroscience and Engineering has stood firm through floods, the Great Depression, war, and, most recently, a derecho and a pandemic.

IIHR’s landmark building, the C. Maxwell Stanley Hydraulics Laboratory, rises proudly alongside — and sometimes in — the Iowa River at the intersection of Riverside Drive and Burlington Street.

In its 102-year history, the building has grown by four stories and now houses many more researchers, staff, and students.

IIHR today includes the Iowa Flood Center and the Iowa Geological Survey. Research has ebbed and flowed over the last century, touching on rivers, wind, environmental changes, plumbing, and more. While some early areas of study are no longer active here, such as ice studies or firefighting nozzles, others have appeared to take their place, such as water-quality studies, subsurface processes, and artificial intelligence applications. Each of IIHR’s directors has taken the institute in a different direction, following emerging research needs and trends while adding his own passions and interests to the mix.

In this section, we chronicle a few of the major research enterprises at IIHR that have continued over the years.

Mississippi River Modeling

THEN Shortly after IIHR first opened its doors in 1920, researchers here helped to pioneer laboratory modeling as a way to answer basic questions about the movement of water. By the late 1920s, river models with a constant flow of water wound their way through large rooms at IIHR. To work on the models, students and researchers knelt on platforms above the water to make adjustments or take measurements. Their work, led by founding IIHR Director Floyd Nagler, helped demonstrate the value of reduced-scale modeling. It also contributed to the lock and dam system on the Mississippi River, which beginning in the 1930s made the river’s nine-foot navigational channel possible. It is still in use today. NOW Despite our ever-advancing technology, river modeling looks much the same as it did almost 100 years ago. Physical modeling is still an important part of IIHR’s research, but now computational modeling is also common.

Recently, IIHR researchers developed flood inundation maps for communities along the Mississippi River. Data collected at some Mississippi River pools were compiled and combined with numerical models and GIS to determine how floodwaters would behave in different communities in the area at varying flood stages.

These interactive maps are available on the Iowa Flood Center’s Iowa Flood Information System https://ifis.iowafloodcenter.org/ifis

TOP: Early river research at the Iowa Institute of Hydraulic Research included flumes and photography (1934).

TOP CENTER: IIHR’s 1934 erodible bed model of the upper Mississippi River at Alton, Ill. CENTER: IIHR and the Iowa Flood Center have recently developed online flood inundation maps for communities along the Mississippi River, available on the Iowa Flood Information System (IFIS) to help people be better informed and prepared for flooding.

bOTTOM CENTER: The Iowa Flood Center conducts bathymetric surveys of the river to develop its flood inundation maps.

bOTTOM: The Mississippi River at dusk.

Flood Research

THEN IIHR’s research into flooding began with the first director, Floyd Nagler.

In 1932, Nagler wrote a letter to the University of Iowa architect stating his concerns about potential flooding of the arts campus along the Iowa River. He warned that recent bridge construction had changed the landscape enough to make it impossible to predict how badly floodwaters could damage the proposed Art Building site.

In the same letter, Nagler also warned that, “A flood of this magnitude would be a great catastrophe, and would probably wreck almost every bridge crossing the streets, besides doing an untold amount of damage to the cities located on the river.” The 1930s-era Art Building housed the studio of Grant Wood when he taught at the university. The building flooded in 2008 and has remained closed ever since.

Nearly 60 years later, another IIHR director encouraged local city planners to reconsider a building project, this time a subdivision called Idyllwild on the north side of Iowa City. In 1990, then-IIHR Director John F. Kennedy explained in an interview with the Iowa City Press-Citizen that Idyllwild’s proposed location was approved based on flood maps from 1977, well after the maps should have been retired.

“My promise to you is that it will rain, and it will rain hard, and we will have floods.” Kennedy said.

Kennedy’s prediction also came to fruition, as Idyllwild flooded in 1993 and again in 2008. NOW Flood research at IIHR has advanced significantly since then. With a century of research and data behind it, the C. Maxwell Stanley Hydraulics Lab is now home to the Iowa Flood Center (IFC). The Iowa Legislature created the IFC in 2009 in response to the floods that had swept through Iowa the year before. IFC cofounders Larry Weber and Witold Krajewski recognized the need for more comprehensive flood mitigation efforts in Iowa.

Flood inundation maps, the Iowa Flood Information System, and stream-stage sensors are all part of the IFC catalogue of public services. Since its establishment, the center has offered easily accessible flood information to Iowans hoping to learn more about the state’s many waterways, and how current and future flood events may affect them.

TOP: Flooding in the 1920s sweeps through campus.

TOP CENTER: In 2008, floodwaters swallowed the University of Iowa Arts Campus, as predicted by founding IIHR Director Floyd Nagler.

TOP CENTER: Iowa Flood Center flood inundation maps provide instant access to detailed flood information for emergency managers, decision-makers, and homeowners.

bOTTOM: Floodwaters even threatened the C. Maxwell Stanley Hydraulics Lab in 2008. The lab, built on bedrock to withstand the onslaught, came through the disaster largely unscathed.

Ship Hydrodynamics

THEN Lou Landweber came to IIHR in 1954 from the U.S. Navy’s David Taylor Model Basin in Washington, D.C., where he served as head of the hydrodynamics division. When he arrived at IIHR, ship hydrodynamics as a field of research took off and continues full steam ahead today. His influence on IIHR was transformative. Landweber, who never considered himself an engineer, developed a strong theoretical and experimental research program in this area. Under his guidance, IIHR became a national leader in research related to naval architecture and ship hydrodynamics.

