As such, previously less desirable properties, many fronted by huge expanses of marsh situated on shallow waterways were being developed. Access to the waterways was being accomplished by long piers over the marshes. As a result of high land costs, many parcels were relatively narrow and therefore close together. Construction of piers on each property as a result began to have a noticeable and significant impact on wetland resources. Within the last several years, the Maryland Department of the Environment has received numerous applications for long piers extending over significant expanses of tidal marsh.

These types of projects raise a number of environmental concerns about impacts to wetlands and the habitat they support. Aside from its own concerns, the Department has received input from the Maryland Department of Natural Resources (DNR), the U.S. Environmental Protection Agency (EPA), the National Marine Fisheries Service (NMFS), and the U.S. Fish & Wildlife Service (FWS), all identifying the many ways that these types of projects can negatively affect the health and vitality of Maryland's coastal wetland resources. For example, pier structures cuts off sunlight to a long swath of tidal marsh, killing the vegetation that lies beneath. This loss of vegetation represents a loss of wetland habitat and accelerates the erosion of the marsh that is naturally kept in place by the vegetation's root structure.

Bringing boat traffic in close proximity to the marsh further accelerates this erosion. Constructions of long piers also result in fragmentation of marsh ecosystem by erecting barriers to the movement of resident species throughout the marsh. For example, many wading birds need shallow waters and often prefer guts within marsh that offer protection from predators. However, densely spaced piers would hinder a birds escape route from a site and therefore would not be utilized. These same barriers, and the de-vegetated areas beneath piers, allow for the entry of non-native species to the marsh, further disrupting the natural balance of the coastal marsh ecosystem. Finally, the use of treated lumber in the construction of piers and pilings can introduce contaminants into the marsh environment as the chemicals used to treat the lumber leach out over time.

As a steward of Maryland's wetland resources, the Department has an obligation to consider fully these concerns and has carefully evaluated the biological and scientific research addressing these types of impacts. While the Department was undertaking its analysis, the research assistance branch of the National Oceanic and Atmospheric Administration - at the request of the State of Georgia - began its own analysis of these same impacts, culminating in a nationwide workshop of scientists, researchers, and managers to discuss existing research and policy relative to the construction of long piers over wetlands. Two workshops have been conducted and work on these issues will continue. The preliminary conclusions of the workgroup showed that, with the exception of concerns about the introduction of some non-native species, existing scientific research supports the concerns raised by commenting agencies.

Other East Coast States as well as some West Coast States are also seeing impacts associated with piers constructed over wide expanses of marsh. As might be expected, the different states take a variety of approaches ranging from denial of applications for piers extending over tidal marsh to minimizing the impacts associated with such piers. For example, Delaware limits the width of piers over marsh to three feet and the total length to 300 feet. The State of New York similarly restricts the length of piers over marsh.

It is Maryland's policy to preserve tidal wetlands and prevent their despoliation and destruction. MD. CODE ANN., ENV'T ART. § 16-102(b). In order to effectuate this policy while facilitating riparian property owners' access to navigable waters, the Department has focused its evaluation of piers over marshes to minimizing impacts to vegetated wetlands and open tidal water through alterations in the width and height of the proposed piers, and by encouraging shared, group, and community piers. Based on the research and coordination the Department has undertaken, limiting the width and height of the pier to three feet minimizes but does not totally eliminate shading impacts on underlying marsh vegetation while providing access to the waterway for riparian owners, including property owners with disabilities. Providing a maximum length on piers crossing wetlands would also provide beneficial in reducing impacts to marshes by fragmentation.

In conclusion, the State of Maryland is continuing its ongoing efforts with the NOAA Workgroup and is also pursuing additional research. These research efforts, while long term in nature, will provide the necessary scientific data to make sound policy decisions on the construction of piers over marshes.