Excavating the Chesapeake: Exploring the Intersecting Geological, Political, and Technical Layers that Constitute a Watershed

By Jeremy Trombley, University of Maryland, College Park §

My research looks at the entities and interactions that constitute the Chesapeake Bay watershed – specifically the role that computational models have played in the process. In this post – departing somewhat from my comfort zone talking about lines and knots and rhizomes – I want to engage a different kind of ontology, an archaeological ontology of layers – in order to see where it takes me. With that in mind, I will attempt to excavate the stratigraphic layers of the watershed to look at the entanglements that shape our relationship to land, water, and one another. The stratigraphy I’ll be excavating is not a temporal stratigraphy or one of depth – it’s a structural and infrastructural one – and the layers are not overlapping, but intersecting and inter-acting. I will examine the layers of earth, rock, water, nutrients, plants, animals, humans, technology, and institutions that have shaped and continue to shape the Chesapeake today. 


Layer I: Watershed

 This is the Chesapeake Bay watershed. It’s a 67,000 square mile stretch of land that feeds almost 51 billion gallons of water into the Chesapeake Bay – the largest estuary in North America – every day. I am sitting in the watershed right now at my house in Binghamton, New York. Just downhill from me is the Susquehanna River, which is not only the major contributor of fresh water to the Bay, but also forms its main stem. As a result, I think about the watershed a lot. I think about it when I drive to work in Cortland following the Chenango and Tioughnioga rivers. I think about it when I drive through the watershed to DC to visit friends. I think about it when I drink a glass of water or flush the toilet. That water is flowing to the Chesapeake Bay. I am part of the watershed.

The watershed is formed – most apparently – by a relationship between land and water. 480 million years ago, the Appalachian range was formed from the same tectonic processes that caused the breakup of the supercontinent Pangea. Over time, the mountains were worn down by water, ice, and wind, but then given new life in the Cenozoic era by a process of regional uplift. These mountains provide the elevation that drains the landscape into the Bay, but the Bay itself was formed by other forces (Wennersten 2000).

Approximately 35 million years ago, an extra-terrestrial intervention occurred that would shape the Bay we know today. At that time, a large meteor cascaded down from the sky, and collided with the Earth in what was then the Atlantic Ocean just off the coast. With the repeated advances and retreats of ice sheets and corresponding rise and fall of the ocean, the surrounding landscape was carved into what we recognize today as the Susquehanna valley – the base of which is the Chesapeake Bay itself. A complex network of rivers and streams formed as the land and water shaped one another, but the Bay itself was slow in emerging.

When humans arrived in the watershed approximately 10 to 15 thousand years ago, there was no Bay. Slowly, the rise and fall of the tides would fill in the basin, giving shape finally to the Chesapeake Bay approximately 3000 years ago. In the intervening time since the Bay first formed, people have been entangled with the land and water – both shaping and being shaped by it. The native peoples of the watershed – the Susquehannocks (from whom the Susquehanna River derives its name), the Piscataway, the Powhatans, and many others – settled close to the rivers and the Bay and depended upon the water for food, cleaning, and transportation. By clearing the land for farming, and taking advantage of the rich resources the Bay and its tributaries provided, they also had a hand in shaping the landscape (Wennersten 2000). However, the changes they made were never as dramatic as those wrought by the colonization of the region by Euro-Americans.

When European colonists arrived and displaced the native people through violence and disease, they also settled near the water. They also depended on the waters for food, cleaning, and transport. In fact, the Bay and its tributaries were the infrastructure for the early colonists, serving as both a sewage and a transport system (Wennersten 2000). Many entrepreneurial colonists saw the network of rivers in the watershed as a potential highway system enabling trade and transport between the coast and the inland reaches. There were limitations to this highway, though. The unpredictable flow of water meant the rivers were often too shallow or too flooded to be reliable. Another impediment was the fall line – a line of cliffs that runs through the watershed and marks the boundary between the piedmont plateau and the Atlantic Coastal Plain – so named because of the series of falls that can be seen on the rivers running across it, Great Falls outside of DC being the most well known. These falls blocked the movement of large boats upstream (Wennersten 2000; Mancall 1991).

trombley002Historical marker indicating the site where the Chenango Canal met the Susquehannar River in Binghamton, NY. This marker is just down the road from my house.