Always kind, calm, friendly, and unassuming, Landweber happily made time to help anyone who asked for his guidance, from coworkers to graduate students to fellow researchers.

Landweber’s compassion was surpassed only by his intellectual prowess. He could solve a complex problem while apparently gazing out the window. Landweber was also among the first to explore the potential of computational fluid dynamics. These early efforts in the 1960s would provide a foundation for later work at IIHR. Landweber would lay out the problem— usually classical equation-solving problems—and Matilde Macagno would program it. Together, they would solve the problem, using her computer expertise and his analytical knowledge. NOW Under the leadership of Professor of Mechanical Engineering and IIHR Research Engineer Fred Stern, numerical simulations play a key role in IIHR’s ship hydrodynamics research, which remains an area of strength for the institute.

Stern takes a three-pronged approach—experimental modeling in IIHR’s towing tank and wave basin; computational modeling (CFD); and uncertainty analysis.

Over his prolific career, Stern has won grants totaling more than $41M, mostly from the Office of Naval Research. This funding has helped support the development and instrumentation of IIHR’s towing tank and wave basin facilities.

IIHR is also branching out into other marine hydrodynamics applications. For example, Assistant Professor of Mechanical Engineering and IIHR researcher Casey Harwood studies the use of small amphibious vehicles and vessels in the violent, chaotic environment created by waves crashing on the beach.

TOP: The father of ship hydrodynamics at IIHR and friend to all, Lou Landweber.

TOP CENTER: Fred Stern has helped lead a CFD revolution in ship hydrodynamics at IIHR.

CENTER aND bOTTOM: Graduate student Andrew Arnold pilots the amphibious vehicle t the Coralville Reservoir while Casey Harwood observes.

Fish Passage

THEN In 1936, the Iowa Conservation Commission asked IIHR to research the efficacy of different types of fishways, or fish passageways. IIHR took on the project, building a variety of model ramps and ladders to help migrating fish make their way up and over a dam. By 1939, IIHR identified a model that seemed ideal for a wide variety of fish. Not only were fish making it over the dam, they seemed to vastly prefer it to older models.

The new type of fish passageway allowed fish to swim straight up and over the dam without worrying about “climbing” the ladder that was previously their only option. The older version required fish to jump to the next level of the ladder where they could pause before jumping again.

To test their designs, researchers placed large nets at the top of the dam and recorded the number and type of fish that climbed the new fish ladder every hour. They noticed that even fish who were only an inch smaller than the passage was wide were able to swim up the dam without issue.

The improved passageways were implemented along the Des Moines River and evaluated throughout the 1940s. NOW Forty years later, IIHR began working on a new fish passage project in the Pacific Northwest, diverting salmon around dams on the Columbia River. As adult salmon made their way up the river from the ocean, they encountered eight dams that hindered their progress.

Not only did the adult salmon find it difficult to move upriver, their offspring then faced tremendous danger moving downstream. An estimated 10% of juvenile salmon were lost at each dam without a diverted path, leaving their already dwindling numbers in peril. IIHR’s fish passageways allow salmon to circumvent the dam, keeping them out of the dangerous turbines.

TOP, TOP CENTER, aND CENTER: IIHR fish ladder studies for the Iowa Conservation Commission in the 1930s studied methods to help migrating fish bypass abandoned lowhead dams on Iowa rivers and streams.

bOTTOM CENTER: IIHR’s modern fish passage research included model studies of the Priest Rapids hydroelectric dam on the Columbia River in the Pacific Northwest, with the goal of improving the design of fish passage structures.

bOTTOM: IIHR Director of Engineering Services Troy Lyons visits a hydroelectric dam in the Pacific Northwest.

Dropshafts and Combined Sewer Overflows

THEN In the early 1980s, IIHR was asked to propose a solution to the problems faced by the Milwaukee Metropolitan Sewerage District (MMSD). Milwaukee had outgrown its storm-sewer systems, which carried a mix of stormwater runoff and sewer water. Large rainstorms caused Milwaukee’s sewers to overflow and spew foul-smelling, polluted water into basements, streets, rivers, and lakes.

The IIHR team developed a new twist in dropshaft design: a simple descending tangential ramp that was easier to construct and smaller than other vortex-flow inlets.

It was a design triumph that was relatively inexpensive, yet worked as intended. It functioned so well that other large cities soon adopted it. IIHR had, with a single dropshaft project, become an expert on underground combined sewer overflow storage structures.

TOP: IIHR researcher Subhash Jain (on ladder) studies a dropshaft model.

TOP CENTER: IIHR’s dropshaft design improved combined sanitary and storm sewers in cities around the world.

CENTER: Then-IIHR Director John Fisher Kennedy (center) had confidence that his team could improve dropshaft designs for sewer systems, and he was right! NOW IIHR continues to simulate (both physically and numerically) large sewer and stormwater conveyance systems for cities worldwide. Computational modeling is useful for this type of project, solving complex flow problems and providing solutions that can save time and money.

For example, IIHR was hired to review the design for several Metropolitan St. Louis Sewer District intakes or dropshafts, and later to construct physical models of the dropshafts.

IIHR constructed a 1:16 scale model of the large Forest Park Intake Facility. Researchers used the model to optimize the design and confirm that the vortex dropshaft intake would perform as expected.

IIHR was selected for the project based on staff expertise that emerged decades earlier under the leadership of Director Kennedy.

bOTTOM CENTER: IIHR’s Troy Lyons with a dropshaft model for a municipal sewer system.

bOTTOM: IIHR continues to be a global leader in modeling and research for wastewater and stormwater conveyance systems.