Birds that require low, wet marshes diminish along with the food supply in ditched marshes. Building canals for flood control is another modification that increases surface water levels on marshes which, in turn, stresses and kills marsh grass. Any one discharge may involve only small amounts of chemicals which are diluted by the receiving streams, but when combined with other chemicals from multiple other discharges, significant concentrations of pollutants may result. The precise effects of these pollutants are still largely unknown, but the potential for problems is clear. Pollution may disrupt the food web in the salt marsh by killing off some species and prompting others to greatly increase in number.
Pollution also threatens the economic, aesthetic and recreational value of our marshes.
Permits regulate point-source pollution from a pipe or a single source industrial plant, but nonpoint source pollution is more difficult to monitor and control due to its multiple sources. Likely solutions include major changes in land use practices at the local level and adopting special methods to minimize runoff such as porous pavement, planting of buffer strips and construction of detention basins to contain road and agricultural runoff. Individual citizens can combat nonpoint source pollution by changing their everyday actions. There are a number of federal and state agencies and nonprofit groups that produce informational materials on regulations and conservation pertaining to salt marshes and other wetlands. It is important that citizens take a personal interest in conservation of marshes because of the benefits and values they provide for all of us now and for future generations.