Recalling Grove Karl Gilbert at the 2019 AGU Fall Meeting

The Fall Meeting of the American Geophysical Society is a gargantuan affair that brings upwards of 25,000 earth and environmental scientists together for a week of presentations and conversations. The only way to make a meeting on this massive scale manageable is to divide it into smaller slices. In fact, one of the first decisions I faced when I arrived at the Moscone Center in San Francisco for the AGU’s 100th anniversary meeting in December was which of those slices I wanted to belong to. In the lobby of one of the conference buildings was a selection of lanyards for attaching nametags, colored according to broad categories of research in the earth sciences.

After a moment of deliberation (should I declare my allegiance to the social sciences?), I chose yellow, the designated color for geomorphology and hydrology. And throughout the meeting, I kept finding myself in rooms full of yellow lanyards, with only a speckling of blue, green, and other colors. In other rooms, scientists with those differently colored lanyards were probably having fascinating conversations about meteorology, climate science, the solar system, geophysics, and many other topics. But I didn’t hear those conversations. At the slice of the AGU that I was able to sample, the conversations were instead about sediment transport, landslides, river avulsion, landscape evolution, weathering, and so forth. For the moment, these were my people and my topics.

The sense of being part of a conference-within-a-conference was intensified on Saturday when I attended the so-called Gilbert Club at the Lawrence Hall of Science in the Berkeley hills. Not officially part of the AGU conference, the Gilbert Club — named for the pioneering US geomorphologist Grove Karl Gilbert — has been meeting annually in association with AGU since 1983, when a handful of quantitatively minded geomorphologists gathered at Berkeley geomorphologist Bill Dietrich’s home. Gilbert Club has since evolved into a field-shaping institution that convenes hundreds of geomorphologists each year to learn about the field’s latest research results and debate its future while reconnecting with old friends and colleagues. The day-long meeting begins with a round of introductions in which each of the hundreds of attendees states their name, affiliation, and any announcement they want to make, and it ends with an extended evening of pizza and beer.

This year’s Gilbert Club was punctuated by the presentation of a cake to Dietrich in thanks for his decades of service to the international community of geomorphologists. Tellingly, the cake was topped by a cutout of a mule being ridden by a Dietrich-shaped silhouette. In her speech presenting the cake to Dietrich, Dorothy Merritts — a geomorphologist at Franklin and Marshall College who is the outgoing president of AGU’s section on Earth and Planetary Surface Processes — told the audience that the cutout was a reference to Figure 15 of Gilbert’s influential 1877 Report on the Geology of the Henry Mountains. Captioned “Ways and Means,” the figure is an almost childish sketch of a mule’s head. For Gilbert, the sketch was a playful gesture toward the practical demands of field research in the late-nineteenth-century United States. For Merritts and the other geomorphologists honoring Dietrich, it was a reminder that Gilbert Club itself had become one of the important “ways and means” for twenty-first century geomorphologists to do their work.

Two things jump out in retrospect. First, appropriately for the AGU’s 100th anniversary meeting, today’s geomorphologists seem deeply interested in their field’s past even as they express uncertainty about the relevance of that past for shaping the field’s future. In the three-minute “pop-up” presentations that concluded the formal portion of this year’s Gilbert Club, a number of speakers challenged the audience to think harder about geomorphology’s lack of diversity and to take a more critical stance toward its social role, including its responsibility to indigenous communities in settler-colonial societies such as the United States and Canada. What relevance historical figures such as Gilbert still have for a science seeking to become more inclusive and more just remained an open question.

Second, the identity of geomorphology as a distinctive field of scientific research probably lies more in institutions such as Gilbert Club than it does in the development of any specific theory or method of research. This is not to says that theories and methods are irrelevant; it is clear that one of the things that binds Gilbert Club attendees together is their shared interest in using quantitative data to develop precise physical and mathematical models of geomorphological processes. (This is what makes them into an “epistemic community,” as some political scientists and STS scholars call it.) But what keeps people coming back each year — what keeps people thinking of themselves as geomorphologists — is not those epistemic commonalities alone. It is also the sense of being a member of a community bound together, if also sometimes divided by, certain experiences and values. Such experiences and values are as vital to the work of science as collecting data and developing models, and meetings such as the AGU and Gilbert Club are among the sites where they are created and contested.

A quiet moment in Cataract Canyon

The photo below, taken by William Emmett, is published on the website of the U.S. Geological Survey. Pictured are Ralph Alger Bagnold (left) and Luna Bergere Leopold (right, with guitar), seated during a quiet moment in an excitement-filled rafting expedition down the Green and Colorado rivers in March 1966.

Born in 1896, Bagnold is a generation older than Leopold (b. 1915), and already by this point a legend in his field, largely on the basis of his explorations of the Sahara in the 1920s and 1930s, his 1941 book The Physics of Blown Sand and Desert Dunes, and his establishment of the Long Range Desert Group during World War II.

Leopold, meanwhile, has just stepped down from a nearly decade-long position as head of the USGS’s Water Resources Division, where he was responsible for coordinating a veritable army of data collectors and research scientists and where he played a leading role in the development of the fields of hydrology and fluvial geomorphology in the United States.

By the time they were rafting down the Green River toward Cataract Canyon in 1966, Bagnold and Leopold had been collaborating for a number of years on studies of the processes that shape rivers and the landscapes around them. Even after their work together had largely run its course, they remained close friends, trading visits between Leopold’s cabin in Wyoming and Bagnold’s home in the United Kingdom. This photograph is, among other things, evidence of the kinds of field experiences that drew them together as scientists and as friends.

It is also evidence of the tangled roots of the science of rivers. From a present-day perspective, their close collaboration comes as something of a surprise. While both are recognized as seminal figures in fluvial geomorphology, they have come to stand for almost diametrically opposed research styles. To be a “Leopoldian” scientist is to search for correlations among the different parameters that characterize river systems (such as flow rate and channel shape), without worrying much about the basic mechanisms that produce those correlations. To be “Bagnoldian,” in contrast, is to focus precisely on those basic physical mechanisms, only turning to the behavior of actual rivers in order to validate (or invalidate) the physics-based models.

Defined this way, it is hard to be “Bagnoldian” and “Leopoldian” at the same time. But as this photo suggests, Bagnold and Leopold not only had much to learn from each other but also greatly enjoyed each other’s company. In some ways, they even needed each other to pursue their common science in the distinctive ways they did. Leopold needed Bagnold’s expertise in math and physics to refine his models of empirical relationships, for example, while Bagnold needed Leopold’s rich sets of data from real-world rivers to test his physics-based predictions. Both had resources and skills that the other needed—a kind of dependency that also characterized, and continues to characterize, the field of fluvial geomorphology as a whole.

Such surprising links between seemingly distant or even opposed approaches, which are often nurtured as much by personal relationships and embodied experiences as they are by shared techniques or theories, are a recurring theme in the history of river science—one that future posts in this series will return to.

Diving into the history of the water sciences

Over the next months and years, this website will be updated with the results of a National Science Foundation-funded research project at the University of Pennsylvania on the history of fluvial geomorphology—the scientific discipline that seeks to explain how running water shapes and reshapes the surface of the Earth.

The project focuses on the ways that new kinds of data—precise, quantitative, and abundant—were integrated into the work of geomorphologists from the 1950s through the 1980s, and on the profound transformations in both the practice of science and the management of rivers and streams that resulted.

More soon! In the meantime, check out a growing bibliography of key sources and more information about the project’s aims and methods and the team behind it, and don’t hesitate to contact us with any questions or comments.