The solution – envisioned by many including George Washington (Achenbach 2005) – was a series of canals that would provide reliable and stable flow of water, a mechanism for moving large boats beyond the fall line, and also the extension of the network into other portions of the continent. Most of the canals were never completed, but one that was – the Chenango Canal – is memorialized not far from where I sit now, and connected the Susquehanna River to the Erie Canal about 100 miles north of me. This network of rivers and canals enabled flows not just of water, but also of other resources down the rivers to the port cities along the Bay, and then out along trade routes across the ocean. These same flows brought goods and people – including African slaves – into the watershed (Wennersten 2000; Mancall 1991). As a result, the watershed was extended and the material flows that constitute it have been complicated dramatically. Today railroads and highways have replaced the canals, but the flow of resources in and out of the watershed continues to shape its landscape.

Layer II: Bay Program

The watershed is, in its most basic sense, a material structure shaped by geo- hydro- bio- and socio- dynamics – the complex interaction of forces both within and outside of its boundaries. But for all its complexity, the watershed was always just that – a drainage basin. In the last few decades, another kind of structure has emerged that adds another layer to the watershed. This layer is the socio-politcal structure that has arisen out of a concern for the Bay’s ecological health.

Over the past five centuries since the watershed’s colonization, increasing population, and degradation of the land have all taken their toll on the Bay (Wennersten 2000; Ernst 2003; Cooper and Brush 1993; Kemp et al. 2005). Increased flow of resources in and out of the watershed that was enabled by the rivers, canals, trains, and now roads caused dramatic changes in the landscape. Initially, there were flows of beaver pelts, wood, and tobacco out of the watershed. These flows unleashed another kind of flow – the flow of nutrients from the soil into the water. The decimation of the beaver population caused their dams to go unrepaired – dams that held back the flow of water and sediment and created vibrant wetlands. The clear cutting of the vast forests that once covered the region allowed water to fall unrelentingly on the ground and wash away the soil underneath. Tobacco farming stripped nutrients from the soil, leaving fields dry and fallow and in need of external fertilization by manure or synthetic nitrogen and phosphorous. Combined with the increase of impervious surfaces like roads and the channelization of the rivers to reduce the risk of flooding, nutrients now liberated from the soil were allowed to flow relatively unimpeded to the Bay (Wennersten 2000).

The Sediment Plume from Tropical Storm Lee and Hurricane Lee flowing into the Chesapeake Bay from the watershed.

Nutrients sound good– we all know that living things need nutrients to survive, but this unimpeded flow of nitrogen and phosphorous has saturated the Bay and changed its ecological balance. These dissolved nutrients feed plankton and other micro-organisms in the water, making the water so murky that no light can penetrate. The plants die, which reduces the oxygen in the water, which causes fish and shellfish to die off as well. Additionally, when the plankton die, they settle to the bottom, suffocating the oyster reefs whose job it is to filter them out. The result is a dead Bay except for the – sometimes toxic – algae that thrive in these nutrient saturated conditions (Cooper and Brush 1993).

Concern about the life of the Bay emerged in the late 19th and early 20th century, but existing political boundaries prevented meaningful response. The states that cared were the states whose boundaries encompassed major parts of the Bay and whose economies depended on the resources extracted from it – Maryland and Virginia. But the watershed flows from four other states – Pennsylvania, New York, West Virginia and Delaware. Getting those states to take part in cleaning up the water that flows into the Bay was essential, but also politically challenging (Ernst 2003).

To make matters worse, the Bay wasn’t always imagined as a product of its watershed. The tides flow in and out affecting salinity all the way to the fall line, and so the tide was often thought to be the major factor affecting water quality in the estuary. That view was changed by several factors, but most dramatically by a tropical storm that struck in 1972 (Malone et al. 1993). Tropical Storm Agnes made landfall in New Jersey and made its way into the upper Susquehanna watershed then lingered there dumping several inches of water in a matter of days. The city of Wilkes-Barre was underwater, the Conowingo dam was on the verge of failing catastrophically, and the sediment from the storm is visible in the archaeological record. All of this water flowed down the watershed and into the Chesapeake Bay carrying loads of nutrients unlike anything the Bay had seen before and it took years for those nutrients to flush out (Chesapeake Research Consortium 1977). This event shifted attention for the Bay’s health from the tides to the watershed. Scientific studies were commissioned – the largest of which was initiated in 1976 – new research organizations were formed – the Chesapeake Bay Commission, the Chesapeake Research Consortium – and, finally, a new management organization – the Chesapeake Bay Program (or Bay Program, as I’ll sometimes refer to it) – was established (“1983 Chesapeake Bay Agreement” 1983).

trombley004The organizational structure of the Chesapeake Bay Program. The Federal Government and watershed states as well as other “partners” compose the various teams, workgroups, and committees.

