Argonne's study of wetland areas shows little evidence of environmental degradation by pipelines. The results indicated that ROWs installed under recent wetland regulations normally are revegetated within a few years after site closure with dense, diverse plant life similar to that in adjacent natural areas. These plant communities have propagated from naturally available species without special soil treatment or artificial seeding. Traditional maintenance by periodic mowing has been successful in allowing an herb stratum to develop. While ROWs encourage plant and habitat diversity for wetlands, there is no evidence that they degrade wetlands by encouraging the growth or spread of invasive, non-native plant species.
Most negative impacts are short-term, diminishing with time.
Older ROWs, developed before current regulations went into effect, had fewer positive results than those developed within the last several years. Natural gas pipeline companies recognize the Wetland Corridors Program as a unique data bank on wetland recovery. Future Plans One pipeline company has approached Argonne to survey some of its wetland crossings in similar fashion and compare the findings with the previously established data bank. Continuous studies are needed to document more precisely the duration of observed effects, the impacts of recent regulations limiting maintenance to only the central portion of ROWs, and further comparisons of directional drilling and open trenching. Studies are also needed to document potential fragmentation of various habitats and identify techniques to avoid this condition.