J. Adam Riggsbee - Doctoral Dissertation Final Defense

Removal is rapidly becoming a viable management option for damaged, abandoned, or aged dams no longer serving their intended purposes. According the US Army Corps of Engineers and the Federal Emergency Management Agency (FEMA) there are approximately 76,000 dams (over 6 feet in height) in the United States which are capable of storing almost one full year’s runoff within their reservoirs. FEMA has also noted that more than 85% of these structures will be near the end of their operational lives by 2020. While an exact number is not available, it is estimated that nearly 500 dams have been removed from America’s waterways; most of which have been small, run-of-river dams. The burgeoning industry of ecological restoration is beginning to use dam removal as a restoration mechanism. The consequences of damming are well documented within the ecological and geomorphic literature, but few of the 500 estimated removals have incorporated rigorous scientific investigation. Damming alters stream hydraulics by slowing water velocities and increasing channel width and depth. Such hydraulic alteration results in most impoundments acting as retentive water bodies that, depending of watershed characteristics, are capable of storing significant quantities of sediments, organic matter and associated inorganic nutrients (N, P and C). Once dam removal is initiated it is anticipated that former impoundments will act as sources of sediment as well as organic and inorganic forms of C, N and P to downstream environments. Two small, run-of-river dam removals are investigated in North Carolina to determine some of the spatial and temporal heterogeneity of nutrient and sediment fluxes associated with dam removal.

Committee Members:
Dr. Martin Doyle (chair)
Dr. Stephen Whalen
Dr. Frederic Pfaender
Dr. Emily Stanley (U Wisconsin at Madison)
Dr. Emily Bernhardt (Duke)

For further information please contact Rebecca Riggsbee Lloyd by email at Rebecca_Lloyd@unc.edu