130 • Wetlands: Their Use and Regulation 



Feasibility of Compensation 

 or Off site Mitigation 



Creation 



Producing a new wetland usually involves filling 

 an open-water or upland ecosystem, which may, 

 in itself, possess important values. Developing a 

 new wetland entails providing the proper substrate 

 level and type, assuring chemical compatibility, and 

 providing erosion control during establishment of 

 vegetation. The complexity of these factors intro- 

 duces considerable risk of failure; however, the 

 historical record shows that creation of wedands can 

 be successful, given proper site selection and 

 preplanning. 



Marsh creation has occurred mainly in coastal 

 waters or along shorelines that are not exposed to 

 large storm waves or the wakes of ships (20,39,60). 

 Planting aquatic plants predates the 1940's. 

 Marshes of various sizes have been developed along 

 the Mississippi River since the 1930's, in Utah in 

 the 1930's and 1940's, and in Wisconsin and other 

 States since the 1940's. Although some projects 

 range up to several hundred acres in size, marsh 

 creation by means of artificiad plantings tends to 

 be on a smaller scade (0.1 to 10 acres) owing to high 

 costs for establishment. 



The largest concentration of projects has occurred 

 in brackish and saline environments along the mid- 

 Adantic and Southeastern coasdines. Wedands also 

 have been created successfully in New England, 

 along the Gulf Coast, particularly in Texas (57), 

 and along the west coast [e.g., San Francisco Bay 

 and the Columbia River estuary (51)]. Some 

 freshwater marshes have been established on rivers 

 (55), on the Great Lakes (59), in isolated ponds as 

 part of surface-mine reclamation (1 1), and in sew- 

 age lagoons, to assist with wastewater treatment 

 (16). 



Restoration of Wetlands 



Restoration involves taking an existing marsh 

 from a poor, unhealthy, or degraded state to the 

 level of productivity and habitat value associated 

 with undisturbed natural wedands occurring in the 

 vicinity. This process often can be accomplished 

 by changing surrounding water inflow or drainage, 

 eliminating erosion and siltation, and reducing 



pollution from adjacent areas (6,29,46). Restored 

 areas generally will have at least some semblance 

 of the natural elevations and substrate unless ero- 

 sion or sediment deposition has been severe. Resi- 

 dual populations of natural plants usually are pres- 

 ent to serve as seedstock for widespread regenera- 

 tion. However, re-creation of wedands has occurred 

 from seed remaining in the soil for decades. 



Restoration, although not widely reported, has 

 been practiced in estuarine systems where diking 

 has degraded coastal wedands (33,47), in areas 

 where normal sediment input or hydrologic patterns 

 have been disrupted (48,49), and in brackish or 

 saline marshes that have been modified heavily by 

 construction activities or exposed to different types 

 of pollutants (55). In some cases, freshwater wet- 

 lands have been restored, as in the case of Florida's 

 extensive freshwater ecosystems (50,52). Marsh-res- 

 toration projects tend to be small — usually 20 acres 

 or less. 



Costs of Creation and Restoration 



Any successful marsh-creation or marsh-resto- 

 ration project must involve costs for project plan- 

 ning, site investigation, careful seasonal schedul- 

 ing, and postproject monitoring. Total project costs 

 typically range from $250/acre for a small, relatively 

 simple marsh-creation project (57) to over $6,000/ 

 acre for a marsh established for sewage treatment 

 (16). Transport of substrate material by barge, 

 truck, or dredge, and subsequent site preparations 

 usually account for the largest single cost wherever 

 the site requires extensively raised elevations. In 

 most newly created wedands, artificial plant propa- 

 gation is also a necessary and significant cost. 

 Scheduling of project operations within natural en- 

 vironmental constraints, such as the periods of 

 tides, plant germination time, and limits of the 

 growing season cam increase costs in the short term 

 but will contribute gready to project success over 

 the long term. In general, it is far less cosdy to 

 restore degraded wedands than to create new wet- 

 lands. 



Prospects for Success 



The success of efforts to create or restore wet- 

 lands depends on many factors, including wetland 

 type and location, project scope and size, materials 



