July 21, 2003 — As a primary natural feature of any bay’s shoreline, tidal wetlands have long been recognized for their importance in maintaining the environmental health and economic wealth of that region. Wetlands play a crucial role in the productivity of coastal waters, biogeochemical cycling and geomorphological stability; they act as nurseries for fish, shellfish and crustaceans and feeding grounds for birds; they store pollutants and nutrients; and they serve as buffer zones to flood events and wave action.

However, these fragile ecosystems have been degraded over the centuries due to both anthropogenic use and natural hazards. Due to their intrinsic natural value, restoring and sustaining healthy wetland ecosystems has become a national priority. Over the last two decades, creation and restoration of tidal wetlands has become a required form of mitigation. Dredging of shallow water areas is a major construction effort in which wetland creation has been used for mitigation purposes across the nation, including many areas in the Chesapeake Bay.

Fort McHenry Wetlands
The wetlands adjacent to the Fort McHenry National Historic Monument and Shrine were originally constructed in 1982 as mitigation for the construction of the Fort McHenry Interstate 95 tunnels in Maryland. They are now being reconstructed to serve as functioning wetlands through mitigation credits for a new, nearby port slip that will allow more containers to be offloaded.

Originally, there were three small culverts through the riprap encircling the wetlands, which allowed tidal exchange with adjacent harbor waters. Since then, the culverts have mostly silted in, largely cutting off tidal exchange and resulting in the degradation of natural salt marsh function at the site. Currently, modifications are being planned to promote regular, natural tidal flooding to the site, control debris accumulation, and enhance its habitat value to plant and animal species. These modifications will have direct benefits to the portion of the site that is either converted to new aquatic habitat or re-vegetated with native marsh vegetation. Benefits will also likely accrue to the entire site as a natural tidal flooding regime and hydroperiod is restored.

NOAA Helping to Restore the Fort McHenry Wetlands
The NOAA National Ocean Service Center for Operational Oceanographic Products and Services and National Geodetic Survey have signed a Memorandum of Agreement with the Maryland Port Administration to assist with restoration efforts at the Fort McHenry Wetlands in Baltimore. NOS is working with MPA and the National Aquarium in Baltimore on these restoration efforts. MPA is acquiring mitigation credits to restore the site into functioning wetlands and NAIB is providing technical oversight. NAIB also hopes that the demonstration at Fort McHenry will shape the requirements for other, future restoration efforts in the Chesapeake Bay to ensure that all are successful and sustainable.

Through this MOA, NGS has conducted Kinematic Global Positioning System surveys (i.e., aeronautical surveys requiring the collection of stereophotographic and remotely sensed data) of the site to obtain existing elevations and has completed a preliminary digital elevation model. CO-OPS has performed high water analyses and long-term sea level assessments on data from its long-term National Water Level Observation Network station at Fort McHenry/Baltimore, Md., which dates back to 1902. This combined information was provided in a NOS Report to Moffatt and Nichol — MPA’s contractor, which was used to design construction plans for the new wetlands site.

After construction occurs, CO-OPS will also install a tide station at the site for monitoring purposes and NGS will perform an additional geodetic survey. The local tidal datums will be computed relative to geodetic datums and critical marsh elevations to create an updated DEM. Because wetland vegetation is sensitive to how long and how often it is inundated, CO-OPS has also conducted frequency and duration of inundation analyses of the Baltimore NWLON station’s high waters. NAIB biologists will use this information to determine where and when to plant different marsh vegetation.

Coastal Zone '03 Conference
This year, the Maryland Coastal Zone Management Division and Delaware Coastal Programs hosted the for Coastal Zone '03 in Baltimore, Md., from July 13 to 17, 2003. This event is the premier international gathering of ocean and coastal management professionals from around the world and attracted more than 1,200 participants. A Coastal Zone '03 field trip to the Fort McHenry wetlands site provided a unique opportunity to highlight the merging of two, often distinct, fields: the marine transportation system and wetlands restoration. Field trip participants learned about the restoration and stewardship of one of the oldest created tidal wetlands in the upper Chesapeake Bay. Furthermore, they had an opportunity to speak with NAIB employees about the restoration efforts and visit the wetland monitoring station, which is maintained by local students and volunteers. NOS’ traditional Navigation Services, or MTS-support, offices (NOAA CO-OPS, Office of Coast Survey -OCS and NGS) all actively participated in this field trip by providing NAIB with water level, geodetic and bathymetric information to demonstrate the essential tools needed for successful restoration. Participants also saw the NWLON station at Baltimore, learned about KGPS, and boarded the NOAA (S/V) BAY HYDROGRAPHER to experience sample hydrographic surveying off of the Fort McHenry marsh site.