The Bay Program is a collaborative management organization including the federal government, the states in the watershed, and the District of Columbia. There is no other organization quite like it in the United States. The Bay Program was made possible by the clean water acts of the 1960s and 1970s, and the creation of the Environmental Protection Agency in 1970, which enabled the federal government to intervene in managing waters that cross state boundaries (Ernst 2003). As a result, for the first time, a true watershed management organization could be constructed, and this layer of structure has shaped the Bay and the watershed since its formation in 1983. It didn’t happen right away, though, even once the federal government became involved. For the first two decades, not all of the watershed states were signed on to the program – watershed management needed to be composed. It wasn’t until 2014 that all of the states became signatories to a single watershed agreement – though the Chesapeake 2000 agreement included all of the states as “partners.” Today, the Bay Program – headed by the EPA – is in charge of implementing a for the Bay watershed in which all of the states are legally obligated to reduce nutrient loads. This management structure adds a new layer to the watershed, and reconfigures it in various ways. However, we can dig even further in our archaeology. What structure lies beneath the Bay Program and its integration of policy and management across the watershed? What layers can we excavate next?

 Layer III: The Bay Model


The structure of the current iteration (Phase 5.3.2) of the Chesapeake Bay Modeling System. At the time of writing, the beta version of the Phase 6 model has just been released and is being reviewed by the CBP’s partners.

This is the Chesapeake Bay Modeling System, which I’ll refer to as the Bay Model. It is actually several models – a model of the Bay itself, a model of the watershed, a model of the airshed, and a scenario builder model that is a simplified version of the whole (Band et al. 2005; Linker et al. 2002). The Bay Model has been the focus of my research for the last couple of years as I’ve worked with modelers at the Bay Program and others working on different projects throughout the watershed. It is an elaborate computer model that simulates all of the complex physical and biological dynamics that take place across the watershed. It tells researchers the amount of nutrients flowing into the Bay and what happens to them once they get there including the effects on micro- and macro-organisms. The Bay Model is also used to predict the effects of different management scenarios on the Bay, and these predictions are used to determine how management will be conducted (CBP 2010).

This is not the first model of the Bay. A physical model of the estuary that covered over 9 acres and cost over 20 million dollars was built by the US Army Corps of Engineers in the 1960s and 1970s. It’s an interesting story, but one I don’t have time to go into here. Suffice to say that the physical model never really saw much use because it was constructed at a time when computational power and the complexity of computer models was beginning to supersede that of the physical models (Keiner 2004). The first computational Bay Model was completed in 1983 – the same year that the Chesapeake Bay Program was created (Hartigan, John 1983). The model has improved significantly in terms of its complexity and resolution over the last 33 years, but the basic premise is still the same – it is a watershed-scale model and its purpose is to inform policy and practice across the watershed. It is housed with the Bay Program for a number of reasons, but primarily two. First, it is a large complex model that requires an enormous amount of computing power, which means large computers and the resources to use them. Second, it requires a vast amount of data to calibrate, validate, and run. The data has to be assembled from many different states, jurisdictions, non-profits, private entities, and others, which requires a collaborative, inter-state organization like the Bay Program (Linker et al. 2002). The model has needs, and The Bay Program, as a watershed organization, has the resources to feed it.

Importantly, though, the Bay Program also depends upon the model such that there is an almost symbiotic relationship between the two. In my interviews with modelers and others involved in managing nutrients across the watershed, everyone who I’ve asked has said that the Bay Program would likely not exist without the model. In order for the Bay Program to continue to maintain its relational structure – its position in the federal government, its ties to the states, its role in implementing the “nutrient diet” – it needs a watershed-scale image of the Bay. That image cannot come from data alone – the quantity of monitoring stations would be unwieldy and the data unreliable. A model is needed to compose the watershed image. As a result, the model, which is built by the Bay Program, is also a performative part of the Bay Program’s structure as a whole. The model is the stratigraphic layer that underlies and gives shape to the Bay Program itself.


