CRS-60 



alter wetland functions; declines in wetland function as a result of such 

 actions have been documented. 45 / 



Modification to adjacent lands also affects wetlands. Whether these 

 lands are modified for an extensive purpose, like agriculture, or a more 

 intensive but geographically limited use, such as residential or commercial 

 structures, the runoff from both types of areas typically reduces wetland 

 functions. Runoff may contain contaminants and sediments. For example, the 

 runoff from highway surfaces contains petroleum residues and various heavy 

 metals as well as road salts and other chemicals or contaminants that may 

 have been spilled or washed off passing vehicles. Indirect activities are 

 generally more difficult to control both because their impacts on wetlands 

 are often not anticipated, and because these activities have other economic 

 and social values that many believe should not be limited or altered due to 

 uncertain effects on wetlands. 



Creating Wetlands 



While the activities described above have reduced wetland acreage and 

 functions, the U.S. Army Corps of Engineers has initiated a program to create 

 new wetlands at six sites around the country in an effort to dispose of dredged 

 spoil in an environmentally positive manner. 46 / Alternative plant species 

 are being tried, and some wetland functions are being evaluated. Guidelines 



45 / Darnell, Rezneat M. Impact of Human Modification on the Dynamics 

 of Wetland Systems. In Greeson, Clark and Clark, Wetlands Functions and 

 Values, p. 200-209. Many articles on aspects of this topic have been pub- 

 lished in popular literature. A good example is: Gary A. Soucie. We Can 

 Still Save Salt Marshes of Georgia, Carolina. In Smithsonian Magazine, 

 v. 5, no. 12. Washington, Smithsonian Associates, March 1975. p. 82-89. 



46 / Environment Laboratory. Wetland Habitat Development with Dredged 

 Material: Engineering and Plant Propagation. Technical Report D5-78-16. 

 Vicksburg, U.S. Army Engineers Waterways Experiment Station, 1978. 107 p. 

 and Appendices . 