More information about each of these NOS offices follows:

• Center for Operational Oceanographic Products and Services: CO-OPS operates and maintains the National Water Level Program whose backbone is the National Water Level Observation Network. NWLON is a network of 175 long-term, continuously operating water level stations throughout the United States and its island possessions and territories. The tidal datums derived from these stations have traditionally been important for navigation and shoreline boundary purposes, however, there are other beneficial applications and services that water level and datum information can provide, including wetland restoration. In order to focus on these applications, such as wetland restoration, CO-OPS created its Coastal Oceanographic Applications and Services of Tides and Lakes Program.
  
• Office of Coast Survey: OCS is responsible for producing and maintaining the suite of 1,000 nautical charts that cover the coastal waters of the United States and its territories. It also provides hydrographic information for the safe navigation of maritime commerce, as well as basic data for engineering, scientific and other commercial and industrial activities. Navigable waterways are a critical component of Maryland’s economy — with 155 miles of coastal navigation channels at risk from coastal erosion.
  
  OCS’ Hydrographic Surveys Division operates the NOAA (S/V) BAY HYDROGRAPHER, which works mostly in the mid-Atlantic region and specializes in research and development of methods and equipment to acquire hydrographic survey data in support of the NOAA Nautical Charting Program. Typically staffed with one Officer-in-Charge and one-to-two Physical Scientist(s) or Survey Technician(s), this vessel is often used to demonstrate and test existing survey technologies, as well as attend many public events to demonstrate the latest hydrographic technologies to the public. LTJG Holly DeHart is the current Officer-in-Charge on this vessel and is the first female officer to head the development and navigation of this platform. Physical Scientist, Peter Holmberg, assists in acquiring and processing the hydrographic data collected by the BAY HYDROGRAPHER's side scan sonar and multibeam sonar units.
  
• National Geodetic Survey: NGS is responsible for providing the National Spatial Reference System throughout the United States. In order to accomplish this, it coordinates a network of more than 600 continuously operating reference stations, which includes a network of bench marks and Global Positioning System (GPS) base stations that provide access to the nation’s official horizontal and vertical positioning datums, such as the North American Vertical Datum of 1988 (NAVD88). In order for tidal datums such as Chart Datum (Mean Lower Low Water - MLLW) and water level analyses to be meaningful, they must be connected to geodetic datums (i.e., knowing what the water levels are without referencing them to land is not meaningful).

Through similar efforts, OCS and CO-OPS have been and are currently working on several similar type projects:

• NOAA’s Hydrographic Surveys Division BAY HYDROGRAPHER helped Maryland Department of Natural Resources scientists from NOS's Cooperative Oxford Laboratory characterize the bay bottom in two areas off the mouth of the Choptank River, along the eastern shore of the Chesapeake Bay. Using state-of-the art side scan and multibeam sonar equipment and on-board image processing capabilities, the vessel's crew developed mosaic images that provide a baseline for the Oxford scientists in their development of the Acoustic Seafloor Classification System.
• NOAA’s Survey Vessel BAY HYDROGRAPHER also assisted with the Oyster Planting Recovery Partnership in Maryland last year.
• CO-OPS is working with NGS and NAIB on similar wetland restoration projects at Barren Island Blackwater National Wildlife Refuge and Eastern Neck National Wildlife Refuge in Maryland.
• CO-OPS is also working with NGS on a similar wetland restoration project at Hamilton Air Force Base, San Francisco, Calif.
• CO-OPS has worked with NGS and ORR on the restoration efforts at Poplar Point, Anacostia River in Maryland.
• CO-OPS is working with ORR on the restoration of the LaBranche Wetlands in Louisiana.
• CO-OPS has also worked with ORR on the restoration of the Qwuloolt Marsh along the Ebey Slough in Marysville, Wash.

CO-OPS, also routinely supports OCS’ Hydrographic Surveys Division by providing tide reducers and tidal zoning for soundings taken during hydrographic surveys.

Relevant Web Sites
NOAA National Ocean Service

NOAA Center for Operational Oceanographic Products and Services

NOAA National Geodetic Survey

National Water Level Observation Network

NOAA NWLON stations in Maryland

NOAA Navigation Services

NOAA Office of Coast Survey

NOAA (S/V) BAY HYDROGRAPHER

NOAA OCS' Hydrographic Surveys Division

NOAA Nautical Charting Program

LTJG Holly DeHart

NOAA National Spatial Reference System

Media Contacts:
Glenda Tyson, NOAA Ocean Service, (301) 713-3066 ext. 191 or Ben Sherman, NOAA Ocean Service, (301) 713-3066 ext. 178