maximizing mitigation credits through monitoring methods.
Case studies in North Carolina, results and recommendations
for future projects.
Timothy W. Savidge, The Catena Group Inc., 410-b Millstone Drive, Hillsborough, NC 27278
Abstract:
Dam removals have become an increasing popular mitigation option in the Southeast. The interagency North Carolina Dam Removal Task Force (DRTF) was formed to prioritize dam removal and develop guidelines on how to demonstrate chemical and biological improvement and provided a mechanism for determining mitigation credits. The monitoring guidelines, which include various success criteria that determine the amount and type of mitigation credits potentially awarded, have evolved over the years as projects have been implemented. In North Carolina, monitoring of freshwater mussel populations following dam removal has been used as an indicator of the restoration of "appropriate aquatic community" criteria, and in many cases the "Rare, Endangered and Threatened (RTE) criteria as well. Several projects will be presented that highlight the various metrics incorporated into the specific monitoring protocols for each project, based on the applicable guidelines at time of implementation, to determine if the projects objectives were met. Additionally, subsequent studies in some watersheds suggest that ecological lift extended beyond the physically restored and credited reaches. In these cases, increasing the amount of mitigation credits awarded may be warranted. Using case studies, a methodology will be presented for developing realistic success criteria that capture ALL the ecological uplift from dam removal projects and maximizing mitigation credits.Dams are being removed around New England and the nation for a variety of reasons. The process of dam removal can be a long term benefit to fragmented mussel populations, provided a thorough understanding of sediment management has been developed. The management of sediment stored within the impoundment can be accomplished actively or passively, each having implications for mussels both within the impoundment and downstream of the dam. Active management focuses on removing or trapping sediment and limiting downstream transport whereas passive methods allow sediment to be exported from the impoundment as river headcuts progress upstream. This presentation will discuss mechanisms of downstream sediment transport and deposition, alternative sediment management strategies, and lessons learned. From a practitioner's standpoint, we will discuss the metrics used to identify appropriate sediment management strategies and minimize impact to aquatic organisms. We will draw on experience removing large and small dams in rural and urban environments to present lessons learned.
Biography:
Tim Savidge is the Environmental Supervisor of The Catena Group. Mr. Savidge has been
performing aquatic surveys, in particular freshwater mussels, throughout the Southeastern US since 1992. Mr. Savidge has lead over 600 surveys for freshwater mussels which have provided
information on species distribution for federally listed species. He has developed and implemented multiple aquatic faunal relocation and monitoring plans for various construction projects. He is currently serving as the Chair of the Scientific Council on Mollusks for the Non-game Advisory Committee to the NC Wildlife Resources Commission.
Timothy W. Savidge
Environmental Supervisor
The Catena Group
410-B Millstone Drive
Hillsborough,
NC 27278
919-732-1300
tsavidge@thecatenagroup.com