Restoration Siting Protocol for Future Reef Construction
As of 2009, there are more than 100 completed oyster restoration projects in the Virginia portion of the Chesapeake Bay. Considerable interest in future construction warrants the development of a technique that allows the advanced identification of potential building sites based on existing data and best professional judgement.
The current protocol considers three basic criteria. These criteria were analyzed using a hierarchical approach that combines available digital data and GIS programming techniques. The resultant maps illustrate only the endpoints of these analyses along with ancillary supporting data.
First, the current protocol considers only public oyster ground in the context of these analyses. Therefore, the Baylor grounds (public oyster grounds) mapped by Lt. Baylor in the 1890s provide the state owned bottom on which oyster habitat would be constructed by federal, state or local programs. Second, oyster reef construction sites must be based on hard bottom, and preferably where oyster reefs once thrived. Geo-referenced bottom probe surveys conducted by Dexter Haven of VIMS in the 1970s present provide data verifying bottom sediment type
These data were used to identify areas within the public oyster grounds with hard bottom composed of shell or oyster rock. The third criteria used to designate suitable sites is based on the location of existing COE maintained navigation aids and channels. These data were included in the analyses to insure that reef construction would not interfere with either navigation or maintenance of those areas. While this represents a small percentage of the total number of channels and aids in Virginia waters, data were not available for other aids or channels not maintained by the COE. No targeted reef restoration sites were found to be in the vicinity of COE aids or channels.
Using the ArcMacro language (AML) developed by Environmental Systems Research Institute (ESRI) to accompany the ArcInfo software, the hierarchical model pulls from a GIS coverage representing the most recent survey of all public oyster grounds in Virginia. This coverage was digitized from the original mylar maps of the Haven surveys and is currently maintained at VIMS. This coverage was merged with data for bottom type, depths between 1 and 6 m, salinities in excess of 10 ppt, hard bottom substrate, and Baylor grounds. Analyses have been performed to determine optimal sites for future oyster reefs.