Wednesday, January 23, 2013

Good Ol' River Mud

"Tributaries Matter: Investigating the Biogeochemical Cycling of Reactive Constituents
in Sub-estuaries of the Chesapeake Bay"
I'll be honest. I wasn't sure exactly what I was in for with a lecture titled, "Tributaries Matter: Investigating Biogeochemical Cycling of Reactive Constituents in Sub-estuaries of the Chesapeake Bay." I was pretty confident I knew what a tributary was...and an estuary, but all that stuff in the middle? Not a clue. Yesterday we were fortunate to host Commander Joseph Smith from the US Naval Academy who was going to answer all my questions. We settled in to Litrenta, sat back, and learned some astonishing things about watersheds and sediment movement.

CDR Smith began his discussion with the Hudson River. All the way back to his time as a graduate student he has been studying the movement of sediment in estuaries. What he has learned has astonished his advisers and the wider scientific community. Instead of being like a pipe that dumps water into the oceans, estuaries experience constant movement of sediment toward the ocean and back toward the land. One example in particular encapsulated the importance of this multi-directional movement. In 2006 the Navy attempted to relocate the legendary World War II aircraft carrier USS Intrepid, but after a half hour of effort from a small fleet of tugboats, it became apparent that the ship was stuck in the mud! CDR Smith explained that this was a result of sediment being deposited in the harbor from upriver and from the ocean. The amount of sediment that settled around the ship worked out to be about 20 inches a year. This event, which confirmed CDR Smith's theory of high sedimentation rates, astonished the scientific community.

USS Intrepid with tugboats
Taking what he has learned about the tendency for estuaries to pick up materials, CDR Smith has focused his studies on nearby Blue Plains Advanced Waste water Treatment Plant to determine what sort of impact the waste water is having on the Chesapeake Bay. Specifically CDR Smith has been looking at a specific element Iodine 131. He was quick to point out that the levels at which he studied I131 were well below the levels that would cause any harm to surrounding populations. CDR Smith has been tracing I131 because it has comparable qualities (radioactive half-life) to other more harmful substances. This means that CDR Smith can more accurately model what would happen if one of the more harmful materials (heavy metals, pesticides, certain nutrients etc.) were to be released into the Bay's Watershed.

Among the many insights that Smith has gained through his work is the fact that environmental factors have a huge impact on the movement of these potentially harmful materials. Wind speed, wind direction, temperature, and pH are just a few of the factors that can influence the spread of these materials. In order to form a more complete model CDR Smith and CES Associate Director Doug Levin are working together to monitor every aspect of the Chester and the Severn. Among the many pieces of technology being used in this ambitious project are buoys that constantly collect data, and autonomous kayaks that will be able to independently patrol the rivers. This project, when completed, will make these two rivers the best known rivers in the Chesapeake Bay Watershed and potentially the entire United States.
Chesapeake Bay
Article written by Rachel Field, Program and Intern Coordinator for Washington College's Center for Environment & Society. 


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