Constructing a Watershed

Walking from my home across the walking bridge towards downtown Binghamton, we passed through a small park at the confluence of the Chenango and the Susquehanna rivers. I hadn’t seen this park before because I had always crossed the other bridge, but as we rounded the corner an historical marker caught my eye.


This took me aback, and I spent the rest of the evening researching the Chenango Canal and the Erie Canal. What caught my attention and grabbed hold of my imagination in reading this sign was the idea that, at one time, the Hudson River watershed, the Chesapeake Bay Watershed, and the Great Lakes Basin were all interconnected by a system of man-made canals. I don’t know how much water was actually flowing between these watersheds, but it seems probable that there was at least some mixing of the waters, and the result would have been a human-constructed super-watershed. This discovery blew my mind, and made me think again about the construction of a watershed as both a natural and a social reality.

A watershed is an interesting thing. Obviously it is a natural geographic boundary defined by elevation and geomorphology directing the flow of water. Natural processes like the flow of groundwater versus that of surface water, the movement of water from land to stream, the changes to the landscape caused by plants, animals, and weather all play a role in the quality and quantity of water within the watershed. But as we change the landscape and attempt to grapple with increasing water quality and availability issues, the watershed also becomes a social reality. Modeling, I would argue, plays a significant role in constructing the watershed – not only in a representational way (i.e. the way we think about the watershed) but also in a performative sense (the relationships that constitute the watershed as a socio-ecological system).

There is no particular reason why the Chesapeake Bay Model has to be a watershed scale model. The estuary had been modeled for years prior to the initial introduction of the watershed model, and other systems are managed using models that focus only on the water system itself. Modeling the watershed certainly adds data and makes for a more comprehensive model – it is, as many of my modeler friends would say, “the best science.” But there are tradeoffs. The watershed model is massive and complex. It has to simulate 64,000 square miles of land across a number of different geological zones. That’s no small task. The Bay Model does it well, but only after several iterations of the model, and they’re always working to improve the way that it represents different factors that affect water quality. Would it not be easier to simply take monitoring data of the inputs and run them through a complex estuary model? I’m not the one to answer or ask that question, but it seems to me that there are many options, and the watershed model is not a given for the Chesapeake Bay Program from a purely scientific or management perspective.

On the other hand, modeling the watershed has had a significant effect on the construction of social and political relationships surrounding the Chesapeake Bay’s water quality. The Bay Program itself is an excellent example. The Bay Program was founded in 1983 – the “Year of the Bay” as it has been called. At the time, the only partners in the Program were the states immediately bordering the Bay – Maryland, Virginia, Pennsylvania – as well as the District of Columbia and the Federal Government (represented by the EPA). The modeling of the Chesapeake Bay was underway, and the first version of the watershed model had been completed in 1982. In 1987, the next version (called Phase 1) of the model was released, and, for the first time, the watershed model was coupled to a simple estuary model. It was in this year that the next Bay Agreement was also signed – still only including those partners immediately bordering the Bay. This was also the first signed agreement in which the watershed was mentioned as a scale of intervention, particularly in reference to population growth, however most of the language still refers primarily to the estuary and its ecosystem.

Over the next decade and a half, the watershed model and the estuary model were improved, and an airshed model was also added to the suite. Then, in 2000, the signatories once again pledged to clean up the Bay with the Chesapeake 2000 agreement. For the first time, the watershed scale becomes the primary focus of the Bay Program. It’s also the first time that the headwater states – New York, Delaware, and West Virginia – are included in the plan. Now, with the 2010 TMDL “pollution diet” imposed by the EPA, the watershed scale is firmly cemented in the social structure of the Bay as all states within the watershed are responsible for some degree of nutrient reductions.

This connection between the development of the watershed model and the construction of the  Chesapeake Bay Program suggests that the modeling played a significant role in demonstrating the limitations of an estuary focused approach (i.e. including only the adjacent states in the agreement). These refinements, then, made possible – even inevitable – the construction of a watershed-scale management structure – the Chesapeake Bay Program itself. In the same way that a series of canals once linked three watersheds together, the watershed model has linked the Chesapeake watershed states together into a management super-structure that may (or may not?) be more capable of addressing the nutrient pollution issues that face the Chesapeake Bay.

As I explore more of the watershed now that I am living in its northern-most expanse, I encounter more and more these reminders that I am still in the watershed. Signs announcing my entry and exit from the watershed. Information posters at rest stops that talk about the watershed as an integrated system. It reminds me that the watershed is not simply a natural region. If we are to be effective at managing the problems facing the Bay and its tributaries, the watershed must also become a social reality. Modeling plays a significant role in that process of constructing social relationships and performing the Chesapeake as a watershed. Understanding how modeling affects that social reality, and the ways that the watershed can be imagined and performed differently is the subject of my ongoing research.

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