Virginia Institute of Marine Science
Recent efforts have sought to expand the use of “Living Shorelines” by waterfront property owners in Virginia and Maryland to combat tidal shoreline erosion. Living shorelines represent a shoreline management option that combines various erosion control methodologies and/or structures while at the same time restoring or preserving natural shoreline vegetation communities. Some regulatory agencies and non-governmental organizations prefer living shorelines over “traditional” shore hardening using bulkheads or stone revetments because these structures create a “barrier” or disconnect between the upland and marine environments. Typically, creation of a living shoreline involves the placement of sand, planting marsh flora, and, if necessary, construction of a rock structure on the shoreline or in the nearshore (Figure 1). When any type of material, sand and/or rock, is placed below/beyond mean high water (MHW) two situations could occur: 1) encroachment onto regulated lands necessitates a permit and 2) one habitat is traded for another -- non-vegetated wetlands and/or nearshore bottom for marsh fringe and rocky substrate. Encroachment beyond mean low water (MLW) in Virginia (MHW in Maryland) is onto state-owned bottom. This latter point is of concern to the Virginia Marine Resources Commission (VMRC) which manages this region. Its concern is the determination of how much encroachment onto public state bottom is necessary for a shore protection project. The Virginia Chesapeake Bay Local Assistance Program (CBLA) regulates the area above MHW and the landward limit of tidal wetlands. They are concerned about how much encroachment landward is required for bank stabilization. The goal of this report is to offer some guidance toward these concerns, most particularly as it pertains to state bottom. Specifically, it is the intent of this report to look at encroachment primarily bayward of MHW/MLW for sill-type systems installed for shore protection.
Shore Protection, Coastal Management, Coastal Engineering
This project was funded, in part, by the Department of Environmental Quality's Coastal Resources Management Program through Grant #NA07NOS4190178, Task 94.01 of the National Oceanic and Atmospheric Administration, Office of Ocean and Coastal Resource Management, under the Coastal Zone Management Act of 1972, as amended.
Hardaway, C., Milligan, D. A., O'Brien, K., Wilcox, C. A., Shen, J., & Hobbs, C. H. (2009) Encroachment of Sills onto State-Owned Bottom: Design Guidelines for Chesapeake Bay. Virginia Institute of Marine Science, William & Mary. https://doi.org/10.21220/V5QT4P