The three layers I’ve described intersect one another in a variety of ways. They give form to one another, and, through a continual process of inter- and intra-action, they transform one another over time. There is, of course, a lot more going on in the watershed – a lot more that could be excavated – but here I’ve presented a model – a simplified representation that allows us to grasp key elements and processes. The relationship between the Bay Model and the Bay Program is, I think, a pivotal one. It demonstrates the interconnection between our social dynamics, geo- hydro- and bio-dynamics, and the techno-dynamics that produce the Bay Model. It suggests that scientific practices not only shape our understanding of the world, but also the social and organizational structures through which we relate to it. It also allows us to imagine ways we might use scientific and technical dynamics not only to inform people about environmental problems, but also as a direct intervention enabling different forms of collaboration and organization. What other kinds of models could we build? What kinds of layers could we construct? What kind of watershed might emerge?

Works Cited

“1983 Chesapeake Bay Agreement.” 1983. Chesapeake Bay Program. http://www.chesapeakebay.net/content/publications/cbp_12512.pdf.
Achenbach, Joel. 2005. The Grand Idea: George Washington’s Potomac and the Race to the West. New York: Simon & Schuster.
Band, L., K. Campbell, R. Kinerson, K. Reckhow, and C. Welty. 2005. “Review of the Chesapeake Bay Watershed Modeling Effort.” 05-004. Maryland: STAC.
CBP. 2010. Chesapeake Bay Total Maximum Daily Load for Nitrogen, Phosphorus and Sediment. Annapolis MD: Chespeake Bay Program.
Cooper, S. R, and G. S Brush. 1993. “A 2,500-Year History of Anoxia and Eutrophication in Chesapeake Bay.” Estuaries and Coasts 16 (3): 617–26.
Ernst, Howard R. 2003. Chesapeake Bay Blues: Science, Politics, and the Struggle to Save the Bay. 1St Edition edition. Lanham: Rowman & Littlefield Publishers.
Hartigan, John. 1983. “Chesapeake Bay Basin Model Final Report.”
Keiner, Christine. 2004. “Modeling Neptune’s Garden: The Chesapeake Bay Hydraulic Model, 1965-1984.” In The Machine in Neptune’s Garden: Historical Perspectives on Technology and the Marine Environment, edited by Helen M. Rozwadowski and David K. Van Keuren, 273–314. Watson Pub International.
Kemp, W. M., W. R. Boynton, J. E. Adolf, D. F. Boesch, W. C. Boicourt, G. Brush, J. C. Cornwell, et al. 2005. “Eutrophication of Chesapeake Bay: Historical Trends and Ecological Interactions.” Marine Ecology Progress Series 303: 1–29.
Linker, Lewis C., Gary W. Shenk, Ping Wang, Katherine J. Hopkins, and Sajan Pokharel. 2002. “A Short History Of Chesapeake Bay Modeling And The Next Generation Of Watershed And Estuarine Models..” Proceedings of the Water Environment Federation 2002 (2): 569–82.
Chesapeake Research Consortium. 1977. The Effects of Tropical Storm Agnes on the Chesapeake Bay Estuarine System. Baltimore, MD: Johns Hopkins University Press.
Malone, Thomas C., W. R. Boynton, Tom Horton, and Court Stevenson. 1993. “Nutrient Loadings to Surface Waters: Chesapeake Bay Case Study.” In Keeping Pace with Science and Engineering Case Studies in Environmental Regulation., edited by Myron F. Uman. Washington: National Academies Press.
Mancall, Peter C. 1991. Valley of Opportunity: Economic Culture along the Upper Susquehanna, 1700-1800. Ithaca: Cornell University Press.
Wennersten, John R. 2000. The Chesapeake: An Environmental Biography. Baltimore: The Maryland Historical Society.

Jeremy Trombley is a PhD Candidate in the Department of Anthropology at the University of Maryland, College Park. His research revolves around the role of computational modeling in the management of nutrient pollution in the Chesapeake Bay watershed. He currently teaches, writes, and makes his own simple models with NetLogo while living alongside the Susquehanna River in Binghamton, New York.

This post is part of our thematic series: The Nature of Infrastructure.